Seasonality, suicidality and melatonin.

Seasonality of suicidal behavior has been investigated regarding both neurobiological and climatic factors, as well as psychopathological and social aspects. Most of the studies detectedpeaks in late spring and troughs in the winter. Several lines of evidence evaluated the role of extended periods of light associated with probability of suicides whereas others summarize the alterations of melatonin excretion and its seasonal variation along with seasonaldistribution of psychiatric disorders. The purpose of this paper is to provide an overview of studies attempted to reach an explanatory model of underlying pathophysiology of melatonin in thepathogenesis of seasonal variation in suicidality. There is argument on the interconnection between suicide rates and weather factors. However, an inverse pattern of melatonin levels and the seasonalpeak in suicides was observed. These findings suggest that sunlight exposure along with a wide spectrum of other factors may explain the aetiopathogenesis of suicidal behavior.