Lack Of Sunlight Linked To Rise In Suicides

Japanese researchers have discovered an increase in railway suicide attempts following several consecutive days without direct sunlight.

Asian Scientist (Oct. 3, 2013) – Japanese researchers have discovered a pattern of increased railway suicide attempts following periods of little or no sunlight, especially after several consecutive rainy or cloudy days when there is no direct sunlight.

Although psychiatrists, epidemiologists, and sociologists have long debated whether suicide incidence is linked to weather conditions, there had been no evidence showing that such an association exists.

In this study, published in the Journal of Affective Disorders, the researchers looked at the amount of sunlight preceding 971 railway suicides attempts between 2002 and 2006 in Japan and found that suicide attempts increased on days that were preceded by at least three days without direct sunlight.

The data, taken from Tokyo, Kanagawa, and Osaka, also showed that the hours of sunlight on the day of the suicide attempt were not associated with more attempts. According to the researchers, this suggests that railway suicide attempts in these areas are associated with recent, but not current, weather conditions.

However, the researchers believe that it is the amount of sunlight, rather than the poor weather that led to the increase in suicide incidence.

“Rather than the weather of the day of suicides, having not been exposed to sunlight during the preceding days may have a greater influence on the symptoms of depression and decline in mood,” said Professor Hiroshi Kadotani, the lead author of the study, according to a Xinhua News Agency report.

The researchers suggest that measures should be taken during periods of reduced sunlight to prevent railway suicide attempts. These include increased patrols at train stations and railroad crossings and installing high-intensity white light bulbs designed for treating depression at train station platforms and train cars.

The article can be found at: Kadotani et al. (2013) Railway Suicide Attempts Are Associated With Amount Of Sunlight In Recent Days.


Copyright: Asian Scientist Magazine; Photo: kalleboo/Flickr/CC.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.

Yew Chung is a postdoctoral research fellow at the Duke-NUS Graduate Medical School, Singapore.

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