The Connection Between Homelessness and Addiction in California

California is home to the largest unhoused population in the United States. According to the California Interagency Council on Homelessness, the state’s January 2023 Point-in-Time Count identified approximately 181,000 people experiencing homelessness on a single night — nearly 28 percent of the national total. Alongside this crisis, substance use disorders remain prevalent among people without stable housing, creating a complex, deeply intertwined challenge that demands compassionate, evidence-based responses.

Understanding the relationship between homelessness and addiction matters for several reasons. It shapes how we respond as communities and individuals. It challenges assumptions about who becomes homeless and why. And most importantly, it points toward the solutions that actually work — solutions that California is increasingly adopting.

The Relationship Is Not What Most People Assume

When people hear “homelessness and addiction,” they often assume a simple causal story: people use drugs, lose their jobs and housing, and end up on the street. While this pathway does occur, the relationship is far more complex, and this assumption can lead to policies and attitudes that do more harm than help.

Research published in peer-reviewed journals and cited by the Substance Abuse and Mental Health Services Administration (SAMHSA) consistently shows that the relationship between homelessness and addiction is bidirectional:

Addiction can contribute to homelessness. Substance use disorders can lead to job loss, family estrangement, legal problems, and financial crisis — all of which can end in housing instability. This pathway is real.

Homelessness can drive substance use. Living without shelter is traumatic. Exposure to violence, chronic stress, social isolation, untreated pain, and the need to stay awake for self-protection all create conditions where substance use can feel like the only available coping mechanism. Many people who develop substance use disorders do so after losing their housing, not before.

Shared underlying causes: Both homelessness and substance use disorders are strongly associated with childhood trauma, mental illness, poverty, lack of social support, and systemic inequities including racism and discrimination in housing and employment. These root causes — not a simple A-causes-B relationship — explain much of the overlap.

The National Institute on Drug Abuse (NIDA) emphasizes that treating addiction as a character flaw or personal failure ignores the structural and neurological realities of substance use disorders. The same is true for homelessness.

The Scale of the Challenge in California

The overlap between homelessness and substance use in California is significant. The California Department of Public Health and the California Interagency Council on Homelessness both report that a substantial portion of unhoused Californians have co-occurring substance use disorders, mental health conditions, or both. Point-in-Time survey data and shelter intake assessments consistently show these overlapping needs.

Los Angeles County — home to the largest unhoused population of any county in the nation — has seen a dramatic increase in overdose deaths among people experiencing homelessness. The Los Angeles County Department of Public Health has identified encampments and interim housing sites as settings where fentanyl exposure is particularly acute, requiring targeted harm reduction responses.

San Francisco, Oakland, Sacramento, and San Diego all face similar challenges. Across the state, people experiencing homelessness face barriers to addiction treatment that housed individuals do not: no mailing address required for some intake processes, no phone for appointment reminders, no safe place to store medications, and no reliable transportation to outpatient programs.

What Works: A Housing-First Approach

The most evidence-supported approach to homelessness among people with substance use disorders is called Housing First. Supported by rigorous research and endorsed by SAMHSA, the Centers for Disease Control and Prevention (CDC), and leading addiction medicine organizations, Housing First provides stable housing without requiring sobriety or treatment compliance as a precondition.

This approach is not about giving up on people. It is about recognizing that treatment and recovery are much harder — often impossible — for people who are simultaneously trying to survive without shelter. When people have a stable place to live, they are more likely to engage in addiction treatment, more likely to achieve and maintain sobriety, and less likely to cycle through emergency rooms and jails.

California has invested significantly in Housing First approaches through:

Project Homekey: A state-funded program that converts hotels, motels, and other buildings into permanent supportive housing. As of 2024, Project Homekey has created more than 15,000 units of housing across California.
No Place Like Home: A state bond program funding permanent supportive housing for people with serious mental illness who are experiencing homelessness.
CalAIM Community Supports: California’s Medi-Cal transformation initiative (CalAIM) now funds housing navigation, tenancy sustainment services, and transitional housing as Medi-Cal benefits — recognizing that housing stability is healthcare.

Harm Reduction: Meeting People Where They Are

For people experiencing homelessness who have active substance use disorders, harm reduction strategies can save lives while building the trust and connection that leads to treatment engagement over time.

Harm reduction approaches in California include:

Naloxone distribution: Many California cities and counties distribute naloxone (Narcan) free of charge at shelters, drop-in centers, libraries, and through mobile health units. Naloxone reverses opioid overdoses and has saved thousands of lives in California.

Fentanyl test strips: Now legal in California, fentanyl test strips allow people to check substances for fentanyl contamination before use, reducing overdose risk.

Syringe services programs (SSPs): Authorized under California law, SSPs reduce the transmission of HIV and hepatitis C among people who inject drugs. SAMHSA and the CDC both recognize SSPs as effective public health tools that also serve as entry points to treatment.

Mobile outreach: Many California counties operate mobile health units and street medicine teams that provide healthcare, mental health services, and connection to treatment directly to encampments and gathering spots.

Low-barrier shelters: Shelters that do not require sobriety for entry provide critical safety while enabling engagement with services.

Pathways from the Streets to Recovery

California has programs specifically designed to support people experiencing homelessness in accessing addiction treatment:

Sobering Centers: Cities including San Francisco and San Diego operate sobering centers — safe, supportive spaces where people who are intoxicated can recover without being taken to emergency rooms or jails. Many sobering centers provide connections to longer-term treatment.

Street Medicine: Programs affiliated with USC and other institutions send medical teams directly to encampments to provide healthcare, including addiction treatment, to people who will not or cannot access clinic-based care.

County Alcohol and Drug Programs (ADPs): Every California county is required to provide a pathway to substance use treatment for Medi-Cal beneficiaries, including those experiencing homelessness. Many county ADPs have outreach workers who specifically serve the unhoused community.

Recovery Residences: Sober living homes that accept residents who are transitioning from homelessness, jail, or treatment are available across California. The California Association of Addiction Recovery Resources (CAARR) maintains a directory of recovery housing.

Medi-Cal Access for People Experiencing Homelessness

A critical development for unhoused Californians is that Medi-Cal eligibility does not require a permanent address. California allows people experiencing homelessness to use a shelter address, a social service agency address, or a designated “transient” address to enroll. Under CalAIM, case managers and care coordinators actively help unhoused Medi-Cal members enroll and maintain coverage.

Once enrolled, unhoused Californians can access the full range of Medi-Cal substance use disorder benefits, including residential treatment, medications for addiction treatment, and outpatient counseling.

Take the First Step

If you are experiencing homelessness and struggling with substance use, you deserve help — regardless of where you are sleeping tonight. If you know someone in this situation, reaching out on their behalf could save their life.

Call the California Addiction Hotline today. Our counselors are trained to work with people in all circumstances, including those experiencing homelessness. We can help identify low-barrier treatment options, connect you with Medi-Cal enrollment assistance, and find programs that meet you where you are.

You do not have to have everything figured out. You do not need a permanent address. You just need to make one call.

Sources: California Interagency Council on Homelessness; California Department of Public Health; Substance Abuse and Mental Health Services Administration (SAMHSA); National Institute on Drug Abuse (NIDA); Centers for Disease Control and Prevention (CDC); California Department of Health Care Services (DHCS)