Firmly cementing the notion that the British are obsessed with the weather, this fortnight’s post considers how far climate might affect our mental health. Usually, when we think about the links between our external environment and how we feel, we think of Seasonal Affective Disorder (SAD), or ‘the winter blues’. But what about our mental wellbeing at other times of year? Over the last few weeks, Britain has been hit by heat waves interspersed with some impressive thunderstorms, both of which have been identified as possible influences upon mental health.
In the 19th century, Sussex Asylum’s Chaplain ‘laboured assiduously at meteorological observations’, claiming to find a correlation between atmospheric pressure as measured by the barometer, and fits experienced by epileptic patients. In America in the 1930s, W.F. Peterson and M.E. Milliken suggested in The Patient and the Weather that the incidence of neurosyphilitic conditions could be mapped onto the major storm tracks of North America – an intriguing idea, but one that a reviewer regretted was ‘very hypothetical’. Storms, though, were also identified as possible factors in suicidal behaviour by C.A. Mills in 1934, who suggested that the pressure and temperature changes caused by large storms might produce ‘mental instability’. Excessive heat had long been identified as a factor in mental ill health – seen, for example, in those soldiers admitted to asylums whose condition was attributed to ‘sunstroke’ suffered in India or Africa.
But what about today? When a heat wave occurs, we often hear warnings in the press about the need to pay special attention to the health of young children and the elderly. The Department of Health’s Heatwave Plan also identifies those with mental illnesses as another at-risk group – not in terms of the direct effect of heat on their mental wellbeing, but their increased susceptibility to heat stroke. This may be due to individuals living in an institutional setting where provisions for dealing with a heat wave are inadequate; being isolated in the community and less likely to seek help and/or have someone looking out for them; or taking antipsychotic drugs and suffering psychomotor agitation, both of which can raise the body temperature.
Heat waves have also been said to be associated with an increase in suicide and suicide attempts. Page et al identified a 46.9% increase in suicide rates during the 1995 heat wave, and a number of commentators have pointed to a rise in suicidal behaviours during the spring and summer. Salib and Gray, examining fatal self-harm in Cheshire, found rates of death from fatal self-harm to be positively related to fine, rather than extreme, weather, whilst Deisenhammer et al found a higher risk of committing suicide on ‘days with high temperatures, low relative humidity or a thunderstorm and on days following a thunderstorm’. Barker et al also suggested that thunderstorms were ‘likely to be associated with an increased number of parasuicides [attempted suicides that may be conceived of as ‘cries for help’]’.
explaining a summer/suicide link
How might we explain such patterns? Barker et al note the suggestion that suicidal behaviour may peak in spring and early summer due to the ‘discrepancy noticed by depressed persons viewing the external world bursting into life when their internal world is lifeless’. They also suggest – as Durkheim did in his 1897 book Suicide – that seasonal variations in suicide rates are due to levels of social interaction. Spring and summer, rather than proving a counter to the isolation of the winter months, bring with them increased socialising opportunities that may lead to more relationship problems. Others have put forward biological explanations: increased air ionisation that raises the levels of adrenaline and serotonin in the body may, argued F.G. Sulman in the 1970s (see Carney et al), lead to more cases of mania in spring and summer. In their study of mania in Galway, however, Carney et al emphasise social factors. As a large part of Galway’s population are farmers, they say, the ‘frequently wet and windy [weather] contributes substantially to their psychological disposition’. Thus, ‘a bright sunny day is very welcome. For some it induces euphoria’.
Studies such as those by Carney et al are ultimately cautious in making definitive links between weather conditions and mental health. As Barker et al (see above) note, several variables are likely to influence suicidality, meaning any strong conclusions would require a large sample – and getting a large sample from a wide geographical area means that you also begin to see different weather conditions. Pinpointing a single variable when many ‘biologic and behavioural variables … undergo a 12-month cycle’ (such as hormonal cycles) means, say Ajdacic-Gross et al, that seasonal patterns in such complex matters as suicidal behaviour should be interpreted extremely cautiously.
Further reading and external links
S. Tromp, Biometeorology. The Impact of the Weather and Climate on Humans and their Environment (London: Heyden, 1980).
NHS Choices, Suicide – Getting help. (Includes links to helplines and support groups)