If you take an antipsychotic, summer is not just uncomfortable — it can be medically risky. Most antipsychotics impair the body's normal ways of cooling itself, and as climate-driven heat waves become more frequent and intense, hospitals are seeing rising rates of heat-related illness in patients on these medications. This guide explains why, and what to do about it.
Antipsychotics blunt your ability to feel and respond to heat — so the most important rule is to plan for heat before you feel it.
Why heat is harder on antipsychotic patients
Several mechanisms combine:
- Anticholinergic effects reduce sweating. Many antipsychotics (especially clozapine, olanzapine, chlorpromazine, and quetiapine) have meaningful anticholinergic activity.
- Hypothalamic effects alter the brain's thermostat. Dopamine blockade interferes with normal temperature regulation.
- Sedation can blunt awareness of how hot you actually are.
- Dehydration risk rises when medications also cause dry mouth, urinary changes, or constipation.
- Polypharmacy with anticholinergic medications (benztropine, diphenhydramine, tricyclic antidepressants) compounds risk.
The FDA includes heat-related warnings in the labelling of most antipsychotics. The CDC specifically lists antipsychotic and anticholinergic medications as risk factors for heat-related illness.
What heat illness actually looks like
Heat exhaustion (early)
- Heavy sweating (or, on antipsychotics, oddly little sweating)
- Weakness, dizziness, headache
- Nausea
- Cold, clammy, pale skin
- Fast, weak pulse
Action: get to air conditioning, drink water steadily, lie down, cool the back of your neck and wrists. If symptoms don't improve in 30 minutes, go to an emergency department.
Heat stroke (medical emergency)
- Body temperature 40°C / 104°F or higher
- Hot, dry, red skin (or sometimes still sweating)
- Confusion, altered mental state, slurred speech
- Loss of consciousness, seizure
Body temperature is over 40°C (104°F), or there is confusion, fainting, severe headache, vomiting, or seizure. Call 911 or your local emergency number. Heat stroke is fatal without rapid treatment.
Daily summer practices
Hydration
Drink water across the day — not just when you feel thirsty (thirst signal can be blunted on these medications). A general guideline is 2–3 litres a day in hot weather, more if you exercise or are outdoors. Avoid heavy alcohol and limit caffeine, both of which are dehydrating. If you have heart or kidney conditions, talk to your prescriber about your specific hydration target.
Cool environments
Air conditioning saves lives in heat waves. If your home doesn't have AC:
- Identify a nearby cooling centre, public library, mall, or community centre with AC
- Use fans (helpful below 35°C / 95°F; less effective above)
- Keep blinds closed during the hottest part of the day
- Take cool showers or baths, especially in late afternoon
- Sleep with a damp towel or cool pack near you
NAMI and many local mental health authorities maintain heat-wave resource lists; ask your case manager or call SAMHSA's helpline (1-800-662-HELP) for local options.
Timing outdoor activity
Walk, exercise, or run errands early morning or after sunset. Avoid strenuous activity between 11 am and 5 pm during heat waves. If you exercise outdoors, see our guide on exercise and schizophrenia for safer alternatives during summer.
Clothing and sun
Loose, light-coloured, breathable fabrics. A wide-brimmed hat. Sunscreen — many antipsychotics also cause photosensitivity (see our piece on photosensitivity and antipsychotics).
Medication considerations
Do not stop or change your antipsychotic on your own to "cope with summer." Stopping antipsychotics is the single biggest predictor of relapse. But do talk to your prescriber at the start of the warm season about:
- Whether your dose can be optimised
- Whether anticholinergic medications (benztropine, trihexyphenidyl, diphenhydramine for sleep) can be reduced — these significantly worsen heat tolerance
- Whether you should adjust hydration habits
- Whether you have a particular heat-sensitive condition (e.g., neuroleptic malignant syndrome history)
Living without air conditioning
Many people with schizophrenia live in housing without AC, often for financial reasons. This is a structural risk that deserves explicit conversation with your case manager or treatment team. Some local utilities offer summer crisis assistance programs. Public health departments in heat-prone cities maintain cooling-centre lists. Don't wait for a heat wave to make the plan — identify your fallback today.
Watch for early warning signs
In hot weather, warning signs of dehydration and heat exhaustion can blur with side effects. Headache, fatigue, dizziness, and confusion can all be either. When in doubt, treat for heat first: cool down, hydrate, lie flat. If symptoms don't resolve, get medical evaluation.
For caregivers
If you are supporting someone with schizophrenia through summer, check in daily during heat waves. Ask specifically: Are they drinking water? Is their AC on or are they at a cooling centre? Have they been outside in midday sun? People on sedating medications often underestimate how hot they actually are. A daily phone call can prevent an emergency.
This article is for educational purposes only and is not medical advice, diagnosis, or treatment. Always consult a qualified mental health professional. If you or someone you know is in crisis, call or text 988 in the US, or your local emergency number.