Development and Testing of a Just-in-Time Adaptive Smart Phone Intervention
Phase: NA
Conditions: Alcohol Use Disorder, Treatment, Homelessness
Sponsor: University of North Texas Health Science Center

Study Protocol, NCT03746808, Page  
 
1 
 
 
 
 
 
 
 
Study Protocol with Statistical Analysis Plan (SAP) 
 
Development and Testing of a Just-in-Time Adaptive Smart Phone Intervention to Reduce 
Drinking Among Homeless Adults 
 
NCT03746808 
 
Date of Continuing Review Approval: 11/02/22 
 
Date of Document: 11/02/22 
 
 

Study Protocol, NCT03746808, Page  
 
2 
A. Specific Aims  
This project will: 
1. Use phone-based ecological momentary assessment (EMA) to identify environmental 
(i.e., geolocation), cognitive, and behavioral antecedents of alcohol use among 80 
homeless adults with an AUD who are receiving shelter-based treatment. 
2. Develop a “just-in-time” adaptive intervention to reduce alcohol use, including an alcohol 
use risk algorithm and corresponding theory-based treatment messages. 
3. Examine feasibility, acceptability, and preliminary effectiveness of a just-in-time adaptive 
smartphone app among 40 homeless adults with an AUD who are receiving shelter-
based treatment. 
 
B. Background and Significance  
An estimated 6.2% of US adults will be homeless at some point in their lifetime.1 Homeless 
adults have higher rates of disease, greater risk of interpersonal violence, shorter life 
expectancies, and disproportionately higher health care utilization and costs compared to 
housed individuals.2-5 A significant contributor to morbidity and mortality among homeless 
adults is the high prevalence of alcohol use.6-9 Approximately 33% of homeless adults have 
current alcohol dependence,10,11 a rate nearly 8 times that of the general population.12 
Although shelter-based treatments are common,13 compliance is typically poor.9 Identifying 
factors that influence alcohol use would significantly improve our ability to develop effective 
interventions and engage homeless adults in treatment.  
Relatively little is known about the environmental, cognitive, and behavioral antecedents of 
alcohol use in homeless adults. Like other subgroups, alcohol use has most often been 
examined using traditional lab/clinic based assessment methods that are not well suited to 
capturing the complicated street-level interactions experienced by most homeless adults.14,15 
Ecological momentary assessment (EMA), in which handheld devices (e.g., smartphones) 
are used to capture moment-to-moment experience, is currently the most accurate way to 
measure phenomena in natural settings.14,16-18 Additionally, recent technological advances 
have made it possible to collect continuous geolocation data alongside EMA. Researchers 
can now link environmental risks and protective factors to outcomes, without reliance on 
subjective reporting alone.19,20  
This study will develop and test a “just-in-time” adaptive intervention to reduce alcohol use 
among homeless adults. During Phase I, we will use smartphones and passive sensing to 
monitor geolocation, psychosocial variables (e.g., stress, urge to drink), and alcohol use in a 
group of 80 homeless adults enrolled in shelter-based treatment. In Phase II, we will use this 
information to create a risk algorithm and tailored treatment messages that anticipate and 
intervene to prevent alcohol use (there are no human subjects in Phase II). We will modify 
an existing app, previously validated for smoking cessation, to create the intervention. In 
Phase III, we will pilot test the newly developed app for utility, satisfaction, and preliminary 
effectiveness in a group of 40 homeless adults enrolled in shelter-based treatment. In Phase 
I, alcohol consumption will be validated via a transdermal alcohol sensor (i.e., SCRAM) worn 
by all participants. If effective, this smartphone app could significantly improve treatment 
engagement, drinking outcomes, and quality of life among homeless adults with AUDs.  
 
 

Study Protocol, NCT03746808, Page  
 
3 
Figure 1. Phase I and III Flowcharts 
Phase I (n=80)     
  
Phase III (n=40)   
 
In Phase I, this project will provide urgently needed data on the ways that street-level factors 
interact with alcohol use in a homeless population. In Phase II, this information will be used 
to create treatment messages that support motivation and self-efficacy.96,97 Motivational 
(derived from MI and the transtheoretical model) and self-efficacy (derived from SCT) 
themed messages are commonly used in technology-based alcohol interventions,98 but 
mobile interventions have the additional strength of fostering self-regulation during high-
craving situations through triggering goal salience and re-evaluation of short vs. long-term 
goals.99 For example, SMS interventions for AUD have focused on encouraging self-
regulation and planning prior to drinking episodes.100,101 For those who continue to attend 
shelter-based treatment, the messages will reinforce common treatment concepts. For those 
who discontinue shelter-based treatment, the messages may serve as a primary intervention 
(or at least a reminder of past concepts) in order to short-circuit alcohol use before it occurs. 
C. Experimental Design and Methods  
 
1) Methods and Procedures  
Setting 
Phases I and III will be conducted at the Bridge Homeless Recovery Center (i.e., the Bridge) 
located in Dallas, TX. The Bridge’s 80 employees and on-site partners provide services 
(e.g., meals, mental health and substance abuse counseling, care management, housing 
placement, job readiness training) to approximately 85% of all homeless adults in Dallas 
County each year. The Bridge conducts approximately 366 new intakes each month and 
approximately 32% of all new intakes report current “problems with alcohol.” We expect 
Phase I enrollment to take approximately 9 months (n=80) and Phase III enrollment to take 
approximately 6 months (n=40).  
Screening Procedures 
Homeless adults receiving treatment at Metrocare at the Bridge will be given a flyer that 
briefly outlines this study. Interested individuals will be scheduled for a screening visit to 
determine study eligibility. We may give participants a card to remind them of their 
appointment time. Prior to screening, potential participants will receive information about this 
voluntary study and will be informed that Bridge and Metrocare services are not contingent 
upon study enrollment. Interested participants will sign a consent form prior to completing 
the screener. The screener includes questions about demographics, alcohol use, use of 
technology, and other questions.  
Screening
Baseline
Equipment 
visit
4 Weeks of EMA + alcohol 
monitoring
(2 week equipment check)
4 Week 
follow-up
Screening
Baseline
Equipment 
visit
4 Weeks of EMA + alcohol 
monitoring + messages
(2 week equipment check)
4 Week 
follow-up

Study Protocol, NCT03746808, Page  
 
4 
We will notify subjects in real-time whether or not they are eligible to be in the study and can 
proceed with the baseline survey. Eligible participants will complete a separate consent form 
and then complete the in-person baseline assessments as described below. On the baseline 
they will provide identifiers that will be linked to the screener information We will retain 
screening data for both eligible and ineligible participants.  
Participants 
Participants will be eligible if they: 1) receive a score 
of 8 or above on the AUDIT (a measure of alcohol 
dependence); 2) report consuming at least 1 drink of 
alcohol in the past week; 3) are receiving treatment 
at Metrocare; 4) are willing and able to complete the 
baseline and follow-up visits; 5) score ≥ 4 on the 
REALM-SF indicating > 6th grade English literacy 
level (i.e., a 7th grade reading level is necessary to 
complete assessments; 12% to 14% of those 
screened for Projects Advance and Aspire had 
REALM scores <7th grade reading level; <1% of 
Bridge guests are non-English speakers), and 6) 
score >24 on the Mini-Mental State Exam indicating 
no substantial cognitive impairment.  Individuals will 
be excluded from participating if they indicate on the 
screener that they would be uncomfortable wearing 
an alcohol sensing bracelet for 4 weeks (Phase I 
only). Individuals will be excluded from participating 
in Phase III if they participated in Phase I. 
Individuals who meet the study inclusion criteria and 
provide informed consent will complete the baseline 
assessment and 4-week follow-up assessments in a 
space that is set aside at the Bridge specifically for 
this study. All participants will receive a smartphone 
and SCRAM at the first equipment visit, returning 
the devices at the end of the 4-week period.  
In-person Assessments 
In-person assessments will be administered at the 
baseline and 4-week visits. The surveys will ask 
about demographics, social network, experiences 
with homelessness, stress/victimization, social 
support, mood, health, quality of life and substance 
use. Some of the questions are asked to evaluate 
the effect of the intervention (e.g., alcohol, consequences, satisfaction); other questions are 
asked to determine whether there are factors that moderate (e.g., self-rated mental/physical 
health diagnosis, stress, status, religious participation) or mediate (e.g., sleep, stress, 
coping) the effects of the intervention. The locator form and homelessness timeline follow-
back will be administered at baseline only. Data will be collected on laptop/tablet computers 
using Questionnaire Development System (QDS) software. QDS utilizes a computer-
administered self-interview format where each item appears on the computer screen while 
the program simultaneously reads the item (participants use a mouse or touch screen to 
Table 1. In person assessment 
measures. 
Background/History 
Locator Form 
Demographic Information 
Questionnaire* 
Subjective Social Status102 
Brief Homelessness Questionnaire 
Homelessness Timeline Follow-
Back103* 
Health/Mental Health 
SF-12110 
Health Related Quality of Life111 
Self-Rated Health 
Tobacco Questionnaire 
Inadequate Sleep 
Time Line Follow-Back112 (past 
month alcohol) 
Short Inventory of 
Consequences113 
Stress/Affect 
Personal Victimization104 
Perceived Stress Scale – Short 
Version105 
Urban Life Stress Scale 
Depression108 
Interpersonal/Intrapersonal 
Interpersonal Support Evaluation 
List 
Brief COPE 
Religious Participation 
Treatment Satisfaction 
EMI Satisfaction Survey ** 
*Baseline only 
**Follow-up only 
 

Study Protocol, NCT03746808, Page  
 
5 
select answers only after QDS reads each item). Participants wear headphones so that 
others do not hear the survey items. Staff will be available to help participants who may 
have difficulty. We estimate that the baseline visit will take approximately 1 to 2 hours to 
complete, and the follow-up visit will take approximately 50 to 80 minutes to complete.  
Equipment Visits 
Approximately 2-3 days after the baseline assessment, participants will receive the 
cellphone (including instructions on how to complete the phone assessments), and will be 
fitted with the SCRAM bracelet (Phase I only). In order for the SCRAM to function properly, 
we will breathalyze participants at this equipment visit to ensure a zero BAC. Participants 
who do not register a zero BAC will be asked to come back later (or another day if BAC is 
very high) at a time when it is estimated to be zero. We will review the functioning of both 
devices, and participants will sign form indicating that they understand how to care for the 
devices. Additionally, participants will be asked to complete an equipment visit at 2 weeks 
(the mid-point of the study period) to verify that the phone and SCRAM are working properly. 
At the 2-week visit, people can receive payment for the phone assessments they have 
completed thus far. There are no research assessments at the equipment visits.  
Phone Procedures 
A Samsung Galaxy Core Prime smartphone (or equivalent) will be loaned to each 
participant so that they may complete EMAs. Participants 
navigate through the EMA program and enter data by 
touching their response on the screen. Participants will be 
able to call (e.g., if they have problems completing EMAs) and 
receive calls from research staff through the smartphone free 
of charge. During their participation in the study:  
a. Subjects are not responsible for any costs related to the 
cell phone (e.g., lost, stolen, damaged and/or data 
overages). 
b. Phone services (data I phone package) will be terminated 
if the phone is lost or stolen, or once the subject 
completes the intervention. 
c. One replacement will be provided in the event the phone is 
lost, stolen or damaged. 
d. Subjects can charge their phones at the Bridge, or in any 
other local establishments. 
 
Phone Assessments 
Smart Phone Training. Participants will receive hands-on 
training on study phone use and will watch a brief step-by-
step video tutorial (created by the researchers) at the first 
equipment visit that demonstrates use of the study phone and 
app features. This video will also be preloaded onto the home 
screen of study phones. We have achieved high EMA 
compliance rates (i.e., 82% of all EMAs completed) using this 
protocol in a sample of homeless adults.23,121 
Three types of EMAs will be used: daily diary, random 
Table 2. EMA measures. 
Daily Diary 
Sleeping Arrangements  
Social Support and 
Interactions 
Treatment Attendance 
Current Stressors & 
Perceived Stress 
Alcohol Consumption 
Other Substance Use 
Core/Random/Event 
Sampling  
Affect/Stress 
Urge to Drink 
Alcohol/Money Availability 
Social setting/Location 
Recent Alcohol 
Consumption 
Expectancies 
Abstinence Motivation 
Abstinence Self-Efficacy 
New/Ongoing Stressful 
Events*  
Reasons for Drinking* 
Modified Conflict Tactics 
Scale 
*Drinking assessments 
only 

Study Protocol, NCT03746808, Page  
 
6 
sampling, and event sampling. Random sampling and daily diary EMAs will be initiated by 
the phone. The phone will audibly and visually cue these EMAs for 30 seconds. If the 
participant has not responded after 5 prompts, the assessment will be recorded as missed. 
Event sampling is initiated by participants if/when they consume the first drink in a day. On 
average, random and event sampling assessments take 2 minutes to complete and daily 
diary assessments take less than 5 minutes to complete.  
Daily Diary EMAs will be completed each day (prompted 30 minutes after waking time); 
questions will ask about the previous day and current experiences. Alcohol consumption will 
be assessed with the item “Did you drink any alcohol yesterday?” If the participant answers 
“yes,” he/she will be prompted to indicate the type and quantity of the alcohol that was 
consumed. Additional items will assess sleeping arrangements from the prior night, social 
support and types of social interactions, discrete stressors, other substance use, and 
treatment session attendance. Daily Diary assessments will cease after 4 weeks. 
Random Sampling will occur 4 times each day, during each participant’s normal waking 
hours. Participants will rate their affect by indicating the extent to which they agree or 
disagree with each of thirteen statements: I feel irritable, happy, content, angry, sad, 
worried, miserable, restless, stressed, hostile, calm, bored, and depressed. In addition, 
participants will describe their current environment (e.g., shelter, work, outside, bar) and 
social setting (e.g., alone, with others, with others who are drinking). Alcohol urges, 
alcohol/money availability, drinking start/stop time, recent drinking, expectancies, motivation 
for abstinence, and abstinence self-efficacy will also be assessed during random sampling. 
Random assessments will cease after 4 weeks. 
Event Sampling will be available to participants on demand. Participants will be instructed to 
click the “Record Drink” button if/when they have their first drink of a day. Drinking 
assessments will include all items from the random assessments and will query about the 
reinforcing value of the drink(s) and causes of the drinking episode. 
Geolocation. Consistent with previous work,19,20,51 smartphones will collect geo-location 
coordinates about every 5 minutes. The aim of this study is to identify psychological, social, 
and contextual variables that predict drinking and heavy drinking days. Previous studies 
have found that continuous “breadcrumb” tracking can be used to identify important health 
risk factors.19,20,58 We will remove all personal information from the phone once it is returned 
to us. 
Alcohol Sensor 
Biosensors can provide a continuous estimate of blood alcohol concentration (BAC) based 
on the concentration of alcohol in perspiration on the skin.52-59 The device with the most 
extensive evaluation is the SCRAM bracelet (Alcohol Monitoring Systems, Littleton, CO), 
which is worn on the ankle. In Phase I, all participants will wear the SCRAM for 4 weeks. 
SCRAM has an electrochemical sensor that samples the vapor near the skin every 30 
minutes for ethanol, and stores readings for later retrieval. Data from the SCRAM is 
downloaded to a computer via USB cable, using a 16-digit key and password-protected 
software. The SCRAM is water resistant and cannot be removed without cutting the strap. 
The SCRAM system provides alerts if the bracelet sensors detect an obstruction or other 
tampering. At the 2-week equipment check-in, our staff will review participant readings and 
any alerts and will address any malfunction or evidence of tampering. To mitigate any 
potential risk to subjects while wearing the SCRAM monitor: 

Study Protocol, NCT03746808, Page  
 
7 
a. Law enforcement officers cannot obtain the information even if subjects are taken to jail. 
SCRAM data are encrypted and need to be connected to the research computer in order 
to download the data. 
b. The Certificate of Confidentiality (COC) protects investigators from having to disclose 
SCRAM data to law enforcement or anyone else. 
c. Subjects can cover up the ankle monitor with their clothes and always decline 
participating in the study. 
d. Subjects will be informed through the consent form that the SCRAM ankle bracelet may 
draw unwanted attention by law enforcement (and possibly others) to them. 
e. Subjects will be provided with a laminated card that describes their participation as a 
research subject (they may also choose to carry a copy of the consent form with them). 
 
App Testing (Phase III only) 
The phone-based app that will be tested in Phase III will have multiple components 
including: 1) an on-demand “Tips” function/button; 2) a “Helpful Websites” function/button; 3) 
a “Call Staff” function/button; and 4) an algorithm that will use recent EMA responses and 
geolocation to assess current risk for alcohol use and automatically push relevant tailored 
messages to help them avoid drinking. The phone will record date/time when each of the 
above components is accessed. As the app is not yet designed, the IRB would need to 
approve the content of the app prior to Phase III testing. 
 
Tips Function. Clicking this on-demand option will open a new window that will enable 
individuals to get useful tips related to: “Benefits of Sobriety,” “Motivational Messages,” 
“Alcohol Refusal Skills,” and “Managing Urges.” For instance, when the “Managing Urges” 
tips option is clicked, participants will receive a suggestion on how to cope with their current 
urge to drink. This function will enable participants to access tailored messages at any time. 
Participants may view additional tips by simply clicking the “Next” button. Type and number 
of tips viewed will be recorded by the smartphone. Other topics for tips will be identified via 
examination of Phase I participants’ survey and EMA data. 
Helpful Websites Function. Clicking this option will open a menu of potentially useful 
websites (e.g., Dallas public transit routes, Google maps, online support groups [e.g., 
Alcoholics Anonymous]). 
Call Staff Function. Clicking this option will connect participants to study staff if they 
encounter problems with the study phone and for scheduling/rescheduling follow-up 
appointments. 
Message Content. Smartphones will push tailored messages based on the risk algorithm 
score at the end of each EMA. We anticipate that participant responses that indicate low risk 
for imminent alcohol use (e.g., within the next 4 hours) will prompt delivery of level 1 
messages that primarily focus on increasing motivation for abstinence, avoiding 
people/places/things that may trigger alcohol use, benefits of sobriety, advice on ways to 
escape high risk situations, and advice to seek support from others.23 Level 2 messages will 
be delivered at the end of EMAs where the algorithm determines that there is heightened 
risk for imminent alcohol use (e.g., within the next 4-8 hours). These messages will focus on 
in-the-moment distraction, reframing, immediate help-seeking, planning, and other tools to 
reduce craving. Participants will receive level 3 messages when they report recent drinking. 
Level 3 messages will focus on reframing the drinking episode as a learning experience and 
considering strategies for handling the situation differently in the future. 

Study Protocol, NCT03746808, Page  
 
8 
Risk Algorithm. The algorithm used to guide the just-in-time treatment messages will be 
similar to the algorithm that was developed for the Smart-T smoking cessation app.25 
Specifically, the algorithm will estimate risk for alcohol use using variables identified in 
Phase I. Variables that predict alcohol use will be identified and, through an iterative 
process, will be weighted based upon their relation to lapse. We will also consider 
parameters (e.g., slopes and/or volatility of key variables) that are identified in the GLMMs 
described above as potential algorithm components. For instance, a pattern of increasing 
negative affect or stress over 8 hours may be a significant predictor of alcohol use. Finally, 
an innovative feature of this risk algorithm will be the inclusion of geolocation data. We 
anticipate that some locations will significantly increase an individual’s risk for alcohol use 
(e.g., previously tagged drinking locations), and thus a person’s “current location” will be an 
important part of the risk algorithm.  
D. Statistical Analysis Plan 
Acceptability of App (Phase III only) 
A brief questionnaire will assess the initial feasibility and acceptability of the app. 
Specifically, in a final follow-up visit after participating in the EMA, participants will report on 
the helpfulness of the app and if the number of prompts on the app were appropriate. We 
will use statistical tests to determine if participants found the app to be helpful and if they 
would recommend it to others. 
 
Effectiveness of App (Phase III only) 
 
We will compare Phase III participants (i.e., those who received Metrocare, EMAs, and the 
app features including tailored treatment messages) to Phase I participants (i.e., those who 
received Metrocare and EMAs only) to examine the preliminary effectiveness of the app. 
Specifically, we will compare Phase I and Phase III participants’ percent drinking days 
(PDD) and percent heavy drinking days (PHDD; >=5 drinks for men; >=4 drinks for women) 
using appropriate generalized linear models. We will consider the study phase as the 
parameter of interest estimating the treatment effect, adjusting for relevant covariates (e.g., 
gender, race, baseline AUD severity).  
 
Phase I and Phase III 
 
EMA data will be measured repeatedly and are thus correlated within subjects. Thus, our 
analytic approach will include generalized linear mixed model regression analysis (GLMM), 
a flexible analytic approach with wide use in health sciences research.134 GLMM can handle 
fixed and random effect model parameters, nested designs, and repeated measures with 
various correlation structures.135,136 GLMM can also handle normal and non-normal 
outcomes such as dichotomous alcohol use variables, different variance functions, as well 
as unbalanced designs where the number of observations varies across individuals. 
Examples of planned GLMM analyses include: 1) testing if random assessments of alcohol 
urges or measures of affect (each aggregated to one rating per day) predict daily drinking 
status after controlling for relevant covariates (e.g., gender, race/ethnicity, depression), 2) 
testing if protective factors (e.g., social support, positive interpersonal interactions, prosocial 
location) predict alcohol use, and 3) examine trends of number of drinks and drinking days 
over time, accounting for dependencies of within-person repeated measures. 
 
In addition, EMA data will allow us to examine other important questions like: 1) agreement 

Study Protocol, NCT03746808, Page  
 
9 
between SCRAM, TLFB and EMA reports of alcohol use in this sample, and 2) the effect of 
episodic events (e.g., exposure to violence or other stressors) on self-efficacy and mood 
and what impact that has on alcohol use.