The risk of suicide increases during a full moon, according to a paper published by psychiatrists from the Indiana University School of Medicine. The research team led by Alexander Niculescu, MD, PhD, examined the data on suicides from Marion County coroner’s office and collated the information with lunar phases.
“We wanted to analyze the hypothesis that suicides are increased during the period around full moons and determine if high-risk patients should be followed more closely during those times,” Niculescu said.
The analysis showed that the suicide rate significantly increased during the week of full moon, with people over age 55 being most affected. In addition, people are most likely to commit suicide in September and between 3-4 p.m.
However, scientists did not merely find some weird correlations, they offered a plausible explanation of this phenomenon, attributing it to the concept of circadian rhythms – our inner biological clock. These rhythms are connected to ambient light, which is why we prefer to sleep when it is dark.
The full moon produces more light than in any other phase, and it happens when there should be little-to-no light at all. This creates additional stress, which is why a person under any type of stress or pressure may decide to commit suicide. However, researchers have emphasized that this compelling hypothesis must be carefully evaluated and double-checked.
“The effect of ambient light and body clocks in suicide needs to be studied more closely, along with how people sleep and their exposure to light… Changes in light can affect vulnerable people, in conjunction with other risk factors,” Niculescu stated.
The explanation for the increase in suicide rates in the month of September and between 3-4 p.m. is vaguer and scientists do not have straightforward answers. They allege that this may be connected to intraday stress, stress due to the end of the vacation season in the summer, seasonal mental disorders and multiple other reasons.
“Our work shows the full moon, fall season and late afternoon are temporal windows of increased risk for suicide, particularly in individuals who suffer from depression or alcohol use disorders,” Niculescu added, as he expressed hope to examine in the future whether exposure to screens at night increases suicidal tendencies in people.