Development and Testing of a Just-in-Time Adaptive Smart Phone Intervention

An estimated 6.2% of US adults will be homeless at some point in their lifetime. 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. A significant contributor to morbidity and mortality among homeless adults is the high prevalence of alcohol use. Approximately 33% of homeless adults have current alcohol dependence, a rate nearly 8 times that of the general population. Although shelter-based treatments are common, compliance is typically poor. Identifying factors that influence alcohol use would significantly improve the 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. Traditional assessment methodologies may also provide biased and/or inaccurate estimates due to recall biases and errors in memory, particularly in this complicated population. 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. 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.

This pilot study will develop and test a "just-in-time" adaptive intervention to reduce alcohol use among homeless adults. Phase I 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 for an AUD. Phase II will use this information to create a risk algorithm and tailored treatment messages that anticipate and intervene to prevent alcohol use. Phase II will modify an existing app, previously validated for smoking cessation, to create the intervention. Phase III will pilot test the newly developed app for utility, satisfaction, and preliminary effectiveness in a group of 40 homeless adults with an AUD who are enrolled in shelter-based treatment. Alcohol consumption will be validated via a transdermal alcohol sensor (i.e., SCRAM) worn by participants in Phases I and III.

The central hypothesis is that alcohol use is strongly affected by moment-to-moment risk and protective factors. This study will be able to use EMAs to identify and automatically intervene during moments when people are at high risk for drinking. This hypothesis is based on preliminary findings among homeless, justice-involved, and socioeconomically disadvantaged safety-net hospital patients. If effective, this smartphone app could significantly improve treatment engagement, drinking outcomes, and quality of life among homeless adults with AUDs.

This project will: