App aids substance use recovery in vulnerable populations

(Press-News.org) Although drug overdose deaths declined in the U.S. last year, the rate of substance use disorder is rising, and the problem remains undertreated: Fewer than one in five people with substance use disorder report that they’ve received any treatment for it. An especially vulnerable group are those who use substances and do not have stable housing, who research shows are both far more likely to experience overdose and much less likely to receive treatment for their condition compared to those who have secure housing.

A new study has shown that a mobile app developed by researchers at Washington University School of Medicine in St. Louis is effective at helping this at-risk population take steps toward recovery. Among people who misused opioids or other substances and lacked stable housing, those who used the app reported significant reductions in their opioid and non-opioid substance use after a month compared to those who did not engage with the app. App users also improved their health literacy and showed improvements in key mental health measures associated with successful treatment compared to their baseline measurements.

The study was published Feb. 1 in Drug and Alcohol Dependence.
Vidya Eswaran, MD, an assistant professor in the WashU Medicine Department of Emergency Medicine and lead author on the study, knows firsthand from her work in the Barnes-Jewish Hospital emergency department that patients struggling with housing insecurity have distinct needs, including inconsistent access to care and greater mental health burdens, that can make substance-use treatment harder to sustain than for patients in stable living situations.

“There is a lot of overlap with people who are experiencing housing insecurity and have substance use disorders, so it is important to make sure that the interventions that we provide are addressing the needs of this specific subpopulation,” said Eswaran. “Some people might think that these groups would not have a mobile phone or the digital literacy to use an app like this, but the results show people were not only using it, but also getting benefit from it.”

App inspired by online addiction-support communities The uMAT-R (pronounced “you matter”) app was developed and launched in 2018 by a team led by Patricia Cavazos-Rehg, PhD, a professor in the WashU Medicine Department of Psychiatry and senior author of the new study. It was designed to provide free, easy-to-access support for people with any substance use disorder, including misuse of opioids, stimulants and hallucinogens, with the goal of reducing overall overdose deaths. It works on iOS and Android smartphones.

uMAT-R provides information on treatment options and social support resources within the user’s community, as well as user-specific tools such as a sobriety tracker. It also provides educational content on managing withdrawal, maintaining sobriety and improving mental health. Participants can communicate through a chat function with trained coaches (called “e-coaches”) who are available Monday through Friday and offer advice and encouragement.

The app is not yet publicly available; participants are generally enrolled while receiving care for substance use disorder at a treatment center or other health care facility in Missouri, including Barnes-Jewish Hospital, where patients are screened and enrolled through the WashU Medicine Department of Emergency Medicine’s Emergency Care Research Core staff. Other participants have requested enrollment through the research team after learning of the app through word of mouth. Cavazos-Rehg, who is also on the faculty of the WashU School of Public Health, noted that such peer-to-peer information sharing is characteristic of the online substance use disorder communities that provided the initial inspiration for the app.

“I observed how folks use social media venues to support each other, even during times when they were feeling most alone or stigmatized,” said Cavazos-Rehg. “They would ask questions on social media about clinical care and seek out resources for mental health help. This inspired me to develop a tool for people who are going through mental health problems or are in recovery support.”

Cavazos said that a long-term funding commitment from the Missouri Department of Mental Health brought the project to life. “They recognized that a lot of life happens outside of traditional in-person mental health and substance use treatment settings, and that mobile apps can be affordable, accessible tools that can improve the health and wellbeing of people, especially during critical times when other types of help may not be readily available,” she said.

The new study included data from a subset of uMAT-R users who were enrolled in the app between 2020 and 2024. Of 972 initial enrollees, more than 70% self-identified as having insecure housing — which could include living in shelters or on the street, living in a treatment facility or hospital, or staying in someone else’s home. Of those individuals, 378 completed a follow-up survey after a month of using the app, forming the study’s sample.

Participants completed an intake survey to assess substance use patterns, cravings and baseline level of health literacy — defined as the ability to find appropriate health information and resources in order to make health care decisions. The survey also included two measures of mental health, both correlated with depression: perceiving themselves to be a burden to those around them, and having a sense of not belonging. One month later, participants completed a new survey to identify any changes in these measures, and this information was correlated with patterns of app usage.

The researchers found that participants who used uMAT-R were about 50% less likely to have used non-opioid illicit drugs after a month compared to those who didn’t log on. And participants who messaged with the e-coach were about 50% less likely to report opioid use than those who did not use the function. Higher levels of app use were associated with greater reductions in illicit drug use overall. uMAT-R use was also associated with reduced substance cravings and lower perceived burdensomeness, and using the chat function was associated with improving health literacy and reducing feelings of social alienation and isolation, when compared to the baseline intake survey.

“These results speak to the promise of what mobile health and digital health technologies can bring to the treatment of hard-to-reach populations,” said Eswaran, who is planning a similar study for recently incarcerated people with substance use disorders. Going forward, “there’s potential to think creatively about how we adapt and refine tools like this even more to support vulnerable populations.”

 

Eswaran V, Dong F, Li X, Szlyk HS, Dell NA, Kasson E, Williams J, Cavazos-Rehg PA. Leveraging a digital health intervention to improve recovery outcomes among people with substance misuse experiencing housing insecurity. Drug and Alcohol Dependence. Feb. 1, 2026. DOI: 10.1016/j.drugalcdep.2026.113022

The uMAT-R app is funded in part by the Missouri Department of Health & Senior Services. Funding for this study was provided by the Substance Abuse and Mental Health Services Administration grant 1H79TIO80271, the National Institute on Drug Abuse grants R34DA050453 and R44DA055161 and the National Institute of Nursing Research grant T90NR021683. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.

About WashU Medicine

WashU Medicine is a global leader in academic medicine, including biomedical research, patient care and educational programs with more than 3,000 faculty. Its National Institutes of Health (NIH) research funding portfolio is the second largest among U.S. medical schools and has grown 83% since 2016. Together with institutional investment, WashU Medicine commits well over $1 billion annually to basic and clinical research innovation and training. Its faculty practice is consistently among the top five in the country, with more than 2,000 faculty physicians practicing at 130 locations. WashU Medicine physicians exclusively staff Barnes-Jewish and St. Louis Children’s hospitals — the academic hospitals of BJC HealthCare — and Siteman Cancer Center, a partnership between BJC HealthCare and WashU Medicine and the only National Cancer Institute-designated comprehensive cancer center in Missouri. WashU Medicine physicians also treat patients at BJC’s community hospitals in our region. With a storied history in MD/PhD training, WashU Medicine recently dedicated $100 million to scholarships and curriculum renewal for its medical students, and is home to top-notch training programs in every medical subspecialty as well as physical therapy, occupational therapy, and audiology and communications sciences.

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