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:
Liz Leicester
or Deborah Hart in the Communications
Department.
Telephone: 020 7235 2351 Extensions. 6298 or 6127
References:
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