Primary care providers should screen patients with co-occurring disorders for being unhoused and also for unstable housing, a recent study recommended, as consumers with co-occurring disorders who were unhoused or unstably housed were found to have worse mental health and substance use symptom severity compared with stably housed individuals. Health outcomes could be improved and health care costs could be reduced by addressing housing instability in primary care settings, the researchers concluded.

Key findings were as follows:

• Unhoused people were more likely to be younger, have received less education, have never married, and have not taken prescribed medication for opioid use disorder in the past 30 days than both unstably housed and stably housed people.
• Mental health risks were higher for both the unhoused and the unstably housed compared to the stably housed. 
• People with unstable housing situations—such as those staying temporarily with friends or in shelters—had more severe opioid problems and riskier drug use behaviors than those with stable housing.
• The researchers found no clear link between housing status and alcohol use problems.

The researchers used standardized assessments to measure opioid use severity. Higher scores indicate higher severity. The scores tied to the following patterns based on housing status. Homeless people had the highest scores, indicating the most severe opioid use disorder issues and the riskiest behaviors that could lead to overdose. People with unstable housing—like those moving between temporary housing—scored in the middle range, with somewhat less severe issues than homeless individuals but higher than those with stable homes. People with stable housing had the lowest scores, indicating the least severe opioid use problems and the lowest scores for opioid overdose risk.

The researchers analyzed data from a randomized controlled trial, Collaboration Leading to Addiction Treatment and Recovery from other Stresses, which tests the Collaborative Care Model for primary care consumers with opioid use disorder and co-occurring depression and/or post-traumatic stress disorder (PTSD).

• “Unhoused” is defined as “not living in stable housing in the past three months.”
• “Unstably housed” is defined as “living in stable housing but being worried or concerned about loss of housing in the next three months.”

Differences in baseline characteristics across the housing groups were assessed for a total of 797 randomized individuals. A total of 13% of the sample was currently unhoused, 24% were unstably housed, and 63% were stably housed. The researchers used two standardized assessments of mental health severity and three to assess substance use severity.

These findings were presented in Association Between Housing Status And Mental Health And Substance Use Severity Among Individuals With Opioid Use Disorder And Co-Occurring Depression And/Or PTSD, by Lauren Kelly, Grace M. Hindmarch, Katherine E. Watkins, Colleen M. McCullough, and colleagues. According to the study, the goal was to examine the cross-sectional associations between housing status (currently unhoused, unstably housed, and stably housed) and mental health and substance use severity among primary care consumers with co-occurring disorders. 

The full text of Association Between Housing Status And Mental Health And Substance Use Severity Among Individuals With Opioid Use Disorder And Co-Occurring Depression And/Or PTSD was published on August 8, 2025, by BMC Primary Care. A free copy is available (accessed August 21, 2025). 

For more information, contact: Warren Robak, Office of Media Relations, RAND Corporation, 1776 Main Street, Post Office Box 2138, Santa Monica, California 90401-2138; 310-393-0411; Fax: 310-393-4818; Email: robak@rand.org; Website: http://www.rand.org/