Sunshine linked to suicide risk

Is there any link between sunshine and suicide? Yes, say researchers.

According to researchers from the Medical University of Vienna, sunshine is indeed linked to fatal self-harm, independent of the season.

"The amount of light approximately two weeks before a suicide event is positively correlated with suicide. The more light you have in a certain period, probably short-ranging, the more likely is a person, who is already at risk, to commit suicide," explained Matthaeus Willeit, a professor at the Medical University of Vienna, Austria.

The study analysed if patients with severe episodes of depression are more susceptible to the suicide triggering effects of sunshine.

During the study, authors analyzed data on 69,462 officially confirmed suicides in Austria between January 1970 and May 2010.

Hours of sunshine per day were calculated from 86 meteorological stations.

There was a positive correlation between the number of suicides and hours of daily sunshine on the day of the suicide and up to 10 days before that.

Sunshine 14 to 60 days prior appeared to have a negative correlation and was associated with reduced suicides.

"The correlation between daily sunshine hours and suicide rates was seen largely among women, while negative correlations between the two were mainly found among men," Willeit noted.

Light interacts with brain serotonin system and possibly influences serotonin-related behaviours.

Those behaviours such as mood and impulsiveness can play a role in suicide, the study concluded.

The paper was published in Journal of the American Medical Association Society Psychiatry (JAMA Psychiatry).