Evidence-based Synthesis Program Department of Veterans Affairs

Health Services Research & Development Service Evidence-based Synthesis Program 

A Critical Review

of the Literature Regarding

Homelessness among Veterans

Department of Veterans Affairs

Health Services Research & Development Service

April 2011

Prepared for:

Department of Veterans Affairs

Veterans Health Administration

Health Services Research & Development Service

Washington, DC 20420

Prepared by:

Evidence-based Synthesis Program (ESP) Center

Portland VA Medical Center

Portland, OR

Devan Kansagara, MD, MCR, Director

Investigators:

(all authors contributed equally to this report): 

Howard Balshem, MS

Vivian Christensen, PhD

Anais Tuepker, PhD
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A Critical Review of the Literature

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EXECUTIVE SUMMARY

BACKGROUND

In 2009, President Obama and Secretary Shinseki committed to ending homelessness among 

Veterans. In support of that effort, the Federal Strategic Plan to Prevent and End Homelessness 

2010 developed by the United States Interagency Council on Homelessness (USICH) 

established as one of its goals to prevent and end homelessness among Veterans in five years. 

An understanding of the epidemiology of homelessness among Veterans and the methodological 

strengths and weaknesses of this evidence base may inform program-planning efforts and future 

research needs. Understanding the risk factors for homelessness among Veterans and how these 

risk factors compare to the general population is important in developing identification and 

prevention programs for Veterans at risk for homelessness. This report was requested by VA 

Central Office and The National Center for Homelessness Among Veterans as part of that effort 

to identify what is known and what is not known about the prevalence of homelessness among 

Veterans, and about the risk factors for homelessness among Veterans, including risk factors 

related to military service and incarceration.

The key questions were:

Key Questions #1a. What is the prevalence and incidence of homelessness among Veterans?

#1b. How has the prevalence and incidence of homelessness among Veterans 

changed over time?

#1c. How prevalent are psychiatric illness, substance abuse, and chronic 

medical illness among homeless Veterans?

Key Questions #2a. Which risk factors are associated with new homelessness or a return to 

homelessness among Veterans? How do these risk factors differ from nonVeteran populations?

#2b. Have risk factors for homelessness among Veterans changed over time?

Key Question #3. Are there factors specific to military service that increase the risk 

of homelessness, or is the increased risk a marker for pre-military 

comorbidities and social support deficiencies?

Key Question #4. What is the relationship between incarceration and homelessness among 

Veterans?

METHODS

Key questions were developed with the input of experts from the National Center for 

Homelessness Among Veterans and the VA New England Healthcare System, and with 

feedback from national experts on homelessness and homelessness among Veterans. A search 

for relevant literature was conducted in MEDLINE, the Cochrane Database of Systematic 

Reviews, Sociological Abstracts, and Criminal Justice Abstracts from database inception through 
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July 2010. We also monitored Table of Contents alerts for several publications to identify 

new research published in 2010; searched several non-medical qualitative journals including 

Qualitative Research and Qualitative Health Research; and sought guidance on other sources 

from a survey of technical experts. For all Key Questions, the reference lists of articles returned 

were reviewed for any additional relevant studies. Because of the exploratory nature of this 

review, few restrictions were placed on articles to be considered for inclusion.

DATA SYNTHESIS

The existing evidence base relevant to this topic does not lend itself to a quantitative synthesis, 

since sample populations and variables investigated were rarely consistent across studies. In 

this report, we did not conduct a quantitative data synthesis or meta-analysis, but rather focused 

on presenting the strength of each existing study’s findings and developing a conceptual model 

for understanding what these findings mean collectively, as well as indicating where there are 

significant gaps in our knowledge on this topic.

PEER REVIEW

A draft version of this report was reviewed by six technical experts. Reviewer comments were 

addressed and our responses were incorporated in the final report (Appendix A).

RESULTS

KEY QUESTION #1A. What is the prevalence and incidence of homelessness among 

Veterans?

The recently released report Veteran Homelessness: A Supplemental Report to the 2009 Annual 

Homeless Assessment Report to Congress (2009 Veteran AHAR) estimates that on a single night 

in January 2009 there were 75,609 homeless Veterans and that an estimated 136,334 Veterans 

spent at least one night in an emergency shelter or transitional housing program between October 

1, 2008 and September 30, 2009. With nearly 23 million Veterans in the U.S. population in 2009, 

the prevalence of Veterans experiencing homelessness on a single night in January 2009 was 

approximately 33 for every 10,000 Veterans. Approximately 60 out of every 10,000 Veterans 

spent at least one night in an emergency shelter or transitional housing between October 1, 2008 

and September 30, 2009.

KEY QUESTION #1B. How has the prevalence and incidence of homelessness among 

Veterans changed over time?

Because of changes in reporting and in the methods for counting the number of homeless, 

estimates of the prevalence of homelessness among Veterans over time are not comparable. 

With regard to the percentage of Veterans among the homeless, in 1996, the National Survey of 

Homeless Assistance Providers and Clients estimated that 23 percent of the homeless population 

were Veterans. More recently, the first four Annual Homeless Assessment Reports (AHARs) 

estimated that the percentage of Veterans among the homeless stayed relatively steady at about 

15 percent. The most recent AHAR reported a decrease to 16 percent of adults and 12 percent of 
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all homeless individuals. The demographic composition of the Veteran homeless population is 

changing. According to the CHALENG report, VA facilities have recently reported an increase of 

24 percent in homeless Veteran families seeking services. In addition, the percentage of homeless 

women Veterans is expected to increase as the percentage of female Veterans has increased 

dramatically in recent years.

KEY QUESTION #1C. How prevalent are psychiatric illness, substance abuse, and chronic 

medical illness among homeless Veterans?

There are few studies directly assessing the prevalence of psychiatric illness, substance abuse, 

or chronic illness in the general population of homeless Veterans. The 2009 Veteran AHAR 

estimates that approximately 53 percent of homeless Veterans have some kind of disability. This 

estimate is based on a definition of disability that includes substance abuse, mental illness, and 

physical disabilities. Estimates for specific disabilities are not provided. However, most other 

studies rely on already morbid populations seeking treatment for services and so cannot provide 

estimates of prevalence in the homeless population as a whole. Prevalence estimates from a 

limited evidence base vary. A study based on a convenience sample of homeless adults admitted 

to homeless shelters in Santa Clara County, California between November 1989 and March 

1990 found that 17 percent of Veterans had been admitted for overnight treatment of psychiatric 

problems; that 29 percent reported actual and 39 percent perceived alcohol abuse; and 22 percent 

reported illegal drug use. More recently, a survey of randomly selected homeless adults in 

Pittsburgh and Philadelphia found that 61.4 percent reported psychiatric problems, 79.5 percent 

reported alcohol or drug abuse or dependence, and 66.1 percent reported having at least one 

chronic medical condition.

KEY QUESTION #2A. Which risk factors are associated with new homelessness or a 

return to homelessness among Veterans? How do these risk factors differ from non-Veteran 

populations?

Risk factors most strongly and consistently associated with homelessness in both Veteran and 

non-Veteran populations include childhood risk factors such as inadequate care by the parents, 

experiencing foster care or group placement, and prolonged periods of running away from home. 

Low or unstable income, low social support and a history of incarceration appear to place both 

Veterans and non-Veterans at increased risk for homelessness.

The most important risk factors for homelessness do not differ substantially between Veteran and 

non-Veteran populations. There are notable differences in the prevalence of some characteristics 

often found to be protective: Veteran homeless tend to be older and better educated; to have had 

better, early family cohesion; and are more likely to be or have been married than non-Veteran 

homeless. The reasons for this lack of expected protection are not well understood. It may be 

that the differences between these populations are too small to influence outcomes significantly. 

Alternatively, there may be unique Veteran experiences associated with either service or postdeployment readjustment that actively undermine the protective mechanism associated with 

these factors in other populations.
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KEY QUESTION #2B. Have risk factors for homelessness among Veterans changed over time?

Evidence shows that over time, certain risk factors become more salient than others and affect 

different sub-populations. With the increasing number of women in the military, military 

sexual trauma (MST) has become an important and prevalent additional trauma-associated 

risk factor. The wars in Iraq and Afghanistan have led to an increase in the number of National 

Guard Veterans serving often repeated tours of duty in these conflicts. Since these Veterans 

are more likely to have families during and immediately after deployment, the importance of 

factors related to homelessness among families may increase. Economic and structural factors 

also strongly influence who is at risk. In good economic times, those most vulnerable because 

of personal risk factors will become homeless; as economic conditions worsen, an increasing 

number of those less vulnerable will also become homeless.

KEY QUESTION #3. Are there factors specific to military service that increase the risk of 

homelessness, or is the increased risk a marker for pre-military comorbidities and social 

support deficiencies?

Some studies have found that homeless Veterans have lower prevalence of some general population 

risk factors (such as family dysfunction) and higher prevalence of protective factors (such as higher 

educational levels). These findings suggest that pre-military risk factors or comorbidities do not 

account for the over-representation of Veterans among the nation’s homeless. Veterans appear to 

be at risk for homelessness for much the same reasons as other Americans. However, their unique 

experiences as Veterans may mean that the pathways through which they come to be exposed to or 

develop these risks may be qualitatively different. This is an area which warrants further research.

An example of the influence of unique Veteran experiences may be found in considering the 

existing evidence on the impact of combat exposure. Although associated with only a subset 

of Veterans and homeless Veterans, prolonged or intense combat exposure has been found to 

negatively impact mental health, employment, income and social support, thus indirectly but 

substantially increasing the risk of homelessness among those Veterans who have had intense 

combat exposure compared to those who have not. Given that non-Veterans in the United States 

are unlikely to experience intense combat exposure, their pathways to low social support or poor 

mental health can only partially inform our understanding of homelessness among Veterans.

Some behaviors which may place Veterans at increased risk of homelessness seem likely to 

emerge during military service or during the readjustment/post-deployment period. These include 

problem alcohol use, problem substance use and/or low social support. While exposure to these 

risk factors is not intrinsic to military service, evidence suggests that military culture and/or the 

inherently disruptive nature of military service tours increase the likelihood of negative outcomes 

for both substance use and social support. 

Though only examined to date by one small study, MST has been associated with increased risk 

of homelessness among female Veterans. Further research is needed.

KEY QUESTION #4. What is the relationship between incarceration and homelessness 

among Veterans?

After a steady rise in the number of Veterans in prison since 1985, the number, which peaked 

at about 153,100 in 2000, had declined by about 9 percent to 140,000 by 2004. Literature on 
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incarceration and homelessness makes apparent the demographic similarities between homeless 

and incarcerated populations – both are typically poor, uneducated, and minority populations 

with few job skills – and suggests a bi-directional association between homelessness and 

incarceration. Factors found to be associated with homelessness among the incarcerated include 

ineffective discharge planning, legal and regulatory restrictions, full sentencing laws, and 

financial instability.

LIMITATIONS OF THE EVIDENCE

Although there is consistent evidence associating specific risk factors such as substance abuse 

and mental illness with homelessness, there are significant limitations with the data in terms of 

how well risk factors were defined and prevalence measured. Association does not, on its own, 

indicate causality, and very few studies reviewed were designed to measure the direction of 

associations. Studies are limited by several factors, including: inclusion of morbid populations 

seen in clinical settings that may not be generalizable to the broader population of Veterans; 

use of varying and often inconsistent definitions of homelessness; use of measures of unproven 

validity; and limitations in study design.

FUTURE RESEARCH

This report identifies a number of gaps in the literature and makes key suggestions to define an 

agenda for future research on Veteran homelessness:

• Longitudinal studies with Operation Enduring Freedom (OEF)/Operation Iraqi Freedom 

(OIF) Veterans are needed to capture data on exposures occurring before homelessness 

occurs. Given the VA’s current policy of pro-active enrollment and engagement of this 

cohort, opportunities exist to conduct longitudinal studies that collect information on all of 

the risk factors identified in this report. This research should control for structural risk factors 

such as housing market costs and available assistance programs.

• Longitudinal studies with all new cohorts of enlisting military service members could better 

determine the pre-existing presence of risk factors such as low social support, alcohol or 

substance abuse problems before military service. Policies should be developed to facilitate 

the use of data from enlistment screenings in research.

• Qualitative studies employing longitudinal, ethnographic methods to investigate the distinct 

experiences of homeless Veterans will help researchers to understand what is unique 

about Veteran exposure to risk factors common to the general homeless population. This 

remains poorly understood at present but may have important implications for designing 

homelessness prevention programs that will be effective for Veterans.

• Current research suggests that risk for violent criminal behavior varies by service branch. 

Research to confirm these differences and how to identify individuals at risk for continued 

post-military violent criminal behavior may help target interventions to those most at risk for 

post-military incarceration.
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• Research on the post-deployment period is needed, with a particular focus on risk factors 

for loss of income and social support during this transition period, as well as rates of shortterm homelessness experienced during this period. These data could be collected as part 

of longitudinal studies looking for relationships between short-term and more chronic 

homelessness, a topic that has been the focus of past research.

• Further research on MST, its relationship to homelessness, and appropriate MST prevention 

and treatment programs is recommended.

• Research on Veterans Courts and other types of specialty courts should be conducted in order 

to determine how they can most effectively provide alternatives to incarceration for Veterans.

• Systems-perspective research on collaborations among Departments of Corrections, the VA, 

the Department of Housing and Urban Development (HUD), and local community health 

agencies could inform efforts to reduce the likelihood of homelessness upon re-entry from 

incarceration, including developing a better understanding of how to identify those most at 

risk for homelessness post-release.

• Most of the measures used to assess risk factors and personal characteristics of the homeless, 

including measures of substance abuse, mental health, and measures of social support, have 

been developed and normed on populations living in conditions very different from the 

homeless. The applicability of these measures to homeless populations is unknown. Research 

should be undertaken to assess the applicability of these measures, and to modify or develop 

new measures where warranted. Similarly, better defined research on the aspects of social 

support most relevant to improving Veterans’ post-deployment adjustment would contribute 

both to addressing Veteran homelessness and the literature’s broader understanding of the 

function of social support.

• Long-term studies repeatedly collecting both quantitative and qualitative data, though 

always relatively difficult and costly to conduct, would greatly improve our understanding 

of Veterans’ difficulties in re-engagement and re-integration over long periods of time after 

deployment, not just in the initial post-deployment year, which is more frequently studied.

• Studies that include both individual and structural risk factors should be conducted to assess 

both their independent and contingent effects.

• Research is needed to investigate the relationship between the unique Veteran experience of 

“family readjustment difficulties” in the post-deployment period and other, more generalized 

concepts such as social support, as well as the relationship between family readjustment 

difficulties and clinical diagnoses of mental illness.

• To our knowledge, the direct relationship between injury/disability and increased risk 

of homelessness has not been well studied in the Veteran population. There is a need for 

research designed to examine injury as a risk factor for homelessness, both directly and 

indirectly, and taking into account the complex effects of serious injury on both income and 

quality of life/well-being.
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ABBREVIATIONS TABLE

ACCESS Access to Community Care and Effective Service Supports

AFDC Aid to Families with Dependent Children

AHAR Annual Homeless Assessment Report

ASI Addiction Severity Index

CHALENG Community Homelessness Assessment, Local Education and Networking Group

CI Confidence interval

CMHS Center for Mental Health Services

CoC Continuum of Care

DCHV Domiciliary Care for Homeless Veterans

DRRI Deployment Risk and Resilience Inventory

DSM-IV Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition

ELI Extremely Low Income

ESP Evidence-based Synthesis Program

FMR Fair market rent

GAINS National GAINS Center: Gathering information; Assessing what works;

Interpreting/integrating the facts; Networking; Stimulating change

GAO Government Accounting Office

HCHV Health Care for Homeless Veterans

HCMI Homeless Chronically Mentally Ill Veterans Program

Health VIEWS Health of Vietnam Era Veteran Women’s Study

HEARTH Homeless Emergency and Rapid Transition to Housing

HMIS Homeless Management Information System

HR Hazard ratio

HSR&D Health Services Research and Development Service

HUD Department of Housing and Urban Development

MCS Millennium Cohort Study

MOS Medical Outcomes Study

MPSI Multi-Problem Screening Inventory

MST Military sexual trauma

N or n Number

NSHAPC National Survey of Homeless Assistance Providers and Clients

NVVRS National Vietnam Veterans Readjustment Survey

OEF Operation Enduring Freedom

OIF Operation Iraqi Freedom
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OR Odds ratio

p Probability

PIT Point-in-time

PTSD Post-traumatic stress disorder

SAMHSA Substance Abuse and Mental Health Services Administration

SSDI Social Security Disability Insurance

SSI Social Security Supplementary Income

TANF Temporary Assistance for Needy Families

TCE Targeted Capacity Expansion

USICH United States Interagency Council on Homelessness

VA Veterans Affairs

VAMC VA Medical Center

VHA Veterans Health Administration

VISN Veterans Integrated Service Networks