What are the true medical concerns facing unsheltered homeless adults?

Estimates of behavioral and physical health conditions among unsheltered populations are often used to guide policy initiatives for healthcare and housing, yet robust, disease-specific prevalence estimates remain limited. We address this gap by leveraging multiple data sources to generate more reliable estimates of specific disease conditions for unsheltered adults.

We triangulate data from three sources in Los Angeles County, which has the largest unsheltered population in the US: a probability-based survey of adults experiencing homelessness (n = 898), and electronic health records from two field-based medical providers (n = 1683; n = 527). We report univariate estimates by source and summarize across sources.

Across sources, median prevalence was 40% for mental health conditions (range: 40%-61%) and 33% for substance use conditions (range: 31%-43%). Post-traumatic stress disorder and major depression were the most common mental health conditions (median 22%), and stimulant use disorder was the most common substance use condition (median 17%). Physical health conditions were more common than both mental health and substance use conditions overall (median 57%; range: 49%-73%).

These findings underscore that housing and health care are complementary components of care and support, integrating field-based medical services with permanent housing investments.