In theory, the mood-regulating chemical serotonin could hold a role for the suicide rates. Previously there have been studies based on seasonal patterns, attempting to link them to suicide rates, but they contained counter-intuitive patterns. Even if winter is commonly associated with depressions and increased suicide rates, suicides peak in spring.
Because of this, the research team sought to find if sunlight could be related to suicide rates. By looking at 69,462 confirmed suicide records in Australia, between 1970 and 2010, they used meteorological stations to study daily sun hours during the 40-year period.
After conducting this study, two patterns came forth. The author states that in 10 days or less increased suicide rates were linked with a higher frequency of sunshine. But after two weeks to two months, they became linked with lower suicide rates. Furthermore, the team discovered that by analyzing what they found more, this short-term suicide risk increase was primarily found among women. Coincidentally, the long-term decrease of suicide rates was among men.
According to Dr. John Mann, a professor of translational neuroscience at Columbia University Medical Center in NY, the results should be interpreted cautiously. What factors into suicide is incredibly complicated, and so finding a fraction of the reasons adding to the resulting suicide is very difficult, according to Mann, uninvolved with the study.
One more researcher stated that the findings, “…add to growing evidence of the importance of light in brain health.” Exposure to bright light and sunlight have long been associated with increased levels of serotonin in humans and animals, said Dr. Phyllis Zee. Zee works at the Center for Sleep and Circadian Biology at North-western University in Chicago.
According to Zee, making use of these factors is one way that might improve symptoms of depression. “Light therapy is a treatment for people with seasonal affective disorder – depression that strikes in the dark days of winter.”
As to why the suicide rates would fluctuate so much, the Austrian researchers speculate that serotonin transmissions in the brain are one part of the whole. The substance is involved with a lot of psychological behavior, including impulsive and depressive behavior. At first it could boost people’s motivation for getting out of suicidal thought patterns, but the same substance could lead to severe depressions for a short time span.
It’s important to note that the correlations that were found were vague due to the small effect it appears to have had on the suicide rates. Mann stated that, “The effect would be very small, if it’s there at all. I don’t think people should avoid the sun because of this study.”
(Photo courtesy of Dawn Ellner)