The Royal College of Psychiatrists has issued an urgent warning for people taking common mental health medications, including antidepressants, mood stabilisers, and antipsychotics, during the UK's current heatwave. Dr Daniel Harwood, chair of the Royal College of Psychiatrists’ Planetary Health and Sustainability Committee, highlighted that these patients may be particularly vulnerable to high temperatures.
Medications Affect Body Temperature Regulation
Many common psychiatric medications affect the hypothalamus, the brain region responsible for regulating internal body temperature. This can impair the body's ability to recognise overheating and trigger natural cooling mechanisms. Some medications also dull the sense of thirst, increasing dehydration risk.
Dr Harwood stated: “With the Met Office issuing a ‘risk to life’ weather warning for parts of the UK, people with mental health conditions and taking medications including antidepressants, mood stabilising or antipsychotic medications must take special care. We know people with mental health conditions — especially severe mental illnesses such as schizophrenia and bipolar disorder — often have worse underlying physical health than the general population, so they may be more vulnerable to sunburn, dehydration and heat stroke.”
Dehydration Risks and Lithium Toxicity
Dehydration is a particular concern as it can increase sensitivity to medication side effects. Dr Harwood noted: “Becoming dehydrated can be a particular problem at the moment, as it can increase sensitivity to the effects of some medicines, such as constipation for people on clozapine. People taking lithium also need to drink plenty of fluids to support their kidney function.” Dehydration can raise lithium concentration in the bloodstream, pushing it out of the safe range and risking toxicity.
Rising Risks During Extreme Heat
Research shows increased risks for people with mental illness during extreme heat, including a 1.5% rise in suicide incidence and a 9.7% rise in psychiatric hospital admissions, according to the Royal College of Psychiatrists.
Dr Harwood advised: “I’d urge all people, but especially those with a mental illness, to make a concerted effort to stay cool and hydrated, use plenty of sun block and avoid going out during the hottest parts of the day. And if you feel physically unwell, please contact your pharmacy, mental health team or seek urgent medical advice.”
Common antidepressants prescribed on the NHS include fluoxetine, sertraline, citalopram, and paroxetine. The heatwave has already broken June temperature records.
