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The Royal College of Psychiatrists Improving the lives of people with mental illness

People with serious mental illness ‘at greater risk of death during hot weather’

Embargoed until 01 June 2012

People with serious mental illness are at increased risk of death during hot weather, according to new research published today in the June issue of the British Journal of Psychiatry.


The findings add to the growing evidence that people with mental illness are a vulnerable group during hot weather, and have implications for public health strategies during heat waves.

The study used the General Practice Research Database to identify people with a diagnosis of psychosis, dementia, alcohol misuse and drug misuse who had died in England over a 10-year period from 1998-2007. In total, there were 22,562 deaths –a mean of 6.18 deaths each day. Daily temperature data across the same period for all monitoring stations in England were downloaded from the British Atmospheric Data Centre.

The researchers found that patients with mental illness faced an increased risk of death of about 5% per 1oC increase in temperature above 18oC. This is greater than the risk for the general population, which has an increased risk of around 3% per 1oC increase in temperature.

The increased risk of death was more marked among younger patients, those living in southern and eastern parts of England, those who had been diagnosed with drug or alcohol problems, and those who were taking antipsychotics.


The researchers believe there are several biological and social factors that may increase mortality among people with mental illness during hot weather. People with mental illness are more likely to be socially isolated or living in institutional care – both of which are risk factors for heat-related death. Antipsychotic medication can also affect people’s ability to regulate their body temperature by reducing sweating.


People with substance misuse problems may be vulnerable during hot weather because alcohol depresses the central nervous system causing dehydration, and opiates can affect the body’s physiological response to heat.


Given that the elderly are often associated with high death rates during heat waves, the researchers were surprised to find that patient under 65 were at greater risk of death than older patients. However, they believe this may be because the majority of older people in the study had dementia, and may have received better care during periods of hot weather than younger people with alcohol or drug misuse problems.


Consultant psychiatrist and lead researcher Dr Lisa Page, of Sussex Partnership NHS Foundation Trust, said: "We found a marked increase in risk of death for people with psychosis, dementia and substance misuse during hot weather, and suggests that people with mental illness may be a vulnerable group. Some public health strategies, such as the English ‘Heatwave Plan’ already identify patients with mental health problems as being a high risk group. But more attention may need to be paid to patients with alcohol and drug misuse problems, who are often not under the care of mental health services."


Senior researcher Professor Louise Howard, of King’s College London Institute of Psychiatry, added: "Given that global temperatures will continue to rise and the frequency of heat waves is predicted to increase in the years to come, these findings suggest that the consequences of climate change may be felt disproportionately by the mentally ill."

For further information, please contact:
Sarah Nevins
Press & Social Media Officer
Telephone: 020 3701 2543
Claire McLoughlin
Media & Communications Manager 
Telephone: 020 3701 2544
Out of hours contact number: 07860 755896



Page L, Hajat S, Kovats RS, Howard LM. Temperature-related deaths in people with psychosis, dementia and substance misuse. British Journal of Psychiatry, 2012; 200: 485-490


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