When it’s really hot, mental health can suffer | Harvard T.H. Chan School of Public Health

July 13, 2026 - 18:08

As temperatures climb to dangerous levels, the effects on physical health are well known: heatstroke, dehydration, and cardiovascular strain. But according to Amruta Nori-Sarma, a researcher at the Harvard T.H. Chan School of Public Health, extreme heat also poses a serious threat to mental well-being. The connection is often overlooked, yet the data shows a clear pattern.

When the mercury rises, emergency room visits for anxiety, mood disorders, and even suicidal ideation tend to spike. The reasons are complex. High heat can disrupt sleep patterns, increase irritability, and amplify feelings of stress. For people already managing conditions like depression or bipolar disorder, the added physical discomfort can push symptoms past a tipping point. Heat also affects the brain's neurotransmitters and can interfere with medications, making them less effective or harder to tolerate.

Nori-Sarma points out that vulnerable populations, including those without air conditioning or stable housing, face the greatest risk. The problem is expected to worsen as climate change drives more frequent and intense heat waves. Public health officials are now urging communities to treat extreme heat as a mental health crisis, not just a physical one. Simple steps like staying hydrated, using cooling centers, and checking on neighbors can help, but broader systemic changes are needed to protect those most at risk.