March 2009

Evidence-based Synthesis Program Department of Veterans Affairs

Health Services Research & Development Service

Prepared for: 

Department of Veterans Affairs

Veterans Health Administration

Health Services Research 

& Development Service

Washington, DC 20420 

Prepared by:

Greater Los Angeles Veterans Affairs Healthcare 

System/Southern California/RAND 

Evidence-based Practice Center 

Los Angeles, CA

Determining Key Features of 

Effective Depression Interventions

Investigators

Lisa V. Rubenstein, MD, MSPH

Professor of Medicine, VA Greater Los Angeles and UCLA

PI, HSR&D Center of Excellence for the Study of Healthcare Provider 

Senior Scientist, RAND Corporation

Los Angeles and Santa Monica, CA

John W. Williams Jr., MD, MHS

Professor of Medicine and Psychiatry, Durham VA Medical Center and 

Duke University

Director, Duke Evidence-Based Practice Center 

Durham, NC

Marjorie Danz, MD

Associate Scientist

RAND Corporation and VA Greater Los Angeles

HSR&D Center of Excellence for the Study of Healthcare Provider 

Behavior

Paul Shekelle, MD, PhD

Professor of Medicine, VA Greater Los Angeles and UCLA

Director, Evidence-Based Practice Center RAND Corporation

Los Angeles and Santa Monica, CA

Statistician

Marika Suttorp, MS

RAND Corporation, Santa Monica, CA

Research Assistant

Breanne Johnsen, BA

RAND Corporation, Santa Monica, CA
ii

This report is based on research conducted by the Greater Los Angeles Veterans Affairs 

Healthcare System and Southern California Evidence-based Practice Center (EPC) under 

contract to the Department of Veterans Affairs. The findings and conclusions in this 

document are those of the author(s) who are responsible for its contents; the findings and 

conclusions do not necessarily represent the views of the Department of Veterans Affairs. 

Therefore, no statement in this article should be construed as an official position of the 

Department of Veterans Affairs.

This report is intended as a reference and not as a substitute for clinical judgment. 

This report may be used, in whole or in part, as the basis for development of clinical 

practice guidelines and other quality enhancement tools, or as a basis for reimbursement 

and coverage policies. The Department of Veterans Affairs endorsement of such 

derivative products may not be stated or implied.
iii

table of Contents

Executive Summary......................................................................................................................1

Background.....................................................................................................................................1

Methods ..........................................................................................................................................2

Results.............................................................................................................................................3

Conclusions.....................................................................................................................................4

Evidence Report...........................................................................................................................5

Introduction.....................................................................................................................................6

Background ....................................................................................................................................7

Methods ........................................................................................................................................11

Methodological Overview ...........................................................................................................12

Search Strategy ............................................................................................................................12

Study Selection .............................................................................................................................13

Data Abstraction ..........................................................................................................................13

Example Table for how impact ratings were carried out ..............................................................16

Study Quality assessment ............................................................................................................17

Data Synthesis and Analysis.........................................................................................................17

Qualitative Analysis......................................................................................................................18

Peer Review .................................................................................................................................19

Results ........................................................................................................................................20

Literature Flow ............................................................................................................................20

Studies Included in Effect Size or Relative Risk Analyses...........................................................20

Correlations between Features......................................................................................................20

Overall Effectiveness....................................................................................................................21

Study Evaluation Design Features vs. Effectiveness....................................................................21

Associations between Intervention Featuresand Outcome Effect Sizes.......................................22

Impact Measure.............................................................................................................................22

Qualitative Analysis of Intervention Features Versus Outcome Impacts......................................22

Qualitative Analysis of Evaluation Design Features, Including Patient Comorbidity, Versus 

Outcome Impacts..........................................................................................................................24

Limitations....................................................................................................................................24

Conclusions...................................................................................................................................26

Tables and Figures ....................................................................................................................27

Appendix A...................................................................................................................................55

Appendix B...................................................................................................................................58

References..................................................................................................................................62
6

Introduction

Practice improvement to assure appropriate depression care is urgently needed. According to 

projections from the World Health Organi¬zation, depression will be the second leading cause of 

disability in the developed world by 2020 (Ormel J 1994; Murray and Lopez 1997). Primary care 

clinicians (PCCs) care for approximately two thirds of depressed individuals. Rates of optimal 

quality of care for depression, however, are low (Simon and VonKorff 1995; Hepner, Rowe et al. 

2007). 

Collaborative care models show promise as guides for achieving appropriate depression care 

in ordinary primary care practices. These models are organizational interventions that target 

the structure of primary care practice through changes in elements such as those identified in 

the Chronic Illness Care Model (Wagner, Austin et al. 2001). A previous rigorously conducted 

meta-analysis of thirty-seven randomized trials (Gilbody, Bower et al. 2006; Gilbody, Bower 

et al. 2006) showed the effectiveness of multifaceted interventions based on the collaborative 

care model (Katon 1995) for improving depression care and outcomes for primary care patients. 

These studies followed several other literature syntheses on improving care for depression in 

primary care that drew similar conclusions on the effectiveness of multi-component models 

(Gilbody, Whitty et al. 2003; Craven and Bland 2006). The success of multi-faceted collaborative 

care interventions contrasted with prior and subsequent targeted guideline implementation 

strategies such as screening alone(Goldberg, Steele et al. 1980; Rubenstein, Calkins et al. 1989) , 

screening plus reminders or management suggestions (Rubenstein, McCoy et al. 1995; Rollman, 

Hanusa et al. 2002) or education alone(Thompson, Kinmonth et al. 2000). 

Not only did collaborative care prove to be effective, it also proved to be cost-effective. A metaanalysis of 11 cost-effectiveness studies on collaborative care showed that the multi-component 

collaborative care models are within usually accepted ranges of cost-effectiveness, while 

educational interventions alone are not cost-effective (Gilbody, Bower et al. 2006). 

It is important in considering the impact of collaborative care interventions in primary care 

to recognize that depression of lesser symptom severity or complexity has severe impacts 

over time if not corrected (Hays, 1995). The effects of depression on job loss (Zhang, Rost et 

al. 1999; Schoenbaum, Unutzer et al. 2002; Schoenbaum, Sherbourne et al. 2005; Lo Sasso, 

Rost et al. 2006), social and family relationships, financial decision-making, and other aspects 

of functioning mean that early in its course, depression can initiate a potentially preventable 

downward spiral. Thus, effective treatment of the less dramatic presentations of major depression 

is critical to disability prevention. Yet low complexity patients are less likely to receive 

appropriate attention under usual care circumstances. Patients with severe depression symptoms 

and/or psychiatric comorbidities are more likely to be recognized in primary care settings than 

those with fewer symptoms (Borowsky 2000; Pfaff 2005; Barkow 2004). These complex patients 

are more likely to be referred to mental health specialists and to comply with the referral as part 

of usual care (Bartels 2004; Borowsky 2000). 

The wealth of evidence on the effectiveness and cost-effectiveness of collaborative care, however, 

is not matched by a clear understanding of what collaborative care features practices must 
7

implement to achieve results similar to the studies. Collaborative care intervention descriptions 

vary both in terms of what was done and in how intervention features are described. Two metaanalyses of specific intervention features relevant to collaborative care had negative results—i.e., 

the identified feature was not associated with greater effect sizes. These studies did not directly 

address collaborative care, but focused on organizational interventions for depression care 

improvement in primary care. The first was a Cochrane review of the effect of collocation of mental 

health specialists in primary care (Bower and Sibbald 2000; Mitchell, Del Mar et al. 2002). The 

second was a study of integration of mental health or substance abuse treatment in primary care 

(Butler 2008). Thus, to date, there have been no quantitative analyses of features of collaborative 

care that have been able to clearly identify intervention features associated with effectiveness. 

The purpose of this study is to support enhanced implementation of effective collaborative 

care for depression by identifying key intervention features that are consistently associated 

with greater impacts on outcomes across the many studies of this model. This will enable the 

development of practice guidelines, or best practices, that incorporate the best current evidence 

on the specific organizational features necessary for providing effective care to depressed 

primary care patients. It will also foster the development of measures of model adherence for use 

in determining the extent to which collaborative care as implemented matches the key features 

identified from the literature.

Background 

Conceptual Approach: Our basic conceptual approach to depression collaborative care was 

shaped by the chronic illness care model (Fig 1) first described by Wagner et al (Wagner, Austin 

et al. 2001). We viewed the collaborative care model for depression as a specific case of the 

chronic illness care model, and identified variables describing study interventions accordingly. 

Fig. 1: Chronic Illness Care Model

health system

Organization of Health Care

self- management

support decision 

support

delivery 

system 

design

Clinical 

information 

systems

Community 

resources and 

policies

Informed, 

activated 

patient

Prepared, 

proactive 

practice 

team

Productive

Interactions

Functional and Clinical Outcomes
8

Depression Collaborative Depression Collaborative 

Care 

Primary Care 

Clinician

Mental Health 

Specialist

Care

Manager Patients

80%

20%

 In general, collaborative care models aim to support primary care to prevent commonly 

identified deficits in how depression care is provided using organizational changes, tools, and 

materials (MacArthur 2003, RAND 2000, IMPACT Implementation Center 2008, Hepner, Rowe 

et al. 2007). Care deficits addressed by collaborative care occur in fulfilling the set of functions

necessary for achieving appropriate depression treatment. These functions are:

1) detecting depressed patients; 2) assessing patients with depression symptoms for depression 

diagnosis, symptom severity, history, and comorbidities; 3) triaging sicker patients to be seen 

by or followed by mental health specialists; 4) initiating treatment that accounts for patient 

preferences and characteristics; 5) promoting treatment adherence through early, active followThe Chronic Illness Care model postulates types of organizational changes that can support 

guideline-concordant clinical care. In the case of depression, several specific aspects of depression 

care highlighted in clinical practice guidelines (Agency for Health Care Policy and Research 1993) 

are targeted by studies using a Chronic Illness Care type collaborative care approach. These include 

depression detection (i.e., screening or case finding), assessment (i.e., diagnosis of depression, 

comorbidities, and contributing factors), proactive follow-up (i.e., contacting patients to support 

self-management), and mental health specialty input or care for complex patients. 

Collaborative Care for Depression: The early studies showing that improved depression 

outcomes can be achieved by multi-component organizational interventions that support primary 

care for depression were developed empirically, rather than theoretically. Intervention developers 

refered to these interventions as depression collaborative care based on their emphasis on 

linking clinicians and patients in a joint management effort(Katon, Von Korff et al. 1995; Von 

Korff, Gruman et al. 1997) (Fig. 2). Later developers also emphasized collaboration in terms 

of the enhancement of links between mental health, primary care, and patients through care 

management. However, as implemented across a variety of similarly constructed interventions, 

the term collaborative care has come to incorporate additional features and functions.

Fig. 2: Depression Collaborative Care 
9

up; 6) adjusting treatment based on patient depression symptom response; and 7) re-assessing 

patient symptoms after treatment to determine need for treatment continuation. All of these 

activities can be thought of as promoting 8) patient self-management support. These functions 

are difficult to deliver as part of routine primary care. Common barriers are that most patients 

do not wish to and/or are not able to access mental health specialists; resources for intensive 

individual mental health specialist care for mildly depressed patients are not available; patient 

and provider resources for attending primary care as frequently as needed during early treatment 

are not available; and time and training for primary care clinicians to perform needed symptom 

and history assessments are not available. Collaborative care models identify organizational 

resources, as indicated in the chronic illness care model, to overcome these barriers. 

Consistent with the chronic illness care model, a major emphasis of collaborative care interventions 

is delivery system design. Typically, these models identify personnel, such as nurses or pharmacists, 

to fill gaps in usual care for the depression care functions that are most difficult for primary care 

clinicians to fulfill. These personnel follow designated procedures, usually with identified decision 

support, including provider education. In some cases, clinical information systems are engaged to 

facilitate key functions. Patient self-management support is considered important for all patients with 

chronic illnesses. Depressed patients, however, by virtue of their depressive illness, feel hopeless, 

helpless, and apathetic—characteristics that promote the low treatment adherence seen in many 

studies (Katon, von Korff et al. 1992; Lin, Katon et al. 2000). Collaborative care interventions provide 

patient self management support by promoting pro-active follow-up (i.e., follow-up that is initiated 

by the provider, rather than the patient); by educating patients; and/or by activating patients through 

behaviorally-oriented interventions such as problem-solving therapy or cognitive behavioral therapy. 

Multifaceted organizational interventions carried out in routine care settings are challenging to 

synthesize through literature review. These interventions include features adapted to individual 

organizational settings and resources, preventing uniformity of types of interventions across 

settings. Echoing findings on collaborative care for depression, we found that multi-faceted 

organizational interventions targeting Chronic Illness Care Model primary care organizational 

features such as staffing and delivery system design were more likely to be effective in 

improving prevention quality than were other types of interventions (Stone, Morton et al. 2002). 

However, also similarly to prior reviews, we were unable to achieve a high level of specificity 

about the characteristics of these organizational interventions. Thus, while a strong signal can be 

detected across broad types of multifaceted interventions, it has been challenging to translate the 

broad signal into specific guidance for spreading these interventions. 

The first set of literature syntheses looked for a signal identifying a general type of depression care 

improvement intervention with positive effects. These studies identified multi-faceted collaborative 

care or chronic illness care type interventions as the only general type of intervention to date that 

had robustly impacted depression outcomes for populations of patients identified as depressed 

in primary care (Craven and Bland 2002; Gilbody, Whitty et al. 2003). Following this signal, the 

2006 Gilbody meta-analysis selected studies based on designation of one or more staff members to 

support management of depressed patients (care management), and showed overall effectiveness of 

the 37 selected randomized trials (Gilbody, Bower et al. 2006). A cost effectiveness meta-analysis 

of a similar set of interventions studies (Gilbody, Bower et al. 2006) showed that these models are 
10

relatively inexpensive, may save costs in the long run, and are more cost-effective in terms of benefits 

to patients than many other commonly-used clinical interventions. All of these literature analyses 

found that studies varied substantially in the exact configurations of intervention components and 

features used, as well as in what and how they report on intervention features and outcomes. 

In addition to variations in intervention design, studies vary in terms of the patient populations 

they enroll and in other aspects of their evaluations. For example, some studies include patients 

screened in as depressed from a primary care population, and referred to collaborative care. 

Other studies identify patients by asking primary care clinicians or by searching pharmacy data 

bases for patients recently started on antidepressants. The range of depression symptoms required 

for inclusion varies from subsyndromal to very severe. Some studies exclude patients with 

psychiatric comorbidities, while others include them. Most studies exclude the most complex 

patients. Some studies involve multiple practices, while others focus on only one or two. Some 

studies involve large practices, often within managed care organizations, while others address 

small network or private practices. Few studies report in detail on the dynamics of mental health 

specialty referral or communication (Butler 2008). Overall, little is known about how the variety 

of possible features affect the chances of impacting patient outcomes. 

In this study, we aimed to build on previous reviews using both quantitative and qualitative 

techniques, combined with extensive queries to authors to obtain unpublished intervention details. 

We aimed to identify articles that represented organizational change approaches to improving 

depression care for patients in primary care as emphasized in the chronic illness care model. Based 

on these, we aimed to describe the set of features that characterize high impact collaborative care 

interventions as a group. We also aimed to identify a short list of features that, when present, are 

associated with greater intervention impact. We additionally identified a set of “optional” features 

that varied across studies but were not associated with differential outcome effects. A short list of 

such features can assist those implementing collaborative care as a depression quality improvement 

strategy to choose intervention designs (or change strategies, in quality improvement terminology) 

with the greatest probability of reproducing the effects of high impact depression care interventions 

from the literature. Finally, we aimed to add to our current understanding of how to use literature 

analysis to understand multi-component interventions by using innovative qualitative approaches 

to overcome some of the methodological limitations of meta-regression for understanding how to 

implement successful depression collaborative care interventions.

The rationale behind supporting these aspects of depression care delivery is strong, in that 

depression quality of care is known to be suboptimal in each of these areas, and better 

performance relative to them is associated with improved outcomes (Hepner, Rowe et al. 2007). 

To date, collaborative care approaches remain the only identified method for enhancing guideline 

concordance, and improving outcomes, in primary care. It is thus essential for primary care 

and mental health specialist managers to know which features of collaborative care research 

interventions are necessary for achieving effects.

Our study builds directly on a prior literature synthesis recently published by Williams et al. This 

study aimed at identifying features of collaborative care, but did not carry out quantitative or 

rigorous qualitative analyses to determine relationships between features and study outcomes. 
11

The data set assembled by this study, however, provides a rigorously identified set of high quality 

collaborative care articles that follow a chronic illness care model. The authors assembled, in 

addition, a rich set of over 60 rigorously defined variables, of which 22 related to specific broad 

intervention or evaluation features. By using this set as a starting point, we aimed to focus this 

study intensively on understanding the links between features and outcomes. 

While previous meta-analyses were aimed primarily at determining whether collaborative 

care models, loosely defined, were effective, Williams aimed specifically to understand 

collaborative care features. He and colleagues therefore selected a group of articles that were 

more homogeneous in design (all randomized trials) and that focused on an organizational 

intervention aimed at patients (eliminating studies limited to staff level interventions only, 

such as education or reminders). Selected studies (a) involved primary care patients receiving 

acute-phase treatment; (b) tested a multicomponent intervention involving at least one patientdirected component; and (c) reported effects on depression severity. Reviewers analyzed the 28 

multifaceted organizational interventions meeting these criteria according to intervention features 

mapped to the Chronic Illness Care Model (Wagner, Austin et al. 2001). Reviewers sought 

further unpublished details from study authors as needed. 

The review found that all selected studies involved care management and required additional 

resources or staff reassignment to implement. The other most commonly used features among the 

studies included: patient education and self-management, monitoring of depressive symptoms and 

treatment adherence, decision support for medication management, a patient registry and mental 

health supervision of care managers. Additional intervention features were highly variable. Overall, 

the set of studies selected confirmed prior meta-analysis results, showing significant short-term 

effects of collaborative care up to 12 months and with three studies showing longer-term effects (up 

to 57 months). No quantitative analyses relating features to outcomes were performed, however. 

The study concluded that there was strong evidence supporting the benefits of care management for 

depression, but only “emerging” evidence on what constituted a successful care management model.

Methods

Topic Development

The Veterans Health Administration (VHA), along with many other health care organizations 

and primary care practices, aims to improve care for depression among primary care patients. 

VHA participated in the President’s New Freedom Commission, and developed mental health 

strategic priorities related to improving mental health care in primary care in 2004 based in 

part on the Commission’s report. Following the strategic plan goals, beginning in 2006, VHA 

began a series of initiatives focusing on primary care/mental health integration, funded at high 

levels and culminating in a mandatory Uniform Mental Health Services Package for mental 

health conditions (VHA Handbook 1160.01). In beginning the improvement process, VHA 

researchers and policy makers identified the need to understand in more depth which of the 

features of previously tested multifaceted depression care interventions might be considered 

optional, and which should be considered required based on their impacts on outcomes. Required 

features could be incorporated into guidelines or best practices for improvement, and could be 

targeted for particular attention, tools, and other resources during the implementation of the 
12

improvements in new organizations and practices. 

Our main research question was whether, based on the literature, there are specific features 

of rigorously evaluated depression care improvement interventions that characterize effective 

interventions or are associated with greater intervention impacts. As a secondary research 

question, we asked whether there were specific design features of the practice settings or of the 

evaluation designs in these studies that might be associated with consistently greater or smaller 

effects. We also assessed effects of patient complexity on intervention effectiveness.

Methodological Overview 

In this study, we used the Williams review (Williams, Gerrity et al. 2007) as the basis for further 

investigation of relationships between intervention features, study designs, and outcomes. 

We used the 28 selected studies, and the 22 specific variables already abstracted to describe 

intervention or evaluation features, as the basis for quantitative evaluation. We developed 

hypotheses about features most likely to affect outcomes, and used existing variables, derived 

variables based on them, or new variables created for this review to address these hypotheses. 

We re-abstracted articles and queried authors to complete new variables. All new variables 

represented independent review and consensus among three investigators (JW, LR, MS). 

After reviewing quantitative results, we used qualitative cross-case impact analysis (Miles 

and Huberman 1994) iteratively with quantitative regression analysis to refine our results and 

develop a short list of key intervention features.

Search Strategy 

The search strategy used in the Williams review (Williams, Gerrity et al. 2007) is listed below:

DATABASE SEARCHED & TIME PERIOD COVERED:

We searched Medline, HealthSTAR, CINAHL, PsycINFO and a specialized registry of 

depression trialsfor English-language medical literature published from 1966 to February 

2006

LIMITERS:

SEARCH STRATEGY: Search terms included: (a) the MESH terms “depressive disorder” 

and “depression”; (b) a series of terms validated to identify clinical trials; and (c) a series of 

MESH terms and text words designed to identify studies using one or more elements of care 

management (Appendix A). Other sources were references identified from pertinent articles 

and contacts with experts in the field of depression and health services interventions. Exact 

search terms are reported in (Williams, Gerrity et al. 2007).

In addition to our PubMed search, we performed reference mining of retrieved articles, 

references of prior reviews, and solicited articles from experts.

NUMBER OF ITEMS RETRIEVED: 1464
13

Study Selection

Of 1464 articles identified, reviewers from the Williams study (Williams, Gerrity et al. 2007) 

identified 138 as potentially relevant. These were reviewed to identify randomized controlled 

trials meeting the following selection criteria: (a) samples comprising adult patients with a 

depressive disorder who were cared for in a primary care setting; (b) interventions needed to 

augment usual care by incorporating at least one patient-directed element from the CCM (e.g., 

patient self-management, active follow-up); and (c) studies had to report clinically meaningful 

outcomes, such as change in depressive symptoms. Inter¬ventions directed solely at the clinician 

(e.g., clinician education or performance feedback) or health care system (e.g., automated 

clinical reminders) were not included. Twenty-eight of the 136 articles met these criteria. 

Data Abstraction 

Our final set of key intervention variables, and their definitions, is listed in Table 1. Some 

variables are from the original Williams study (Williams, Gerrity et al. 2007). Others are based 

on either re-derivation or re-abstraction as a part of this study. Table 1 provides the variable 

labels, names and definitions for the major analytic variables. It also indicates whether the 

distribution of each variable was adequate for regression analysis (at least 3 studies per variable 

value) at each time period (short-term, medium-term or long-term). Variables measuring nonwhite status and comorbidity are listed in Table 7 only.

Variable Definition and Abstraction in the Williams Study: In the Williams study (Williams, 

Gerrity et al. 2007) pairs of independent reviewers (SKD, AJD, JWW, JD, TH, BNG) abstracted 

the 28 articles to identify features of the chronic illness care model (Wagner, Austin et al. 2001; 

Bodenheimer, Wagner et al. 2002; Bodenheimer, Wagner et al. 2002); study clinician and patient 

characteristics; 3) components of the intervention (decision support, self-management support, 

delivery system redesign including care management and enhanced mental health involvement, 

and clinical information systems), and support for implementing the intervention; 4) care 

management functions and process, and 5) outcomes. When key information was missing or 

unclear, investigators contacted the primary author for clarification; 22 of 24 authors contacted 

responded to our request. Two investigators (MSG, JWW) reviewed areas of disagreement. Final 

classification was based on the consensus of all investigators. 

Data abstraction included study design features, including inclusion and exclusion criteria, and 

proportion of minorities in the study. The study also focused substantially on care management, 

defined as any systematic or structured management of patient care by a designated provider, and 

on patient outcomes. Specific abstracted features on care management included coordination and 

communication among treating health care providers, patient education, monitoring symptoms 

and adherence to treatment plans, self-management support, or psychological treatments (Katon, 

Von Korff et al. 2001; Oxman, Dietrich et al. 2002). Outcomes abstracted included the proportion 

of subjects who had a least a 50% decrease in depressive symptomatology or remission in 

symptoms based on a validated questionnaire, the mean change in depressive symptoms, and 

antidepressant adherence. Extensive variable tables are included in the Williams publication.
14

Study Intervention and Evaluation Variable Definition and Abstraction (Current Study): We 

reviewed, re-abstracted or re-defined variables from the Williams study related to four categories 

relevant to our research questions. The first category focused on study intervention features and 

patient characteristics. The second category focused on intervention features. The third category 

focused on measures of study impact, including depression symptoms, patient adherence to 

treatment, satisfaction, and global improvement or functioning. The fourth category focused on 

study design characteristics, including proportion of patients who were non-white, and inclusion 

and exclusion criteria.

We then derived ten new variables. Five of the new variables required re-abstraction of the 

article set, while the other five were new combinations of previous variable values. Variables 

we re-derived and/or re-reviewed included those related to 1) care management (defined 

as any systematic or structured management of patient care that included coordination and 

communication among treating health care providers); 2) patient education; 3) self-manage¬ment 

support or psychological treatments; 4) monitoring of symptoms; 5) monitoring of adherence to 

treatment plans, and 6) impact. 

We contacted authors for additional information as needed. Overall, between the original data 

collection and our final data collection effort, we attempted to contact all but two of the authors, 

and succeeded in getting a responses from all but one of those we attempted (26/28). We got 

information from each of these authors between one and four times (mean 2.1). Only one of the 

authors contacted was unable to supply the information we needed. In both the original and final 

data collection efforts, two investigators independently abstracted the articles and reviewed any 

area of disagreement. Final variable values in the original data set were based on the consensus 

of all investigators on that article, and in our additional data collection were based on consensus 

of two authors (Williams and Rubenstein). For final analyses, a third author (MS) reviewed 

variables we identified as significant. 

Study Outcome Variable Definitions and Abstraction: We used effect sizes for depression 

symptom change and relative risk of depression resolution as our main outcome measures. Our 

statistician for this study (MS) independently abstracted the data needed to calculate both effect 

sizes for the continuous outcomes and risk ratios for the dichotomous outcomes.

Our symptom outcome variables identified all reported effect sizes in short (six weeks to four 

months), medium (five to eight months), and long (nine to twelve months) time strata after 

baseline. We developed one set of outcome variables with values at these time periods based on 

continuous symptom measures, and another set based on dichotomous outcomes. 

Examples of continuous outcomes include results based on depression scales such as the Beck 

Depression Inventory, Hamilton Depression Rating Scale, or Hopkins Symptoms Checklist-20). 

Examples of dichotomous outcomes include assessments of the percent of patients recovered or 

below a specified symptom threshold by the end of the study. 

After initial hypothesis testing, we developed and validated a newly-developed impact scale 

for subsequent qualitative and quantitative analyses. Because studies used different symptom 

measures and different follow-up time periods, each outcome variable based on effect size 
15

included only a portion of the articles in the set. To create an outcome measure applicable to all 

articles in the set, we developed an impact rating for each article. 

To derive the impact measure, we randomly ordered the 28 studies on an Excel spreadsheet 

and listed only each study’s set of outcomes, without any other identifiers. We listed all of the 

measured outcomes for each study that fell into one of four conceptual domains. These were 

depression symptom outcomes, process of care outcomes (usually adherence to antidepressants), 

patient satisfaction, and quality of life or functioning (see table below). For each outcome we 

listed whatever statistics the authors reported. Two authors (LR and JW) then independently 

reviewed and rated the outcomes on the scrambled Excel spreadsheet, independently of any 

article identifiers. One investigator (JW) rechecked using outcomes from Table 4, Williams 

(Williams 2007). Considerations for assigning impact level included consistency of results 

across domains, size and significance of the effects, and persistence of results over time. The 

rating process graded impacts on a four-point scale as robust (high), medium, low, and none or 

negative. Interater reliability for impact judgments was high, with agreement on 86% (24/28) 

of ratings. Final impact ratings reflected consensus on the four studies rated differently. The 

example table below shows four actual example studies with their impact ratings. 
16

Example Table for how impact ratings were carried out

Example 

Studies 

Treatment 

Adherence

(short-term)

Treatment 

Adherence

(medium 

term)

Depression 

Symptoms

(short term) 

Depression 

Symptoms 

(medium or 

long term)

Satisfaction Global or 

Functional 

impact

Impact Rating By LR, 

JW

Information 

recorded for 

each study, 

as available. 

Usual care 

group noted 

first vs. 

intervention 

group 

E.g., odds 

ratios, significance, what 

was measured, 

time measured

E.g., odds 

ratios, 

significance, 

what was 

measured, 

time measured

 E.g., odds 

ratios, change 

scores, 

significance, 

patients with 

50% symptom 

decrease, type 

of measure, 

E.g., odds 

ratios, change 

scores, 

significance; 

patients with 

50% symptom 

decrease; 

type of measure

E.g., odds 

ratios, percent 

satisfied, significance, time 

measured

E.g., odds 

ratios, 

significance, 

what was 

measured

Robust, 

Moderate, 

Weak, Little or 

No Impact

#1 --- ---- -3.9 vs -5.6, 

p= .02, Ham-D 

change, 3 

mos.

-4.0, vs -7.3 

p<.001, 

Ham-D 

change, 6 

mos.

33% vs, 

53% p<.001, 

Ham-D 50% 

improvement, 

at 12 mos.

---- P < .05 on 

the SF 20 

at 12 mos., 

exact score 

not given

Robust

#2 957 vs 867, 

NS, 

Mean 

milligrams 

antidepressant 

dispensed at 

6 wks

2267i vs. 2111, 

NS, Mean 

milligrams 

antidepressant 

dispensed at 

6 mos 

33% vs 38%, 

p=.01, Ham-D 

50% improvement, at 6 

weeks

33% vs 38%, 

NS, Beck 50% 

improvement, 

at 6 wks.

38% vs. 

57%, p=.003, 

Ham-D 50% 

improvement 

at 6 mos.

37% vs. 48%, 

p = .05, Beck 

50% improvement at 6 

wks.

3.94 vs. 4.20, 

p=.001, 11 

item unpublished scale, 

at 6 mos.

44.6 vs. 

47.3, p = .10, 

SF-12 MCS 

score at 6 

mos.

Moderate

#3 -- 42% vs 64%., 

p<.001, 

prescribed >90 

days AD

1.5 vs. 1.58, 

NS, SCL-20, 

at six months

1.63 vs. 1.62 

NS, SCL-20, 

at six months

--- 31.7 vs. 

31.1, NS, 

PCS from 

SF36V

Weak

#4 No significant 

difference at 

3 mos. (no 

numeric data 

provided)

30% versus 

49% adherent 

to anti-depressants, p <.05, 

at six months 

excluding 3 

dropouts, NS 

for intent to 

treat

21% vs. 21% 

50% improvement, NS, 

BDI, 3 mos.

--- --- ---- Weak
17

Study Quality assessment 

Determination of study quality was based on the Williams study. The quality measure took 

account of the process of randomization and allocation concealment, fidelity to the planned 

intervention without significant co-intervention, follow-up rates and analytic methods, using an 

intent-to-treat approach and blinded outcome assessments. Based on these criteria, risk of bias 

was rated as a low (all elements met), moderate (> 1 element partially met), or high (> 1 element 

not met) (Higgins and Green). There were no disagreements about quality assessments. 

Data Synthesis and Analysis

Correlations: Prior to carrying out regression analysis, we evaluated correlations between 

intervention and evaluation design features. Since intervention and evaluation features were 

categorical, we evaluated the correlations between variables using cross tabulations and the chisquare statistic. 

Effect Size Calculations for Continuous Outcomes: In order to compare estimates across studies 

that report different depression scales, the effect size was selected as the unit of analysis. An 

effect size was calculated if the follow-up mean, standard deviation, and sample size for both 

the intervention group and usual care group were reported or could be calculated. For trials 

that reported a mean outcome but no standard deviation, the standard deviation was estimated 

by taking the mean standard deviation weighted by the sample size across all other trials that 

reported standard deviations for that outcome (Furukawa, 2006).

Only one comparison per study within each time strata was calculated. For studies that included 

more than one intervention group, the group that was most similar to the complete collaborative 

care model was included. In addition, only one outcome per study was used. If a study reported 

more than one depression scale, then the measure that was clinically homogeneous to the scales 

reported in the other included studies was selected. Effect sizes were calculated by dividing the 

difference of follow-up means of the intervention and control group by the pooled follow-up 

standard deviations of the two groups (Sutton AJ, 2000). Ninety-five percent confidence intervals 

were calculated for each effect size. A negative effect size indicates that the intervention group 

did better at follow-up than the control group. Negative effect sizes indicate benefit because 

when the intervention group is doing better than the control group, depression symptoms are 

reduced. Thus, for example, for each independent variable, the largest negative effect size shows 

the group with the greatest effect. 

Risk Ratio Calculations for Dichotomous Outcomes: We estimated a risk ratio to assess effect 

for dichotomous variables. For the risk ratio analysis, we used the longest follow-up interval 

reported. Risk ratios and their ninety-five percent confidence intervals were estimated for studies 

that reported the percent of people who improved since baseline in each study. A risk ratio greater 

than one indicates that the intervention group had a higher rate of improvement than the usual 

care group did. For example, a risk ratio of 1.50 signifies that 50% more people improved in the 

intervention group than in the usual care group. All analyses were conducted in Stata version 10.0.
18

Quantitative analysis focused on assessing key independent variables related to evaluation 

or implementation design against depression symptom outcomes as the dependent variable. 

Correlations between the independent variables were assessed. A stratified meta-regression was 

conducted separately for each independent variable with the effect size as the outcome (Sutton 

AJ, 2000). Stratification was based on follow-up time. A study could contribute to more than one 

stratum. Bivariate meta-regressions using the same independent variables as above were also 

conducted using the risk ratio as the outcome. Estimates were obtained from the meta-regessions 

for each level of the independent variable. In most cases, the independent variables had two 

levels (e.g. did the study have the component or not). A z-test was used from the meta-regression 

to test if the difference in effect sizes or risk ratios was significant between component groups. 

Differences with p-values less than 0.05 were denoted (Stata, 2006).

In this study, we found variations in which outcomes were used, ranging from a variety of 

depression symptom indices, health-related quality of life, patient satisfaction, and process of 

care for depression. We also found variations in when outcomes were measured. We used a 

conservative analytic approach such that we focused on depression symptom outcomes only. We 

also focused on time frames separately, rather than combining results across time frames. 

Qualitative Analysis

We carried out qualitative cross-case analysis using methods based on Miles and Huberman 

(Miles and Huberman 1994). We used this approach to overcome limitations to meta-regression 

in our article sample—primarily the inability to include all 28 selected articles in a single metaregression analysis. In traditional meta-analysis, the study intervention is treated as the same 

across all studies. The major challenges posed during this kind of analysis derive from variations 

in how outcomes are reported (e.g. by time period, or specific measure); these variations may 

limit the number of studies included in a given analysis. However, since each study is included 

as a whole, power for detecting overall effects with an article sample size like ours is generally 

adequate. Meta-regression, however, makes comparisons within the overall group of studies and 

is thus more analytically demanding. In addition, valid meta-regression using multiple features 

or control variables simultaneously would require more studies than were available to us. Since 

no single quantitative outcome analysis in this study included all reviewed studies, we wanted 

to confirm qualitatively that our quantitative results were insensitive to inclusion of all studies 

in the same outcome analysis. We also wanted to be able to assess intervention features that 

characterized too many studies in the sample to be tested quantitatively (see Table 1). Cross-case 

analysis afforded us the ability to achieve these goals.

To carry out the analyses, we ranked studies by impact level based on our overall impact measure 

(see above). We focused primarily on the intervention features that had inadequate distributions 

either at all time periods or at medium-term and long-term due to being present in too many 

studies in the sample (see Table 1). These intervention characteristics could not be adequately 

tested quantitatively. We also developed four main scenarios based on our hypotheses for 

types of interventions or design features and their relationships to impact. We then created a 

series of tables around these scenarios as antecedent matrices related to our conceptual model 

of collaborative care and our hypotheses about effects of study design features. We looked for 
19

patterns, and verified scenarios for similar and contrasting outcomes. 

Peer Review 

This report was reviewed by our technical experts. Their comments were taken into consideration 

in our revision. Service as a technical expert does not imply endorsement of the report’s findings. 

A table of peer review comments received and the changes we made to the report is presented in 

Appendix B.
20

Results

Literature Flow 

Of 138 studies reviewed, 29 met all inclusion criteria (Fig. 1). One of these was excluded 

because the intervention targeted relapse prevention for patients in remission from a depressive 

episode. Twenty-eight studies were reviewed for further analysis. Reviewers also consulted fiftysix articles that were companion papers for included studies and described methods, long-term 

outcomes, subgroup analyses, cost data and other outcomes. 

Among the 28 selected studies, overall study quality was high (Table 2 and Appendix A). Risk of 

bias was low in 18/28 studies (64%); moderate in 6/28(22%); and high in 4/28 (14%). Outcomes 

were assessed blind to treatment assignment in 23 studies, and intent-to-treat analyses were used 

in 21 studies. Fifteen of the 28 studies (54%) involved managed care practices, including five in 

Veterans Affairs facilities. Most were carried out in the United States. 

Studies Included in Effect Size or Relative Risk Analyses

Twenty-five of the 28 studies included usable continuous depression symptom measures for 

analysis, while three studies did not. Two of the excluded studies did not report a follow-up 

mean, and one did not report the sample size by group. Among the 25 studies in the continuous 

measure analysis, 21 included effect sizes based on short-term follow-up. Eighteen studies 

contributed intermediate-term effect sizes. Ten studies contributed long-term effect sizes. 

Eighteen studies reported a dichotomous improvement outcome and were included in the risk 

ratio analysis. 

Four studies had two intervention arms and reported results for each arm separately. For Katon 

(1995) and Katon (1996) the major depression groups were used while the minor depression 

groups were excluded. Simon (2004) reported two intervention groups. Both had telephone care 

management. One group had the addition of telephone psychotherapy which was the intervention 

group we selected to compare against the usual care group. Simon (2000) had feedback only and 

care management – we selected the care management group to compare to the usual care group. 

For Wells (2000), the enhanced medication arm was used.

We found that not all studies could provide suitable information for each effectiveness analysis. 

We found that studies were too heterogeneous in their assessments of comorbidities and 

demographics to evaluate any of these variables quantitatively. We were, however, able to 

evaluate studies with a higher proportion (over 25%) minorities. 6 studies did not report minority 

status.

Correlations between Features

When we evaluated correlations between the intervention and evaluation features used in our 

final analyses, we found that enrolling patients through primary care clinician referral of patients 

or by identification of patients on antidepressants (versus by screening) is significantly correlated 
21

with use of patient level randomization (p = .03). Enrolling patients referred by primary care 

clinicians on antidepressants or willing to take them is correlated with study inclusion of fewer 

practice groups.(p = .01). Having mental health specialists involved in patient management was 

also correlated with inclusion of fewer practice groups (p = .03). 

Looking just at collaborative care model intervention features, we found that studies in which 

medications were adjusted by primary care clinicians with expert guidance were significantly 

more likely to include care managers who were nurses, versus other types of professionals; were 

more likely to include at least 16 weeks of follow-up (p = .04); used more intensive (robust) 

interventions (p = .001); and followed an overall classic collaborative care intervention model 

(p = .04). Classic collaborative care interventions were correlated with having a dedicated care 

manager who used standardized depression symptom scales for follow-up (p = .03). Including 

active self-management was correlated with having a dedicated depression care manager who 

assessed depression symptoms with a structured instrument at baseline and at one or more 

follow-up visits, and who also assessed treatment adherence (p = .02). 

No other correlations (associations) between study variables shown in Table 1 were significant at 

p <.05.

Overall Effectiveness

Overall, the experimental groups in selected studies showed improvement. The overall effect size 

by follow-up time was: short-term, -0.28 (-0.38, -0.19); intermediate term, -0.25 (-0.37, -0.14); 

and long-term, -0.19 (-0.36, -0.02). Twenty of 28 interventions improved depression outcomes 

over 3–12 months (an 18.4% median absolute increase in the proportion of patients with 50% 

improvement in symptoms; range, 8.3–46%). 

Study Evaluation Design Features vs. Effectiveness

Study designs varied on several major features. Subjects were recruited using four strategies: 

screening (n =11), clinician referral (n =9), administrative or pharmacy databases (n =3), a 

combination of these strategies (n =3) or direct contact by a pharmacist when an antidepressant 

prescription was filled (n =2). The unit of randomization varied across studies: 18 randomized 

patients, 3 randomized providers and 7 randomized practices.

Table 3 shows the relationship between four evaluation design features and depression symptoms 

and resolution, using univariate regression. In the table, the group with the higher negative effect 

size shows greater reduction in depression symptoms, and the group with the higher relative risk 

shows a better chance of depression resolution. Because nearly all studies had some effect, effect 

sizes both with and without the target feature are negative (showing an effect on depression 

symptoms), and nearly all relative risks are greater than one (showing greater resolution of 

depression). We report results on short-term, medium-term, and long-term outcomes. Our results 

show that studies in which patients were referred to care management through screening, rather 

than by primary care clinicians or administrative medication records, had a significantly higher 

relative risk of depression resolution. No other among the four design features we investigated 

was significantly linked to outcomes.
22

Table 3 also shows that studies with greater than 25% minorities tended to show greater effects, 

although this difference did not reach statistical significance. Six studies did not record minority 

status.

Associations between Intervention Features

and Outcome Effect Sizes

Table 4a shows the relationship between nine variables reflecting collaborative care model 

intervention features and depression symptoms and resolution. In the table, the group with the 

higher negative effect size shows greater reduction in depression symptoms, and the group with 

the higher relative risk shows a better chance of depression resolution. We report results on shortterm, medium-term, and long-term outcomes. Initial univariate regression results evaluating 

the first five individual features listed in the table (structured care manager assessment, active 

self-management support, care manager triage to mental health, adjustment of antidepressants 

by primary care clinicians, and care managers who were predominantly nurses) showed active 

patient self-management support as the single statistically significant intervention characteristic 

associated with improved depression symptoms and depression resolution. 

We then derived additional variables shown in Table 4b. This table shows that studies with 

nurse or PhD pharmacist care management, patient education, and at least sixteen weeks of care 

manager follow-up (classic collaborative care model with long-term follow-up, see variables 

Table 1) are associated with significantly improved long-term effects on depression symptoms. 

Having at least 16 weeks of care manager follow-up alone was not well-distributed as a variable, 

but appeared to be associated with a significantly greater reduction in depression symptoms at 

short-term and medium-term time points. 

Impact Measure

We designed our study impact measure to distinguish between high, medium or low impact by 

the study intervention by qualitatively taking into account all key outcome variables comparing 

intervention to usual care and all measurement time periods. We therefore expected it to be 

associated with, but not identical to, our quantitative study effect size measures of depression 

symptom reductions. Though the impact measure was based on expert rating, it was significantly 

associated with quantitative depression symptom effect size results at each time point (Table 5). 

Based on quantitative depression symptom reduction effects, the impact measure statistically 

distinguished studies designated as showing high, medium, or low impact from those designated 

as showing little or no impact. The impact measure was also associated with significantly greater 

relative risk of depression resolution. However, unlike the effect size measures we used for our 

primary study outcome tests, and as discussed in the Methods section above, the impact measure 

could be applied to all 28 studies. This afforded us additional opportunities to evaluate our 

results, and test their sensitivity to inclusion of all studies together. 

Qualitative Analysis of Intervention Features Versus 

Outcome Impacts

To understand our initial regression results, we carried out extensive cross-case analyses looking 

at combinations of characteristics versus our impact measure, based on a priori study questions 
23

as indicated in Methods above. Table 6 shows cross-case analysis of our key collaborative care 

model intervention features. The cross-case analyses enabled us to look closely at features that 

occurred together in large proportions of higher impact studies (the 20 studies with high, medium 

or low impact versus the 8 with little or no impact). We considered features present in 80% or 

more of the higher impact studies to be core features of effective collaborative care models. Our 

analyses identified six collaborative care model intervention core features. These were: 

○ Primary care clinicians actively involved in patient management

○ Mental health specialists actively involved in patient management

○ Care managers assessed patient symptoms at baseline with a standardized scale

○ Care managers assessed patient symptoms at follow-up with a standardized scale

○ Care managers assessed treatment adherence at follow-up 

○ Collaborative care intervention included at least 16 weeks of active patient follow-up

As shown in Table 6 and, in greater detail, in Table 9, active patient self-management support 

strongly characterized the high and medium impact studies, and became less prevalent in the low 

and little or no impact groups. Only one high impact study and only two medium impact studies 

did not undertake active self-management support. The one high impact study without active 

patient self-management (Katzelnick, Simon et al. 2000) used a previously tested and validated 

educational tool. 

As indicated in Table 6, there were five VA studies in the sample, and one additional study with 

a VA site. Among the studies conducted in Veterans Affairs facilities, those that supported active 

patient self-management (Oslin, Sayers, Ross, et al., 2003; Fortney, Pyne, Edlund, et al., 2006) 

had the higher impact scores. One study (Swindle) that had low impact used mental health 

clinical nurse specialists as care managers and did not include structured assessment. A second 

low impact VA study (Dobscha) did not include at least twelve weeks of follow-up.

Table 9 shows the details of the self-management support interventions used in these studies. 

While all included studies incorporated at least one chronic illness care element directed toward 

patients, this element might be, for example, care manager assessment without patient education 

and behavioral activation. We looked for self-management support approaches that featured 

behavioral activation or interactive problem-solving approaches, usually in addition to standard 

patient education using written material or videotapes. We counted CBT provided by mental 

health specialists as therapy rather than self-management support.

In addition to core features, we used qualitative analyses to identify features that varied across 

high impact studies, and could thus be considered options. The main feature that emerged as an 

option was telephone versus in person care management.
24

Qualitative Analysis of Evaluation Design Features, Including Patient Comorbidity, Versus Outcome Impacts

Table 8 shows qualitative results for evaluation design features. We found no evaluation 

design features other than those related to comorbidities that characterized more than 80% of 

high impact studies. In general, studies conducted in Veterans Affairs facilities were mediumsized, randomized at the provider or practice level, and eligible patients were referred through 

screening.

Table 7 shows results for comorbidities and demographics versus impact. More than 80% of 

studies excluded patients with bipolar disorder and psychosis. No study excluded anxiety. Six 

studies (21%) did not mention PTSD, and only 14% of the remaining 22 studies excluded 

patients based on it. Most studies (18 of the 28) excluded patients with substance abuse. Six 

studies (21%) did not report on the proportion of minorities enrolled. 

In evaluating the relationship between evaluation design features and outcomes, we found no 

consistent effects qualitatively for the following design variables: number of practices in the 

study, patients per practice, whether patients were screened by the study and referred or were 

referred by their clinicians, or whether randomization was at the patient or cluster level. 

Limitations

The results of this review are limited by several important factors. First, the analyses conducted 

in this paper were not designed to address causality. Even the quantitative analyses must be 

considered descriptive, and the qualitative analyses are hypothesis-generating. The number of 

categories of analytic variables tested and the possibility of misclassification of variables across 

reviewers have the potential to bias our results. With only 28 articles, quantitative analyses are of 

necessity limited. Nevertheless, within the framework of a set of complex interventions that we 

already know have robust effects on depression outcomes, but that vary in basic components, our 

analyses have substantial strengths. Strengths of our analyses include our extensive querying of 

authors regarding intervention and evaluation features; our systematic approach to analysis; our 

rigorous variable definitions and validation through independent review and consensus; and our 

triangulation, or sensitivity testing, of conclusions across methodologies. 

Our qualitative approach is hypothesis generating. Our impact score is subjective, although 

rigorously derived and associated with effect sizes at each time frame. However, the only 

quantitative approach to defining an outcome across all 28 studies would have been to combine 

effects across heterogeneous time frames and measurement methods, an approach that may 

have resulted in greater bias than the method we chose. Future studies could assess the tradeoffs 

between these approaches. Our analysis is based on iterative review of data by investigators, and 

thus subject to bias. Our use of rigorous cross-case methods mitigates, but does not eliminate 

this possibility. The transparent presentation of our analyses to readers in tabular form, however, 

should assist readers in making independent assessments of our conclusions. 
25

The studies upon which we based our analyses also have limitations. The studies themselves 

have selection biases. Even studies that use screening to identify patients exclude some 

categories of patients and recruit only a portion of those eligible due to refusal. We therefore 

cannot be certain how well these studies generalize to use of the collaborative care model in 

usual practice settings. Most interventions in these studies were imple¬mented through large 

health care organizations, limiting the generalizability of the results to organizations with 

sufficient structure, commitment and resources to imple¬ment interventions requiring changes 

in systems of care. Moreover, practices in fee-for-service environments that do not reimburse 

for care management services have fewer incentives for implementing these interventions. In 

addition, there may be contextual variables not measured in the studies that influence outcomes. 

For example, even within managed care organiza¬tions, Rubenstein et al. (Rubenstein, Parker 

et al. 2002; Rubenstein, Meredith et al. 2006) found that expert leadership and support from 

local practice management and mental health specialists influenced the development of 

successful programs. In addition, study comparisons were to usual care. Usual care, however, is 

heterogeneous across settings and providers, For example, some usual care settings may have 

ample mental health specialty access, while some have little.

In terms of the interventions studied, we could not test the independence of many of the features 

in association with outcomes because the features were not distributed evenly among studies. 

Some features also tended to occur with other features. We extensively tested combinations of 

features both in quantitative analysis (e.g., the classic collaborative care model) and in qualitative 

analysis, where features could be viewed as present or absent across studies. 

Our study is limited in terms of shedding light on the chronic illness care model as applied 

to conditions other than depression. Depression has unique features that might make it more 

necessary to expend resources on, for example, care management. Depressed patients tend 

to be apathetic, poor consumers who benefit from proactive care. They are often not detected 

without screening. Screening requires psychological testing, rather than a blood test, and followup of positive screens requires either a full mental health specialist interview or psychological 

assessments using standardized tests that take in the neighborhood of 40 minutes to complete. 

Assessment is difficult to complete in an average 20 minute primary care visit. Assessment can 

additionally uncover serious urgent or emergent conditions such as suicidal threats, requiring 

additional time to handle appropriately. Furthermore, adherence to treatment is likely to be a 

more prevalent problem among depressed patients than among other chronically ill patients. 

Follow-up care requires frequent contact, but not full in-person visits—the interview, not the 

physical examination or laboratory testing, provides most of the necessary information. Finally, 

mental health specialists may be more organizationally or geographically separate from primary 

care than are other specialists. The unique characteristics of depression may thus help explain 

why there is substantially more evidence for cost-effectiveness of depression collaborative 

care than for other care management-based interventions. Future research will clarify the 

transportability of conclusions on depression collaborative care to other chronic conditions.

The studies on collaborative care for depression were also severely limited in terms of 

addressing medical or psychiatric comorbidities. No evidence is available from these studies 

on collaborative care for bipolar disorder or psychosis, because these patients were nearly 
26

universally excluded. Patients with subthreshold depression were also usually excluded, although 

one of the studies later found evidence of positive effects among these patients (Wells 2005). 

Only a few studies included patients with substance abuse. Among the studies that included a 

broader group of patients, intervention protocols most likely specified referring patients with 

severe psychiatric comorbidities for mental health specialty care (e.g., RAND 2000). Thus, no 

conclusions can be drawn from this review on collaborative care for primary care patients with 

medical or psychiatric comorbidities.

This study identified only 28 studies out of 1464 that met full inclusion criteria, and less than 

half of these were published in the last five years. Previous collaborative care literature syntheses 

have netted 30 to 40 includes, but have included more heterogeneous groups of interventions 

and evaluations. New methods for achieving the necessary improvements in depression care may 

well be identified in future reviews. 

Conclusions

While collaborative care models for depression vary, careful analysis of model features shows 

that a core set of characteristics is linked to better results. This set is robust across qualitative 

and quantitative analyses, and does not seem to be biased by links to particular evaluation design 

features (e.g., the design feature of randomization at the patient level is distributed across all 

levels of care model impact). In addition to the core variables, active patient self management 

support appears to characterize the set of very high impact studies. These finding are sufficiently 

strong to support recommendations to sites intending to implement collaborative care for 

depression.

Guidelines for sites intending to implement collaborative care for depression should identify 

primary care and mental health specialty clinician involvement; care manager assessment of 

symptoms at baseline and follow-up using a structured instrument; care manager follow-up 

assessment of treatment adherence; and active follow-up for at least 16 weeks as core features of 

current evidence-based models. Guidelines should further recommend inclusion of active selfmanagement support, such as elements of patient activation, cognitive behavioral or problemsolving therapy, or motivational techniques, for additional improvement in outcomes.
27

figure 1. article flow 

relevant studies (n = 138) 

 

.

potentially relevant 

rCts (n = 29)

potentially relevant rCts 

 (n = 123) 

included in the 

systematic review 

rCts (n = 28) 

Studies excluded because not RCTs in adults 

(n=15)

RCTs excluded because not done in a 

primary care setting (n = 7) or did not include 

a patient-directed component (n = 25) 

potentially relevant rCts 

 (n = 91) 

RCTs excluded because they were companion 

papers for those included (e.g., description of 

methods, long-term outcomes) (n = 56) 

RCT excluded because it targeted 

relapse prevention (n = 1) 

Fig. 1. Flow diagram of the search and selection processes for trials 

included in the systematic review. 
28

Table 1: Variables Characterizing the Study Intervention and Design

Variable Name Variable Definition and Distribution†

Number of Practices in the 

Study 

(practice group = small, medium, or large)

Number of practices in the study. There are three levels: 

Small (1-2); Medium = (3-10); Large = (>10). (categorical)

Distribution adequate for short-term and intermediate-term. 

Inadequate for long-term based on too few “small” category 

studies.

Referred to the Study by 

Primary Care Clinicians or on 

Antidepressant Medications

(type_ref1=yes)

Patients enrolled in the study were referred by primary care 

clinicians and/or were on antidepressant medications. All 

other studies screened patients for depression, and included 

those who screened in as probably depressed. (dichotomous)

Distribution adequate for short-term, intermediate-term and 

long-term.

Referred to the Study by Primary Care Clinicians and on 

Antidepressant Medications 

or Willing to Take Them.

(type_ref2=yes)

Patients enrolled in the study were referred by primary care 

clinicians and were on antidepressant medications or indicated a willingness to start them.

Distribution adequate for short-term and intermediate-term; 

inadequate for long-term based on too few “yes” category 

studies.

Study Set in Primary Care 

Clinician Offices

(type_set=yes)

Study set in primary care clinician offices rather than in a 

community-based setting. (dichotomous)

Distribution not adequate for short-term, intermediateterm or long-term based on too few “no” category studies.

Patient Level Randomization

(rand1=yes)

Subjects were randomized at the patient level rather than at 

the provider or practice level (dichotomous)

Distribution adequate for short-term, intermediate-term and 

long-term.
29

Variable Name Variable Definition and Distribution†

Structured Care Manager 

Assessment of Depression 

Symptoms (Baseline and 

Follow-up) and Treatment 

Adherence

(CMAssess= yes)*

Depression Care Manager (DCM) assesses depression 

symptoms with a structured instrument at baseline and at 

one or more follow-up visits; and also assesses treatment 

adherence (dichotomous)

Distribution adequate for short-term and intermediate-term 

but not for long-term, based on too few “no” category studies.

Active Self-Management 

Support

(self_manage = yes))

Facilitates active self-management (goal-setting and/or patient activation), provides patient education, and encourages 

adherence to plan and tracking of progress (dichotomous)

Distribution adequate for short-term, intermediate-term and 

long-term.

Care Manager Triage to Mental Health

(MH_spec=yes)

DCM guided patients to mental health specialty instead of 

primary care based on preferences, symptoms, co-morbidities, or other clinical judgment (dichotomous)

Distribution adequate for short-term, intermediate-term and 

long-term.

Primary Care Clinician Adjusts Antidepressants

(MedAdjR=yes)

Primary care clinician adjusted antidepressant medications 

with review and input as needed from a mental health specialist or other depression medication expert (dichotomous)

Distribution adequate for short-term and intermediate-term, 

but not for long-term, based on too few “no” category studies. 

Care Managers are Medical 

Nurses (CMMedNurse=yes)

Care managers were predominantly medical nurses rather 

than psychiatric nurses, other mental health professionals, 

pharmacists, or health educators (dichotomous)

Distribution adequate for short-term, intermediate-term and 

long-term.
30

Variable Name Variable Definition and Distribution†

Intensity of Intervention 

Assessment and Follow-Up 

(robustness=high, medium, 

or low)

Intensity is defined by three features: (1) DCM structured 

assessment of depression symptoms (baseline and followup) and treatment adherence, (2) adequate number ( mean 

of >3) of DCM contacts, and (3) antidepressant adjustment 

by the primary care clinician with expert guidance. The 

three levels of intensity are based on having one, two, or 

three features (categorical)

Distribution adequate for short-term, but not for intermediate-term or long-term based on too few “medium” category 

studies.

Classic Collaborative Care 

Intervention With Long 

Follow-up

(type_int1= yes)

Has care management by an RN or doctoral level pharmacist, primary care clinician collaboration with mental health 

specialty, patient education, and follow-up for at least 16 

weeks (either by telephone or in person) (dichotomous) 

Distribution adequate for short-term, intermediate-term and 

long-term.

Active Patient Follow-up for 

At Least 16 Weeks

(_16_weeks = yes)

Intervention included at least 16 weeks of active patient 

follow-up (dichotomous) 

Distribution adequate for short-term, but not for intermediate-term or long-term based on too few “no” category studies. 

Overall Intervention Impact

(impact = high (1), medium 

(2), low (3), little or no (4))

Independent judgment regarding how certain and how large 

the impact of the intervention was by two reviewers blinded 

to study methods or results (viewing extracted study outcomes only). 

Raters identified four levels of impact (high, medium, low, 

and little or no impact). Judgments were based on effect 

size/significance of intervention impact on depression 

symptoms, process of care, patient satisfaction, and overall 

quality of life, considering all time points.

(categorical)

Distribution adequate for short-term, but not for intermediate-term or long-term. This is based on too few “3” 

category studies for medium-term and too few “ 2” & “3” 

categories for long-term.
31

Variable Name Variable Definition and Distribution†

Type of Self-Management 

Support

[A = Active (use of behaviorally-oriented techniques), P = 

Passive (educational materials without personal contact), 

N = No evidence of self-management support)

Intervention included self-management support or there 

was no evidence of self-management support. Support was 

either active or passive. Used only for qualitative analysis 

(categorical).

Primary Care Clinicians Are 

Involved

(PCP_Involve = yes)

The intervention specified that primary care clinicians be 

actively involved in decision-making on depression management, rather than delegating decision-making to others after 

initial referral to collaborative care (dichotomous). 

Distribution not adequate for short-term, intermediateterm or long-term based on too few “no” category studies. 

Mental Health Specialists are 

Involved

(MH_Specialty = yes)

The intervention specified that one or more mental health 

specialists be actively involved in monitoring patients, either 

directly or through communication with the primary care 

clinician or care manager, after initial referral to collaborative care. (dichotomous).

Distribution not adequate for short-term, intermediateterm or long-term based on too few “no” category studies.

Standardized Care Manager 

Baseline Symptom Assessment 

(CM_Staff_Base_Sx = yes)**

Dedicated care manager staff conducted assessment of 

patient symptoms at baseline using a standardized scale. By 

dedicated, we mean an individual who carried out this function as a defined, discrete job, rather than e.g. a primary care 

clinician or pharmacist engaged in usual practice. Usually 

studies also indicated specific training (dichotomous). 

Distribution not adequate for short-term, intermediateterm or long-term based on too few “no” category studies. 
32

Variable Name Variable Definition and Distribution†

Standardized Care Manager 

Follow-up Symptom Assessment

(CM_Staff_F_U_SX = 

yes)***

Dedicated care manager staff conducted followed up assessments of patient symptoms using a standardized scale. By 

dedicated, we mean an individual carried out this function as 

a defined, discrete job. Usually studies also indicated specific training (dichotomous). 

Distribution adequate for short-term, but not mediumterm or long-term based on too few “no” category studies. 

Care Manager Follow-up of 

Treatment Adherence 

(CM_Staff_F_U_Adh = 

yes)****

Dedicated care manager staff F\followed patients proactively for treatment adherence. By dedicated, we mean an 

individual who carried out this function as a defined, discrete job. Usually studies also indicated specific training 

(dichotomous). 

Distribution not adequate for short-term, intermediateterm or long-term based on too few “no” category studies.

*CMAssess2 same as CMAssess except that the Dietrick article is coded as “yes” rather than “9” for base symtoms

**Same coding as BaseSx except that the Dietrick article is coded as “yes” rather than “9”

***Same coding as DepScale

****Same coding as TxAdhere

†Adequacy of variable distribution is based on having at least three studies with each variable value, see analysis 

methods. Short-term, medium-term, and long-term refer to time of measurement of effects, see outcome variable 

definitions. Intervention characteristics that were too prevalent in the sample to be investigated quantitatively and 

were therefore subjected to qualitative impact analysis are listed in bold.
33

Table 2: Summary of study design characteristics

Characteristic Category n 

Study quality Low risk of bias 18 

Moderate risk of bias 6 

High risk of bias 4 

Comparator Usual care 15 

Usual care: all patients 12 

starting antidepressant 

Consult-liaison 1 

mental health 

Location Latin America 1 

United States 23 

Western Europe 4 

Setting Community 8 

Academic 2 

HMO or Veterans Affairs 15 

Mixed 3 

Patient recruitment Systematic screening 11 

Administrative database 6 

or pharmacist 

Clinician referral 9 

Mixed 2 

Major depression < 75% of patients 14 

had MDD 

>= 75% of patients 9 

had MDD 

Unknown 5 

Patient population < 25% ethnic minorities 15 

>= 25% ethnic minorities 7 

Unknown 6 

Psychiatric comorbidity Not excluded systematically 13 

Bipolar disorder, psychosis 15 

and substance abuse 

excluded or triaged to 

mental health specialist 
34 45

Design Features Versus Study Effects on Depression Symptoms or Depression Resolution* 

Depression Symptom Effects 

Depression 

Resolution 

Response 

Category n

Short-term 

Effect Size 

(95% CI) n

Medium-term 

Effect Size 

(95% CI) n

Long-term

Effect Size 

(95% CI) n

Relative 

Risk

(95% CI) 

Few 5 

-0.18 

(-0.43, 0.06) 5 

-0.08 

(-0.38, 0.22) 2 

-0.02 

(-0.40, 0.35) 5 

1.19 

(0.90, 1.55) 

Medium 8 

-0.33 

(-0.50, -0.17) 8

-0.32 

(-0.52, -0.12) 4

-0.12 

(-0.34, 0.11) 8

1.49 

(1.20, 1.84) 

he 

Many 8 

-0.28 

(-0.46, -0.11) 5 

-0.26 

(-0.50, -0.01) 4 

-0.33 

(-0.54, -0.12) 5 

1.47 

(1.15, 1.88) 

Yes 7 

-0.37 

(-0.53, -0.20) 8

-0.33 

(-0.52, -0.13) 7

-0.24 

(-0.41, -0.07) 6

1.76 

(1.44, 2.14) 

er 

No 14 -0.23 (-0.36, -0.10) 10 -0.18 (-0.37, 0.01) 3 -0.07 (-0.36, 0.22) 12 1.24 (1.08, 1.43)* 

Yes 7 

-0.23 

(-0.42, -0.03) 8

-0.14 

(-0.35, 0.08) 2

-0.08 

(-0.46, 0.30) 8

1.24 

(1.02, 1.52) 

and 

o 

No 14 

-0.31 

(-0.44, -0.19) 10 

-0.32 

(-0.49, -0.15) 8 

-0.22 

(-0.38, -0.05) 10 

1.53 

(1.28, 1.82) 

Yes 13 

-0.30 

(-0.44, -0.16) 12 

-0.27 

(-0.44, -0.09) 3 

-0.10 

(-0.40, 0.19) 11 

1.32 

(1.11, 1.58) 

No 8 

-0.27 

(-0.43, -0.10) 6 

-0.22 

(-0.45, 0.00) 7 

-0.23 

(-0.41, -0.06) 7 

1.53 

(1.22, 1.90) 

Yes 6 

-0.35 

(-0.55, -0.14) 7 

-0.29 

(-0.51, -0.06) 4 

-0.16 

(-0.39, 0.07) 6 

1.50 

ts (1.17, 1.93) 

No 10 

-0.24 

(-0.41, -0.08) 8 

-0.24 

(-0.46, -0.02) 6 

-0.23 

(-0.42, -0.03) 12 

1.35 

(1.14,1.61) 

riable descriptions.
35 46

tive Care Intervention Model Feature Effects on Depression Symptoms or Depression Resolution 

Depression Symptom Effects 

Depression 

Resolution 

Response 

Category n

Short-term 

Effect Size 

(95% CI) n

Medium-term 

Effect Size 

(95% CI) n

Long-term:

Effect Size 

(95% CI) n

Relative Risk 

(95% CI) 

Yes

15 -0.23 (-0.34, -0.12) 15 -0.20 (-0.33, -0.06) 10 NE 14 1.38 (1.17, 1.62) 

on 

d 

nt 

No

6 -0.44 (-0.63, -0.25) 3 -0.53 (-0.83, -0.22) 0 NE 4 1.47 (1.09, 1.98) 

Yes 7 -0.37 (-0.54, -0.20) 8 -0.33 (-0.53, -0.13) 4 -0.30 (-0.51, -0.08) 8 1.64 

t (1.36, 1.99)* 

No 14 -0.24 (-0.37, -0.11) 10 -0.18 (-0.37, 0.00) 6 -0.12 (-0.31, 0.07) 10 1.24 (1.04, 1.46) 

Yes

7 -0.20 (-0.38, -0.02) 6 -0.14 (-0.38, 0.10) 4 -0.02 (-0.25, 0.20) 5 1.29 (0.98, 1.69) 

No

14 -0.33 (-0.45, -0.20) 12 -0.30 (-0.46, -0.14) 6 -0.29 (-0.45, -0.14) 13 1.44 (1.22, 1.70) 

Yes 17 -0.25 (-0.36, -0.13) 14 -0.19 (-0.34, -0.04) 8 -0.18 (-0.35, -0.01) 15 1.34 

(1.15, 1.56) 

 

No 4 -0.44 (-0.66, -0.21) 4 -0.45 (-0.72, -0.19) 2 -0.25 (-0.59, 0.09) 3 1.69 (1.23, 2.33) 

Yes 8 -0.31 (-0.48, -0.15) 9 -0.31 (-0.50, -0.13) 6 -0.28 (-0.45, -0.11) 7 1.60 (1.32, 1.94) 

d 

s 

No 13 -0.26 (-0.40, -0.12) 9 -0.17 (-0.37, 0.03) 4 -0.05 (-0.28, 0.18) 11 1.26 (1.07, 1.49) 
36 47

ive Care Intervention Model Feature Effects on Depression Symptoms or Depression Resolution 

)* 

Depression Symptom Effects Depression Resolution 

Response 

Category 

n

Short-term 

Effect Size 

(95% CI) 

n

Medium-term 

Effect Size 

(95% CI) 

n

Long-term

Effect Size 

(95% CI) 

n

Relative Risk 

(95% CI) 

High 11 -0.21 (-0.36, -0.07) 11 -0.19 (-0.36, -0.01) 6 -0.20 (-0.41, 0.01) 11 1.37 (1.13, 1.65) 

Med 4 -0.28 (-0.52, -0.05) 2 -0.17 (-0.55, 0.21) 1 -0.08 (-0.58, 0.41) 2 1.33 (0.89, 1.98) 

Up 

Low 6 -0.40 (-0.59, -0.22) 5 -0.42 (-0.67, -0.16) 3 -0.23 (-0.52, 0.07) 5 1.50 (1.14, 1.96) 

Yes 14 

-0.29 

(-0.42, -0.16) 13 

-0.24 

(-0.40, -0.07) 5 

-0.34 

(-0.50,-0.17)* 13 

1.44 

(1.22, 1.70) 

re 

 

No 7 

-0.27 

(-0.46, -0.08) 5

-0.28 

(-0.55, -0.02) 5

-0.05 

(-0.23, 0.13) 5

1.28 

(0.98, 1.68) 

Yes 17 

-0.24 

(-0.34, -0.13)* 16

-0.20 

(-0.33, -0.07)* 8

-0.22 

(-0.39, -0.06) 16

1.38 

(1.19, 1.60) 

 

No 4 

-0.52 

(-0.75, -0.28) 2 

-0.63 

(-1.00, -0.26) 2 

-0.08 

(-0.42, 0.26) 2 

1.59 

(1.04, 2.43) 

iable descriptions.
37

48

p between Qualitative Impact Variable and Effects on Depression Symptoms and Resolution* 

Depression Symptoms 

Depression 

Resolution 

Response 

Category n

Short-term: 

Effect Size 

(95% CI) n

Intermediate: 

Effect Size 

(95% CI) n

Long-term:

Effect Size 

(95% CI) n

Relative Risk 

(95% CI) 

High Impact 

(1) 8

-0.40 

(-0.56, -0.24) 9

-0.42 

(-0.59, -0.25) 4

-0.37 

(-0.56, -0.18) 8

1.71 

(1.47, 1.99) 

Medium 

(2) 6 

-0.26 

(-0.44, -0.08) 4 

-0.15 

(-0.39, 0.08) 1 

-0.08 

(-0.47, 0.31) 5 

1.35 

(1.12, 1.63) 

Low

(3) 3

-0.30 

(-0.59, -0.01) 1

-0.11 

(-0.58, 0.36) 2

-0.10 

(-0.39, 0.18) 2

1.24 

(0.88, 1.76) 

act 

Little or no 

impact 

(4) 4 

-0.07 

(-0.30, 0.16)* 4

0.02 

(-0.25, 0.29)* 3

-0.01 

(-0.28, 0.25)* 3

0.91 

(0.70, 1.18)* 

r full description of the impact variable.
38 49

ct Analysis Table of Intervention Features*

Self

ment 

rt 

Primary Care 

Clinicians

Actively

Involved in 

Patient

Management 

(PCP_Involve) 

Mental Health 

Specialists

Actively

Involved in 

Patient

Management 

(MH_Specialty) 

CM Baseline 

Assessment of 

Patient

Symptoms with 

Standardized 

Scale

(CM_Staff_ 

Base_Sx)

CM Follow-up 

Assessment of Symptoms with 

Standardized 

Scale

(CM_Stff_ 

F_U_Sx)

CM Follow-up 

Assessment of 

Treatment 

Adherence 

(CM_Stff_ 

F_U_Adh) 

Intervention 

included at least 

16 weeks of active 

patient follow-up 

(_16_weeks) 

Overall

Impact 

(impact) 

 (use 

rally

d

es)

ive 

onal

ls

sonal 

t)

dence 



ment

rt

Y= Yes 

N= No 

Y= Yes 

N= No 

Y= Yes 

N= No 

Y= Yes 

N= No 

Y= Yes 

N= No 

Y= Yes 

N= No

1= High 

2 = Medium 

3 = Low 

4 = Little or 

None

Y Y Y Y Y N 1Y Y Y Y Y Y 1Y Y Y Y Y Y 1Y Y N Y Y Y 1Y Y Y Y Y Y 1Y Y Y Y Y Y 1Y Y Y Y Y Y 1Y Y Y Y Y Y 1Y Y Y N Y Y 1Y Y Y Y Y Y 2Y Y Y Y Y Y 2Y Y N N Y Y 2
39 50

elf

ment 

rt 

Primary Care 

Clinicians

Actively

Involved in 

Patient

Management 

(PCP_Involve) 

Mental Health 

Specialists

Actively

Involved in 

Patient

Management 

(MH_Specialty) 

CM Baseline 

Assessment of 

Patient

Symptoms with 

Standardized 

Scale

(CM_Staff_ 

Base_Sx)

CM Follow-up 

Assessment of Symptoms with 

Standardized 

Scale

(CM_Stff_ 

F_U_Sx)

CM Follow-up 

Assessment of 

Treatment 

Adherence 

(CM_Stff_ 

F_U_Adh) 

Intervention 

included at least 

16 weeks of active 

patient follow-up 

(_16_weeks) 

Overall

Impact 

(impact) 

 (use 

rally

d

es)

ve 

nal

s

sonal 

)

ence 

ent

t

Y= Yes 

N= No 

Y= Yes 

N= No 

Y= Yes 

N= No 

Y= Yes 

N= No 

Y= Yes 

N= No 

Y= Yes 

N= No

1= High 

2 = Medium 

3 = Low 

4 = Little or 

None

Y Y Y Y Y Y 2Y Y Y N N N 2Y N Y Y Y Y 2Y Y Y Y Y Y 2Y Y Y Y Y Y 3Y Y Y Y Y Y 3Y Y Y Y Y Y 3

N ? Y Y Y N 3

 Y = 19 Y = ?18 Y = 18 Y = 17 Y = 19 Y = 17 

Y Y Y Y Y Y 4
40 51

Self

ment 

rt 

Primary Care 

Clinicians

Actively

Involved in 

Patient

Management 

(PCP_Involve) 

Mental Health 

Specialists

Actively

Involved in 

Patient

Management 

(MH_Specialty) 

CM Baseline 

Assessment of 

Patient

Symptoms with 

Standardized 

Scale

(CM_Staff_ 

Base_Sx)

CM Follow-up 

Assessment of Symptoms with 

Standardized 

Scale

(CM_Stff_ 

F_U_Sx)

CM Follow-up 

Assessment of 

Treatment 

Adherence 

(CM_Stff_ 

F_U_Adh) 

Intervention 

included at least 

16 weeks of active 

patient follow-up 

(_16_weeks) 

Overall

Impact 

(impact) 

 (use 

rally

d

es)

ive 

nal

ls

sonal 

t)

dence 



ment

t

Y= Yes 

N= No 

Y= Yes 

N= No 

Y= Yes 

N= No 

Y= Yes 

N= No 

Y= Yes 

N= No 

Y= Yes 

N= No

1= High 

2 = Medium 

3 = Low 

4 = Little or 

None

N N N Y Y N 4

Y Y Y Y Y Y 4Y Y Y Y Y N 4Y Y Y Y Y Y 4Y N Y N Y Y 4

N N N N Y N 4

Y Y Y Y Y N 4

 Y = 6 Y = 5 Y = 6 Y = 6 Y = 8 Y = 4 

 full description of the impact variable. See Table 1 for full descriptions of the remaining variables. **VA studies. ***Had a VA site. 
41 53

omorbidity Ranked by Overall Impact* 

n with 

ressive 

der 

D)

proportion 

non-white 

(Minority) 

exclude

substance 

abuse? 

(e_sa) 

exclude

dementia? 

(E_Dementia) 

exclude ptsd? 

(E_PTSD)

exclude

anxiety? 

(E_Anxiety) 

exclude

psychosis? 

(E_Psychosis)

exclude

bipolar

disorder? 

(E_BD)

overall 

impact 

1= yes 

0= No 

1= yes 

0= No 

1= yes 

0= No 

1= yes 

0= No 

1= yes 

0= No 

1= yes 

0= No 

1= High 

2 = Medium 

3 = Low 

4 = Little or 

None

1 1 0 0 0 1 1 1

9 No Data 1 1 9 0 1 1 1

24 0.13 1 1 9 0 1 1 198 0.17 1 9 9 0 1 1 1

2 0.25 1 0 0 0 1 1 1

0.17 1 9 0 0 1 1 1

9 0.2 0 0 0 0 1 1 1

63 0.43 0 1 0 0 0 0 1

9 0.245 1 1 0 0 1 1 1

62 0.33 0 1 0 0 0 0 2

9 0.167 1 0 1 0 1 1 2

0.37 1 0 0 0 1 1 2

88 0.55 0 1 1 0 1 1 2

9 No Data 0 1 0 0 1 0 2

74 0.157 1 9 9 9 0 1 2

No Data 1 1 0 0 1 1 2

47 0.2 1 9 9 9 1 1 3

2 0.253 1 1 0 0 1 1 3

44 0.2 1 1 1 0 1 1 3

4 No Data No Data 0 0 0 0 No Data 36 0.276 1 1 0 0 1 1 4

0.01 0 0 0 0 0 0 4

1 0.22 1 0 0 0 1 0 49 0.05 0 1 0 0 1 1 4

No Data 1 0 0 0 1 1 4

2 No Data 0 0 0 0 0 1 4

0.08 0 0 0 0 1 1 4

8 0.142 1 1 9 9 1 1 4

full description of the impact variable. See Table 1 for full descriptions of the remaining variables.
4253

ures ranked by overall impact* 

verall impact (impact) number of practices (practice group) type of randomization type of referral 

1= High 

2 = Medium 

3 = Low 

 = Little or None

Small = 1 to 2 

Medium = 3 to 10 

Large >10 

1 = Patient Level 

2 = Practice Level 

3 = Provider Level 

1 = Referred by PCP and on medications or 

willing to take medications 

2 = Referred by PCP or screened and referred 

3 = On medications 

4 = Screened 

1 M 1 41 S 1 11 S 1 11 M 1 11 M 1 11 L 3 41 M 1 31 L 2 41 community 1 42 L 2 42 L 2 12 S 1 12 M 3 42 L 1 32 L 2 42 M 1 33 L 2 23 M 2 43 M 2 23 L 1 24 M 1 44 community 1 34 S 1 14 M 3 44 S 1 14 L 1 24 Community 1 34 S 2 4

r full description of the impact variable. See Table 1 for full descriptions of the remaining variables.
43

56

ng Self-Management Support 

Type of SelfManagement Support Type of Patient Intervention 

A = Active (use of 

behaviorally-oriented 

techniques)

P = Passive (educational 

materials without personal 

contact)

N = No evidence of selfmanagement support 

A

Modality: Psychoeducational intervention group Delivered by: Social workers and nurses Content: Depression assessment 

Treatment options 

Theory: Problem-solving techniques 

Scheduling positive activities Basic cognitive and relapse-prevention techniques 

Quantity: 7 weekly sessions and 2 booster sessions Others Involved: Structured pharmacotherapy program with PCP if severe depression after 6 weeks Materials: Manual with examples and exercises 

A

Modality: Psychiatry visits Delivered by: Psychiatrist Content: Depression assessment 

Understanding antidepressant action and side effects Review of stressful life events 

Theory: No formal psychotherapy Quantity: 2 to 4 visits with psychiatrist Others Involved: PCP visits alternated with psychiatrist visits Materials: Booklet on biology of depression and how antidepressants work 

Booklet on simple cognitive-behavioral techniques for managing depression Video with doctor-patient vignettes Questionnaire to motivate active patient role 
44 57

Type of SelfManagement Support Type of Patient Intervention 

A = Active (use of 

behaviorally-oriented 

techniques)

P = Passive (educational 

materials without personal 

contact)

N = No evidence of selfmanagement support 

A

Modality: PsychotherapyDelivered by: Psychologist Content: Depression assessment 

Antidepressant assessment 

Theory: Therapeutic techniques based on social cognitive theory and social learning theory 

 models Sessions 1-4: education, skills training, homework assignments or behavioral  experiments to improve mood and facilitate generalization of skills to daily life Sessions 5-6 (optional): skills training in assertion, problem-solving communications  in conflictual situations, and relaxation training 

Quantity: 4 to 6 direct contacts followed by 4 telephone contacts Others Involved: Optional referral to psychiatrist for nonresponding patients Materials: Booklet on biology of depression and how antidepressants work 

Booklet on simple cognitive-behavioral techniques for managing depression; “I can If I Want To”Video with doctor-patient vignettes 

A

Modality: Psychiatry visits Delivered by: Psychiatrist Content: Depression assessment 

Review of stressful life events Review of medication adherence and side effects Review of medical, family, and social history 

Theory: Optional psychotherapy for patients with severe psychosocial stressors Quantity: 2 sessions with psychiatrist with additional visits based on clinical response—brief telephone 

call between visits 

Others Involved: PCP encouraged to discuss patient reactions/questions regarding educational materials 
45 58

Type of SelfManagement Support Type of Patient Intervention 

A = Active (use of 

behaviorally-oriented 

techniques)

P = Passive (educational 

materials without personal 

contact)

N = No evidence of selfmanagement support 

Materials: Book and videotape addressing biology of depression, antidpressdant medications, 

psychotherapy, and active self-management 

A

Modality: Pathways case management intervention—antidepressant medications and/or PST-PC Delivered by: Depression Clinical Specialist Nurse Content: Enhanced education 

Support for antidepressant medication 

Theory: Problem-solving treatment in primary care (PST-PC) Quantity: Initial visit, step 1—twice montly contacts for 10-12 weeks, step2—bimonthly contacts for 8-

12 weeks, step 3—referral to mental health system for longer–term follow-up if needed, continuation phase—monthly contacts or groups if significant decrease in symptoms 

Others Involved: Optional psychiatric consultation, collaboration with PCP Materials: None specified 

P

Modality: Telephone-based treatment coordination Delivered by: Treatment coordinators some with mental health background Content: Depression assessment 

Treatment adherence and medication effects 

Theory: No formal psychotherapy Quantity: PCP visits: initial, follow-up at 1, 3, 6, 10 weeks, then every 10 weeks; treatment coordinator 
46 59

Type of SelfManagement Support Type of Patient Intervention 

A = Active (use of 

behaviorally-oriented 

techniques)

P = Passive (educational 

materials without personal 

contact)

N = No evidence of selfmanagement support 

contacts: at 2, 10 weeks, and if needed at 18, 30, 42 weeks 

Others Involved: PCP, Psychiatric consultation encourage if no response to treatment at 10 weeks or if 

complicated depression 

Materials: Booklet on “Depression isn’t Just a Mental Problem,” video, RHYTHMS depression education 

program if appropriate to support antidepressant use 

A

Modality: Psychotherapy (telephone-based) Delivered by: Psychotherapists Content: Depression assessment 

Antidepressant use and adverse effects 

Theory: CBT program Quantity: CBT: 1—motivation, 2 to 4—increasing pleasant and rewarding activities, 5-7—identifying 

challenges and distancing from negative thoughts, 8—self-care plan 

Others Involved: Care managers: mental health clinicians with bachelor’s or master’s degrees (care 

management program in addition to psychotherapy) 

Materials: Detailed care management workbook emphasizing activation, addressing negative thought, 

developing self- care plan 

A

Modality: IMPACT intervention—antidepressant medications and/or PST-PC Delivered by: Nurses or psychologists trained as depression care managers Content: Depression assessment Theory: Problem-solving treatment in primary care (PST-PC) Quantity: PST-PC: 6-8 sessions; care manager contacts every other week during the acute phase and 

monthly if reduction in symptoms up to 12 months 

Others Involved: Psychiatrist contact if lack of response or diagnostic challenge; PCP Materials: Video, booklet 
47 60

Type of SelfManagement Support Type of Patient Intervention 

A = Active (use of 

behaviorally-oriented 

techniques)

P = Passive (educational 

materials without personal 

contact)

N = No evidence of selfmanagement support 

A

Modality: Psychotherapy or antidepressant medication support Delivered by: QI meds: Nurse specialists 

QI therapy: Psychotherapists 

Content: QI meds: depression assessment, support adherence 

QI therapy: individual and group CBT 

Theory: CBTQuantity: Initial visit for assessment, education, and activation 

QI meds: monthly contacts QI therapy: 12 to 16 sessions 

Others Involved: Not specified Materials: Videos and pamphlets 

A

Modality: Treatment management Delivered by: Depression care managers Content: Depression assessment 

Treatment adherence and medication adverse side effects PCP could recommend interpersonal psychotherapy if patient declined medication 

Theory: Not specified Quantity: At scheduled intervals or when clinically necessary—frequency not specified Others Involved: Collaborated with PCP Materials: Not specified 

A

Modality: Telephone-based care management Delivered by: Care managers—most with backgrounds in primary care or mental health nursing Content: Overcoming barriers to adherence 

Supported self-management practices (e.g., exercise, social activities) 

Theory: Not specified 
48 60

Type of SelfManagement Support Type of Patient Intervention 

A = Active (use of 

behaviorally-oriented 

techniques)

P = Passive (educational 

materials without personal 

contact)

N = No evidence of selfmanagement support 

Quantity: Initial contact, contacts monthly thereafter or as needed Others Involved: Intervention clinician Materials: Not specified 

A

Modality: Telehealth careDelivered by: Primary care nurses Content: Antidepressant adherence, side effects, questions 

Emotional support to find pleasurable activities and to be more active Support for behavior plan 

Theory: Not specified Quantity: Weeks 1-2: 1 to 2 calls per week; weeks 3-8: 1 call per week; weeks 9-16: 1 call every other 

week

Others Involved: Peer support in addition to nurse telehealth care in 35% of intervention patients Materials: Not specified 

A

Modality: Telephone disease management Delivered by: Behanioral health specialist (nurses with behavioral health experience) Content: Depression assessment 

Treatment adherence and adverse effects Education and motivation support 

Theory: Not specified Quantity: Calls at 1, 3, 6, 9, 12, 18, and 24 weeks after initial assessment Others Involved: PCPMaterials: Not specified for depression; workbook for alcohol intervention 

P

Modality: Drug counseling Delivered by: Primary care nurses Content: Education—depression, self-help, treatment adherence 
49 61

Type of SelfManagement Support Type of Patient Intervention 

A = Active (use of 

behaviorally-oriented 

techniques)

P = Passive (educational 

materials without personal 

contact)

N = No evidence of selfmanagement support 

Theory: No formal psychotherapy Quantity: At weeks 2 and 8 Others Involved: Not specified Materials: Information leaflet 

A

Modality: Pharmacotherapy and/or psychotherapy Delivered by: NursesContent: Depression assessment 

Education about treatments Supported activation/engagement 

Theory: Not specifed Quantity: Average of 5.2 contacts during the first 8 weeks after index visit Others Involved: PCP, access to specialty care psychotherapy Materials: AHCPR pamphlet 

N

Modality: Care management (1 of 2 interventions) Delivered by: Care managers Content: Antidpressant use, side effects 

Depression assessment General support 

Theory: No specific psychotherapeutic content Quantity: Brief initial call followed by 2 calls at 8 and 16 weeks Others Involved: PCPMaterials: Not specified 

N

Modality: Telephone disease management Delivered by: Nurses
50 62

Type of SelfManagement Support Type of Patient Intervention 

A = Active (use of 

behaviorally-oriented 

techniques)

P = Passive (educational 

materials without personal 

contact)

N = No evidence of selfmanagement support 

Content: Education topics: depression, treatment options,coping skills, risk factors,suicide prevention, 

reinforcing followup Depression assessment Treatment adherence 

Theory: Not specified Quantity: Followup contact at least every 3 weeks; formal assessment at baseline, 6, 12, and 16 weeks Others Involved: PCPMaterials: Not specified 

A

Modality: Telemedicine-based collaborative care (stepped care) Delivered by: NursesContent: Education’

Activation and barrier assessment/resolution activities Depression assessment Treatment adherence and side effects 

Theory: Psychotherapy was available but not facilitated Quantity: Followup: acute—every 2 weeks, watchful waiting or continuation—every 4 weeks for up to 

12 months 

Others Involved: PCP, pharmacist Materials: Pamphlet and website 
51 63

Type of SelfManagement Support Type of Patient Intervention 

A = Active (use of 

behaviorally-oriented 

techniques)

P = Passive (educational 

materials without personal 

contact)

N = No evidence of selfmanagement support 

P

Modality: Collaborative care (treatment options: antidepressant medication initiation or adjustment, 

CBT, scheduling with psychologist or psychiatrist, mental health specialty care) 

Delivered by: CBT: Psychologist or social worker Content: Encourage adherence 

Address treatment barriers Depression assessment 

Theory: CBTQuantity: CBT: 6 sessions Others Involved: Team: clinical psychologist, psychiatrist, social workers, psychology technician Materials: Video and workbook 

A

Modality: Multifaceted package of care Delivered by: Community psychiatric nurse (CPN) Content: Depression assessment 

EducationPsychological interventions: 94% of intervention patients Pharmacotherapy: 66% of intervention patients 

Theory: Personal supportive therapy, behaviour therapy and relaxation, family and marital work, 

bereavement counseling 

Quantity: Weekly visits over 3 months and contact phone number Others Involved: GPMaterials: Not specified 

P

Modality: Antidepressant medication support Delivered by: Pharmacist Content: Medication adherence 

General social support 
52

64

Type of Self

agement Support Type of Patient Intervention 

= Active (use of 

aviorally-oriented 

techniques)

assive (educational 

als without personal 

contact)

o evidence of self

agement support 

Theory: No formal psychotherapy Quantity: Contacts at 2,4,6,8 weeks and 6,9,12,18 months Others Involved: Not specified Materials: Not specified 

P

Modality: Antidepressant medication support Delivered by: Pharmacist Content: “a list of important themes” not specified Theory: No formal psychotherapy Quantity: 3 coaching contacts Others Involved: Not specified Materials: Video

N

Modality: Collaborative care Delivered by: Pharmacist Content: Depression assessment 

Antidpressant concerns addressed Support and education Antidpressant medication adjustments and side effects management Facilitation of mental health provider appointments 

Theory: No formal psychotherapy Quantity: Weeks 1-4—weekly calls, weeks 5-12—calls every 2 weeks, months 3-12—calls every other 

month

Others Involved: PCP , psychiatrist Materials: Not specified 

P

Modality: Decision support Delivered by: Depression decision support nurse care manager 
53 65

Type of SelfManagement Support Type of Patient Intervention 

A = Active (use of 

behaviorally-oriented 

techniques)

P = Passive (educational 

materials without personal 

contact)

N = No evidence of selfmanagement support 

Content: Education--explore barriers,treatment adherence, encourage communication with providers Theory: No formal psychotherapy Quantity: 1 early telephone contact Others Involved: Psychiatrist Materials: Supplemental educational materials 

N

Modality: Drug therapy management (feature of collaborative care) Delivered by: Pharmacist Content: Antidepressant adherence and adverse effects, titrate medications 

Depression assessment Other social and medical factors 

Theory: No formal psychotherapy Quantity: Calls at weeks 1,2,4,10, and 16, clinic visits at weeks 6 and 24 Others Involved: Not specified Materials: Not specified 

N

Modality: Monitoring (1 of 2 interventions) Delivered by: Practice nurses Content: Content of interview recorded as follows: monitoring change in mental health, encouraging 

compliance, providing education, facilitating social intervention 

Theory: No formal psychotherapy Quantity: 8 hours per patient over 4 months re commended Others Involved: GPMaterials: Not specified 

N

Modality: Telemonitoring of antidepressant use Delivered by: Pharmacist Content: Medication adherence and adverse effects 
54 66

Type of SelfManagement Support Type of Patient Intervention 

A = Active (use of 

behaviorally-oriented 

techniques)

P = Passive (educational 

materials without personal 

contact)

N = No evidence of selfmanagement support 

Patient concerns 

Theory: No formal psychotherapy Quantity: 3 monthly telephone calls Others Involved: Not specified Materials: Not specified 

N

Modality: MonitoringDelivered by: Mental health clinical nurse specialists Content: Depression assessment 

Review side effects Encourage compliance with antidepressants 

Theory: No formal psychotherapy Quantity: Contacts at 2 weeks, 1 month, and 2 months after initial contact Others Involved: PCP, referral to mental health clinic if patient unable to take antidepressant medication for 

CBT or more complex medication regimen 

Materials: Not specified 
62

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