Less than half of people experiencing homelessness regularly used illicit drugs in the prior six months. The most common drugs used by this population aren't opioids but methamphetamines. And a significant percentage of people who are homeless and use drugs regularly have tried, but have been unable to receive treatment.
These are some of the findings revealed in a UC San Francisco-led report of more than 3,200 adults experiencing homelessness, the largest representative study of the homeless population since the National Survey of Homeless Assistance Providers and Clients was published in 1996.
Only around 37% reported regular drug use in the prior six months. And 25% had never used drugs at any point in their lifetime. About 65% of people experiencing homelessness reported using illicit drugs regularly, or at least three times a week, at some point in their life.
The paper appears Feb. 19 in the medical journal JAMA.
"Our research shows there is an increased risk of becoming homeless if you use drugs; and that homelessness itself increases drug use because people use it as a coping strategy," said Margot Kushel , MD, director of the UCSF Benioff Homelessness and Housing Initiative (BHHI) and senior author of the report.
But despite public perception, Kushel said, most people who are homeless aren't using drugs regularly.
Patterns of homelessness and substance use
We need to reduce barriers to substance use treatment and that includes prioritizing people's ability to return to housing."
The report uses data from the 2023 California Statewide Study of People Experiencing Homelessness (CASPEH), which is a representative study of homeless adults conducted by BHHI.
The CASPEH team administered 3,200 surveys and 365 in-depth interviews with people experiencing homelessness between October 2021 and November 2022 in eight regions of California representing urban, rural and suburban areas. BHHI has been releasing a series of reports since 2023 on various aspects of homelessness, including pregnancy, aging and intimate partner violence.
More than 770,000 people in the U.S. were experiencing homelessness on a single night in January 2024, an 18% increase from 2023, according to a report from the U.S. Department of House and Urban Development released in December.
California accounts for 12% of the U.S. population but has a disproportionate size - 28% - of the country's homeless population, and nearly half of those experiencing unsheltered homelessness.
While the study is limited to California, the researchers said the results are likely to reflect similar patterns across the nation, particularly in regions with a high percentage of unsheltered homeless people.
Methamphetamine use dominates, but opioids remain a challenge
Despite the focus on fentanyl and other opioids over the past decade, methamphetamine use outpaced opioids among people experiencing homelessness, the report found.
Of study participants, 33% said they had used meth at least three times a week in the past six months and about 10% reported regular opioid use. Just 3% said they used cocaine regularly, which was more commonly used in the 1990s. People, particularly those who are unsheltered, may use meth to help them stay alert in unstable situations, the researchers said.
While drug use increases the risk of homelessness, becoming homeless increases one's risk of using illicit drugs, the researchers found. About 42% of all participants said they began using drugs regularly before they became homeless for the first time, and 23% said they began using drugs regularly after becoming homeless for the first time.
Many respondents expressed that they wanted to receive treatment for their substance use disorder but were unable to access it. Just 7% said they were in treatment in the weeks surrounding the study, but 21% said they wanted to get treatment and were trying but were unable to get the care they needed.
About 20% experienced a non-fatal overdose at least once in their lifetime, with 10% of people experiencing an overdose while they were homeless. The researchers suggested that targeted distribution strategies could improve access to the medication naloxone, which can reverse an opioid overdose.
"We know how to treat substance use, but it is hard to do that while people are still homeless. We need to reduce barriers to substance use treatment and that includes prioritizing people's ability to return to housing," said Ryan Assaf , PhD, MPH, assistant professor in the Division of Health Equity and Society at UCSF and first author of the study.
Authors: Co-authors include Meghan D. Morris, PhD, MPH, Morgan M. Philbin, PhD, MHS, and Priest Martinez, all of UCSF; and Elana R. Straus of Yale School of Medicine, Yale University.
Funding: The research was supported by BHHI, the Blue Shield Foundation of California, the California Healthcare Foundation, and the National Institute on Aging (2K24AG046372).
