Homelessness and Mental Health Statistics: The Data

On a single night in January 2025, nearly three-quarters of a million people in the United States had nowhere permanent to live. Some slept in emergency shelters or transitional housing. Hundreds of thousands more slept in cars, tents, doorways, and other places not meant for human habitation.

Homelessness and mental health are deeply intertwined — but the relationship is often misunderstood. The popular assumption that most homelessness is “caused by” mental illness overstates the story in one direction while missing the fuller picture: for many people, serious mental illness and substance use are both reasons someone loses stable housing and consequences of living without it. This article walks through what the federal data actually show, drawing on the U.S. Department of Housing and Urban Development’s (HUD) annual counts and the Substance Abuse and Mental Health Services Administration’s (SAMHSA) work on the homeless population.

If you or someone you know is struggling or in crisis, help is available. Call or text 988 to reach the 988 Suicide & Crisis Lifeline, available 24/7.

The Scale: How Many People Are Homeless?

Each year, HUD coordinates a nationwide Point-in-Time (PIT) count — a snapshot of how many people are experiencing homelessness on one night in late January. It is the most authoritative national measure available, and it distinguishes between people who are sheltered (in emergency shelters, transitional housing, or safe havens) and those who are unsheltered (living in places not designed for habitation).

*Sheltered figure for 2025 derived from HUD’s reported total and unsheltered counts. Source: HUD 2024 and 2025 AHAR, Part 1.

Two things stand out. First, the numbers are large: roughly 745,652 people were homeless on that night in 2025, including 266,320 living unsheltered (HUD, 2025). Second, unsheltered homelessness — the most visible and often most dangerous form — accounts for more than a third of the total. People who are unsheltered face far greater exposure to violence, illness, untreated medical conditions, and premature death than those in shelters.

These snapshots also undercount the full scope of housing instability. The PIT count captures a single night; over the course of a year, many more people cycle in and out of homelessness, and still more live doubled-up, couch-surfing, or one missed paycheck away from losing their home. Our overview of the housing-insecure population covers that broader group.

Chronic Homelessness: The Most Vulnerable Subgroup

Not all homelessness looks the same. HUD tracks a specific, higher-need category called chronic homelessness, defined as having a disabling condition plus either continuous homelessness for at least one year, or at least four episodes of homelessness in three years totaling 12 months. The “disabling condition” in that definition frequently includes serious mental illness, substance use disorder, or a chronic physical health problem — which is why this subgroup sits at the center of the mental health conversation.

In January 2024, about 152,585 individuals experienced chronic patterns of homelessness — the highest count on record, and roughly one in three of all homeless individuals (HUD, 2024). Around 65% of them were unsheltered, meaning the people with the greatest health needs are also the least likely to have even the minimal protection of a shelter bed. And the trend has been sharply upward: chronic homelessness rose 81% between 2013 and 2025 (HUD, 2025).

This matters for mental health because the chronically homeless population is where serious mental illness and substance use disorders are most concentrated. Understanding who these 152,585 people are — and why they remain unsheltered — is inseparable from understanding untreated mental illness in America.

The Mental Health Burden Among People Experiencing Homelessness

Here the data become both striking and easy to misread, so precision matters. SAMHSA estimates that approximately 30% of people experiencing chronic homelessness have a serious mental illness, and that around two-thirds have a primary substance use disorder or another chronic health condition (SAMHSA). These figures describe the chronically homeless population specifically — the highest-need subgroup — not everyone who is homeless.

To see how far that departs from the general population, it helps to set it against the national baseline:

Among all U.S. adults, 5.6% had a serious mental illness in 2024 (SAMHSA, 2024). Among people experiencing chronic homelessness, the share is roughly five times higher. The concentration of substance use disorder and other chronic conditions is higher still, with around two-thirds affected.

A few points of interpretation keep these numbers honest. The 30% figure applies to chronic homelessness, which is about a third of homeless individuals — so it should not be read as “30% of all homeless people have serious mental illness.” Mental illness and substance use are most concentrated in the unsheltered, chronically homeless population, exactly the group that is hardest for services to reach. And a diagnosis alone does not explain how someone became homeless; income, housing costs, eviction, domestic violence, and the loss of a support network all play major roles. Mental illness is one thread in that fabric, not the whole cloth.

A Two-Way Street: Cause and Consequence

Perhaps the most important thing the data reveal is that the relationship runs in both directions. SAMHSA frames mental illness and substance use as both risk factors for and consequences of homelessness — not simply one causing the other.

As a cause: Serious mental illness can disrupt employment, strain relationships, and make it harder to navigate the systems that keep housing stable — paying rent on time, responding to eviction notices, maintaining benefits. When those supports fall away and no safety net catches a person, housing can be lost. Substance use disorders can follow a similar path.

As a consequence: The reverse is at least as powerful. Losing your home is itself a severe, sustained trauma. Chronic sleep deprivation, constant vigilance for safety, exposure to violence, and the erosion of dignity and routine can trigger or worsen depression, anxiety, PTSD, and substance use — even in people who had no prior diagnosis. For someone already living with a mental health condition, the instability of homelessness makes treatment nearly impossible to sustain: appointments are missed, medications are lost or stolen, and there is no stable address for follow-up care.

This feedback loop is why homelessness is so difficult to exit, and why it concentrates in the chronically homeless population. It also intersects with other systems. Many people cycle between the street, emergency rooms, and jails without ever reaching sustained care — a pattern we examine in our analysis of incarceration and mental health statistics.

Breaking the loop requires addressing both housing and health at once. But access to care remains a fundamental obstacle. People experiencing homelessness face the widest version of the mental health treatment gap, and a nationwide shortage of mental health providers means that even those who seek help may wait weeks or months for an appointment they have no stable way to keep. For a population without a mailing address, a phone plan, or transportation, every barrier that affects the general public is magnified.

Frequently Asked Questions

How many people are homeless in the United States?

HUD’s Point-in-Time count found 745,652 people experiencing homelessness on a single night in January 2025, including 266,320 who were unsheltered. The prior year’s count, in January 2024, was 771,480 people (HUD, 2024; HUD, 2025).

What percentage of homeless people have a mental illness?

According to SAMHSA, approximately 30% of people experiencing chronic homelessness have a serious mental illness, and around two-thirds have a primary substance use disorder or other chronic health condition. These figures describe the chronically homeless subgroup — the highest-need population — rather than everyone who is homeless. For comparison, 5.6% of U.S. adults overall had a serious mental illness in 2024.

What is chronic homelessness?

HUD defines chronic homelessness as having a disabling condition together with either continuous homelessness for at least one year, or at least four episodes of homelessness within three years that total 12 months. About 152,585 individuals met this definition in January 2024 — roughly one in three homeless individuals — and around 65% of them were unsheltered.

Does mental illness cause homelessness, or does homelessness cause mental illness?

Both. SAMHSA describes mental illness and substance use as both risk factors for and consequences of homelessness. Serious mental illness can contribute to the loss of stable housing, while the trauma, instability, and danger of being homeless can trigger or worsen mental health and substance use conditions. The two reinforce each other, which is part of why chronic homelessness is so hard to exit.

Why are so many people with mental illness unsheltered rather than in shelters?

Mental illness and substance use disorders are most concentrated in the unsheltered, chronically homeless population — the group hardest for services to reach. Around 65% of chronically homeless individuals were unsheltered as of January 2024. Barriers to care, provider shortages, and the instability of homelessness itself make sustained treatment extremely difficult for this group.

Is homelessness getting better or worse?

The single-night total dipped slightly from 771,480 in 2024 to 745,652 in 2025, but chronic homelessness has risen sharply — up 81% between 2013 and 2025 — and reached its highest recorded level. In other words, the most vulnerable subgroup has grown even when overall counts have not.

Sources

1. U.S. Department of Housing and Urban Development. 2025 Annual Homelessness Assessment Report (AHAR) to Congress, Part 1: Point-in-Time Estimates. HUD; 2026. https://www.hud.gov/news/hud-no-26-037

2. U.S. Department of Housing and Urban Development, Office of Policy Development and Research. 2024 AHAR Part 1: Point-in-Time Estimates of Homelessness. HUD; 2024. https://www.huduser.gov/portal/sites/default/files/pdf/2024-AHAR-Part-1.pdf

3. Substance Abuse and Mental Health Services Administration. Homelessness Programs and Resources. SAMHSA. https://www.samhsa.gov/communities/homelessness-programs-resources

4. Substance Abuse and Mental Health Services Administration. SAMHSA Releases Annual National Survey on Drug Use and Health (NSDUH). SAMHSA; 2025. https://www.samhsa.gov/newsroom/press-announcements/20250728/samhsa-releases-annual-national-survey-on-drug-use-and-health