Suicide Rates and Sunny Days Share a Complex Relationship

Contrary to popular belief, suicide rates peak during sunny days.

Scientists have stated in the past that there is a paradoxical relationship between suicide and seasons; More suicides are witnessed during Spring than winter.

The latest study has shown that sunshine is an independent risk factor for suicides. It was conducted by researchers at the Medical University Vienna and colleagues and was based on data on 69,462 officially confirmed suicides in Austria between January 1970 and May 2010. The team calculated hours of sunshine using data from 86 representative meteorological stations, according to a news release.

The scientists found that short-term sunshine exposure, say around ten days, was positively associated with suicide risk. However, sunshine exposure for 10 to 60 days protected people from suicide risk. The study shows that sunlight has a complex relationship with suicide rates.

Suicide is a multifaceted problem. The researchers say that one possible explanation for high suicide rates during sunny days is that light affects the serotonin systems in brain. Serotonin is associated with impulsive behavior, meaning that short-term exposure to sunshine can remove inhibitions, but don't improve mood and can actually motivate people to commit suicide.

"If you have enhanced energy and motivation and drive but your mood is still very depressed, that might favor a state where you are at greater risk for suicide," said Dr. Matthäus Willeit of the Medical University Vienna, according to The Time.

In the long-run, however, sunlight improves mood and prevents people from killing themselves.

"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," researchers wrote.

The study is published in the journal JAMA Psychiatry.