Amy Arias, MMS, MD/MPH candidate MS4 UACOMP
Arizona is growing fast — and so is its unhoused population. As housing costs rise, resources lag behind demand, and extreme heat becomes deadlier each year, the people most affected are often those least equipped to navigate the system: individuals living with severe mental illness (SMI).
Homelessness is not just a housing issue. It is a public health crisis, a mental health crisis, and a fiscal crisis for the state of Arizona.
The Scope of the Crisis
As of January 2024, nearly 15,000 people in Arizona were experiencing homelessness, according to the state’s annual Point-in-Time count. While there has been a slight decrease in unsheltered homelessness, this data likely underrepresents the true scope of the problem due to difficulties with self-reporting, loss of follow-up, and limited outreach capacity.
At the same time, Arizona faces a shortage of approximately 133,000 affordable housing units for low-income renters. Even someone working full-time may still be unable to afford fair market rent. For families, the math becomes impossible.
Children are not spared. One in five unhoused individuals in Arizona is a child, and the majority of unhoused adults are between the ages of 18 and 64.
Why Arizona’s Climate Makes Homelessness More Dangerous
Arizona’s environment turns homelessness into a life-threatening condition.
In Maricopa County alone, 45% of all heat-related deaths in 2023 occurred among people experiencing homelessness, with heat-related mortality increasing more than 50% from the prior year. Extreme heat doesn’t just worsen chronic illnesses, it increases overdose risk, worsens psychiatric symptoms, and overwhelms emergency departments.
For individuals with severe mental illness, exposure to extreme weather compounds already elevated health risks.
Severe Mental Illness and Homelessness: A Vicious Cycle
Arizona’s Medicaid program (AHCCCS) currently serves over 65,000 individuals with a severe mental illness designation, a number that has increased by more than 50% since 2015. More than 11% of people with SMI experienced homelessness in a single year.
Mental illness makes housing stability harder to achieve due to:
unemployment and poverty,
difficulty adhering to treatment plans,
long waitlists for housing,
and high rates of hospital readmission.
At the same time, homelessness worsens psychiatric illness, increases substance use, disrupts medication access, and raises mortality risk.
The result is a self-perpetuating cycle: untreated mental illness leads to homelessness, and homelessness worsens mental illness.
Substance Use, Injury, and Early Death
Unsheltered homelessness is strongly associated with increased substance use — particularly alcohol — and higher rates of dual diagnosis (mental illness plus substance use disorder).
Arizona spent over $776 million on substance use disorder treatment in 2024, much of it funded through Medicaid. Alcohol-related treatment was the single largest category.
Mortality data paints an even starker picture. Individuals with SMI who are unhoused die younger and at much higher rates than the general population. Accidental death, suicide, overdose, and chronic liver disease are all more common — especially among unsheltered individuals.
Men with SMI experience particularly high mortality rates, suggesting a need for more targeted housing and support services.
Hospitals Are Becoming the Safety Net of Last Resort
When housing is unavailable, hospitals absorb the consequences.
Emergency departments and inpatient psychiatric units often house individuals who are medically or psychiatrically stable but cannot be safely discharged due to lack of housing. The median waiting time for permanent housing for someone with SMI in Arizona is one to two years.
This leads to:
prolonged hospital stays,
high 30-day readmission rates,
increased inpatient psychiatric spending,
and avoidable strain on healthcare workers and systems.
Inpatient psychiatric expenditures for SMI patients in Arizona totaled hundreds of millions of dollars in 2024 alone.
The Financial Case for Permanent Supportive Housing
Arizona currently spends nearly $17,000 per person per year on care for individuals with SMI — much of it on crisis services, inpatient treatment, and emergency care.
Yet evidence consistently shows that permanent supportive housing reduces hospitalizations, emergency visits, incarceration, and overall public spending. Housing improves medication adherence, stabilizes mental health, and saves lives.
Despite this, Arizona’s investment in permanent supportive housing stays insufficient, and waitlists continue to grow.
Existing Programs — and Their Limits
Arizona has made meaningful efforts:
emergency shelters,
rapid rehousing programs,
street outreach,
prevention initiatives,
and pilot data-tracking tools.
But these programs cannot compensate for a fundamental shortage of housing units.
Proposed investments in new data systems and secure behavioral health facilities may improve coordination, but data alone does not house people. Without sufficient housing stock, individuals with SMI will continue to cycle through hospitals, shelters, and the streets.
A Path Forward
Addressing Arizona’s unhoused crisis — particularly among those with severe mental illness — requires prioritizing housing as essential infrastructure for health.
That means:
expanding permanent supportive housing,
reducing waiting times,
investing in affordable housing development,
and pairing housing with integrated mental health and substance use services.
This is not just a moral imperative. It is a financially responsible strategy that reduces strain on hospitals, lowers Medicaid expenditures, and improves quality of life statewide.
Housing Is Health Care
Arizona’s unhoused crisis cannot be deferred. With continued population growth and worsening climate conditions, the cost of inaction will only rise — in dollars and in lives.
When we house our most vulnerable residents, we don’t just provide shelter. We improve health outcomes, reduce public spending, and build a more resilient Arizona.
Housing is health care — and Arizona cannot afford to ignore that any longer.