The Heat Is Getting Into People's Heads
When extreme heat dominates the news, the coverage tends to focus on heat stroke, dehydration, and physical risk. But a growing body of research — and clinical observations from psychologists at major health systems — is documenting a parallel toll that receives far less attention: heat makes mental health worse, measurably and consistently, across multiple disorders and demographic groups.
Psychologist Susan Albers, PsyD, of the Cleveland Clinic, explained the mechanism this week: "Heat mimics anxiety — symptoms such as sweating, racing heart, dizziness. These are common to being overheated and anxious, and your brain can mistake the two." When the body sends physical distress signals that mirror anxiety, the brain's threat response can escalate — even in people who do not normally experience anxiety — triggering a feedback loop of physiological arousal and emotional distress.
Why This Matters
The mental health toll of extreme heat is not a minor side effect. It shows up in emergency room data, crisis hotline records, and population-level suicide statistics in ways that are now well-documented across multiple independent research programs.
A study published in JAMA Psychiatry found an 8% increase in mental health emergency department visits on the hottest days of summer compared with the coolest days — an increase that ranged from 5% to 11% depending on the specific condition. Substance use disorders, anxiety disorders, mood disorders, schizophrenia-related disorders, self-harm, and childhood behavioral disorders all showed elevated ER visits on extreme heat days.
A February 2026 study published in PLOS Mental Health analyzed crisis hotline data from 2019 through 2023 and found that suicide-related help-seeking increased dramatically with rising nighttime temperatures: a 55% increase at the 95th percentile of nighttime heat, and a 166% increase at the 99th percentile. Every degree matters — and the research found that the effects on crisis calls were detectable before temperatures hit what most people would describe as "extreme."
What We Know So Far
The biological pathways linking heat to mental health are multiple and reinforcing.
Core body temperature and brain chemistry. Research shows that patients with depression already have higher core body temperatures relative to healthy controls, as NPR reported in a July 2, 2026 feature on heat and mental health. In extreme heat, this baseline difference may be amplified. Dr. Joshua Wortzel, a psychiatrist at the Hartford HealthCare Institute of Living and director of the HEAT-MIND Lab, told NPR: "A lot of patients with mental illness at baseline have difficulties regulating their temperature." When ambient temperatures rise, people whose thermoregulatory systems are already compromised face the highest biological load.
Cortisol and the stress response. Cleveland Clinic's Dr. Albers noted that in extreme temperatures, the body works harder to cool itself, which triggers the release of cortisol — the primary stress hormone. Elevated cortisol directly worsens anxiety, disrupts sleep, impairs working memory, and can trigger or worsen depressive episodes.
Sleep disruption. Heat is one of the most reliable disruptors of sleep quality, particularly deep sleep. Poor sleep amplifies every mental health symptom, reduces emotional regulation, lowers frustration tolerance, and increases impulsivity and aggression.
Loss of outdoor coping. Exercise, time in nature, and social activity in public outdoor spaces are among the most effective evidence-based buffers against anxiety and depression. Extreme heat systematically eliminates access to these activities — forcing people indoors, reducing physical movement, and increasing social isolation.
What New Research Showed This Week
A new multi-country study published this week and reported by Deseret News analyzed 2.6 million hospitalizations and found a measurable surge in mental health-related crisis incidents following heat waves — making it the first study of this scale to document the heat-mental health relationship across multiple countries simultaneously.
The study found that hot weather drives irritability, impulsivity, and depressive episodes and is linked to increased rates of psychotic episodes and aggression. Jane Gilbert, the world's first Chief Heat Officer, a government position established in Miami-Dade County in 2021, told researchers: "Extreme heat can make people more depressed or irritable, it can bring on psychotic outbreaks, and people on certain psychiatric medications are more sensitive to heat."
That last point — psychiatric medications and heat sensitivity — is critically important and often overlooked in public health guidance. Antidepressants, antipsychotics, and mood stabilizers can impair the body's ability to regulate temperature. People taking these medications face a compounded risk during heat events.
Where the Risk Is Highest
The mental health burden of extreme heat is not evenly distributed. Research consistently identifies elevated risk in:
- People with pre-existing mental health conditions — depression, bipolar disorder, schizophrenia, anxiety disorders, substance use disorders
- People taking psychiatric medications that impair thermoregulation, including antidepressants, antipsychotics, and lithium
- People without access to air conditioning, particularly in low-income urban neighborhoods and rural areas
- Older adults living alone, who face both physical and social vulnerability during extended heat events
- Young people, particularly adolescents and college-age adults, who show elevated crisis call rates during extreme nighttime heat
- Workers in outdoor occupations who cannot escape heat exposure during working hours
The February 2026 PLOS Mental Health study specifically identified youth, women, and Black clients as groups showing elevated mental health mentions at high temperatures, and youth were also most strongly associated with increases in isolation during heat events.
Symptoms and Warning Signs to Watch For
It can be difficult to distinguish heat-driven mental health changes from baseline symptoms — which is part of what makes this risk underrecognized. Watch for:
- Unusual irritability, anger, or agitation disproportionate to circumstances
- Worsening anxiety or panic that does not respond to usual coping strategies
- Depressed mood, tearfulness, or emotional flatness that appears new or suddenly worse
- Sleep disruption that persists even in air-conditioned environments (cortisol dysregulation can outlast the immediate heat exposure)
- Increased conflict with others — arguments, impulsive reactions
- Withdrawal from social contact and usual activities
- Thoughts of self-harm or hopelessness, particularly when combined with isolation, sleep deprivation, and medication disruption
For people on psychiatric medications: watch for signs of heat sensitivity, including excessive sweating, confusion, or elevated body temperature even in moderate heat, and contact your prescribing clinician promptly.
What You Can Do Now
- Prioritize access to cooling during extreme heat. If you do not have air conditioning, identify the nearest cooling center in your city or county and plan to use it during peak afternoon heat hours.
- Maintain regular sleep schedules and protect sleep quality. Use blackout curtains, fans, or cooling devices at night. Sleep deprivation is one of the fastest triggers for worsening mental health symptoms.
- If you take psychiatric medication, ask your prescribing clinician whether your medications affect heat tolerance and what signs should prompt a call.
- Maintain social contact during heat events. Check in by phone or video call if going out is not possible. Isolation dramatically worsens heat-related mental health effects.
- If you or someone you know is experiencing a mental health crisis, call or text the 988 Suicide and Crisis Lifeline at any time. Crisis counselors are available 24/7.
- Physical cooling — a cool shower, cold water on the wrists, a damp cloth on the neck — can provide meaningful mental relief by reducing core body temperature.
Cost and Access: What Patients Should Know
Many cities operate free cooling centers during heat emergencies. Check your local emergency management or health department website for locations. The American Red Cross shelter finder can also locate nearby cooling sites.
For mental health support, the 988 Lifeline is free and available in English and Spanish. The Crisis Text Line (text HOME to 741741) provides free, confidential text-based crisis support. Both are available at no cost regardless of insurance status.
People experiencing a psychiatric emergency made worse by heat — including confusion, extreme agitation, or inability to care for themselves — should call 911 or go to an emergency room immediately.
What Happens Next
The scientific community is moving quickly to better understand heat's mental health impact, driven in part by the reality that summers are getting hotter and heat waves are getting longer in the United States. Dr. Wortzel's HEAT-MIND Lab at Hartford HealthCare is one of several research programs now dedicated specifically to this intersection of climate and mental health. Updated federal guidance on heat and mental health from the CDC and the Substance Abuse and Mental Health Services Administration (SAMHSA) is anticipated as more population-level data accumulates from 2026's summer seasons.
The Bottom Line
Extreme heat is a mental health hazard — not a metaphor, but a documented, measurable driver of psychiatric emergencies, crisis calls, aggression, and suicide risk. For the tens of millions of Americans currently experiencing dangerous heat conditions, and particularly for those with existing mental health conditions or taking psychiatric medications, the risks are real and the protective steps are practical. Stay cool, stay connected, and know that the 988 Lifeline is available around the clock if you or someone you know needs immediate support.
