Saturday, May 11, 2013

Are suicides seasonal?

Deaths due to suicide are quite a significant social problem, especially in developing countries where incomes are low. The WHO estimates that 877700 persons worldwide (that's a huge number) committed suicide in 2002. The main factors that emerge as significant in suicide statistics are gender, age, religion, marital status, as well as - obviously - physical and mental health. 

However, research suggests that suicides are also seasonal to some extent. Suicide rates seem to peak in summer, coinciding with the summer peak for mental disorders. Surprisingly, this seasonality is only visible in some countries and not in others. Studies have shown that suicide rates peak in summer in Finland, Ireland and Italy, but this pattern was much less visible or even absent in studies conducted in England and Wales, Australia and New Zealand, Singapore and Switzerland. It has been postulated that in Western countries, the seasonality of suicide is diminishing and may eventually disappear.

The methods chosen for suicide may also follow seasonal patterns, at least in some parts of the world. A study done in Iran showed that between 2006 and 2010, more than twice as many men as women committed suicide and that the frequency of suicide among men was higher in winter. Furthermore, this study showed that self-immolation (setting oneself on fire) occurred significantly less often in autumn as compared to other seasons, while poisoning was less frequent in winter. However, the highest number of completed suicides took place in the warm months - June and July. This study analyzed a total of 15822 completed suicides, out of which 70.5% were men and 29.5% were women.

According to the literature, it isn't possible to identify a specific weather condition associated with a generally higher risk for suicide. Many different studies have showed statistically significant correlations between different weather conditions and suicide frequency. For example, Austrian researchers have reported in 2003 that the risk of committing suicide in Tyrol was significantly higher on days with high temperatures, low relative humidity or a thunderstorm and on days following a thunderstorm. Weather and seasonal effects may interact with each other.

All this may not be very bizarre, but it's certainly interesting. I always thought that the dark winter months are toughest for people suffering from depression and this gets reflected in suicide rates. Well, it turns out that hot summers and thunderstorms might be more dangerous when it comes to upsetting susceptible individuals.

 Image from: Wikipedia

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