Study Links Duration of Sunlight Exposure to Suicide Cases

The amount of sunlight an individual is exposed to influences his/ her suicidal behavior, finds a study.

Morning sunlight exposure is known to increase people's happiness level and also cuts their risk of falling prey to a number of conditions like obesity and vitamin D deficiency. A new research examined the association between number of suicides and the amount of sunlight absorbed by people within the last 14 to 60 days of the attempt. Their trial used records of 69,462 officially confirmed suicide cases in Austria between 1970 and 2010. The amount of sunlight received in a day was based on the calculations of 86 weather stations.

The analysis revealed a direct positive- relation between the number of suicides and hours of sunlight absorbed on the same day or 10 days before the incident. But exposure to more amount of sunlight 14 to 60 days prior was associated with less number of suicide cases in the country. In addition, they found those who committed suicide on days when there was maximum sunshine were all women. Men mostly belonged to the group of suicide victims who received sunlight exposure more than two weeks before.

The research explained the human brain produces a hormone called serotonin in the presence of light. Higher exposure can alter the mood and emotions leading to suicidal ideation and behaviors.

"Owing to the correlative nature of the data, it is impossible to directly attribute the increase in suicide to sunshine during the 10 days prior to the suicide event. Further research is warranted to determine which patients with severe episodes of depression are more susceptible to the suicide-triggering effects of sunshine," the authors write in the study.

More information is available online in JAMA Psychiatry.