Seasonal and weather factors in parasuicide
Barker A., Hawton K., Fagg J., Jennison C.
Background. Seasonal variation in suicide and parasuicide has previously been reported. Few investigations have examined whether meteorological factors could influence suicidal behaviour, and the inconclusive results produced may be due to a variety of methodological problems. The present study overcomes some previous difficulties and tested whether parasuicide admission rate is related to weather variables. Method. Over 12 000 admissions for parasuicide were analysed by month, season, and in relation to meteorological data, which were measured close to the admitting hospital. Results. Marked seasonal (P < 0.001) and monthly (P < 0.001) variations in mean daily parasuicide numbers were seen in women but not men. Small but highly significant correlations were demonstrated between parasuicide rate and weather parameters (P < 0.01), which were more marked in women (P < 0.01). These effects were additional to the monthly variation (P < 0.05). Conclusions. Weather has a small influence on parasuicide. Gender differences in body temperature regulation might account for the sex difference seen.