Direct effect of sunshine on suicide

Area of Science:

• Environmental Psychology
• Public Health
• Meteorology

Background:

• Suicidal behavior exhibits seasonal patterns, potentially influenced by sunshine and other environmental factors.
• Seasonal variations in social behavior may also affect suicide rates.
• Previous research suggests a link between sunshine and suicide, but isolating this effect from seasonal influences is challenging.

Purpose of the Study:

• To determine the impact of sunshine duration on suicide incidence, independent of seasonal variations.
• To analyze the correlation between daily sunshine hours and suicide occurrences.

Main Methods:

• Retrospective analysis of 69,462 confirmed suicides in Austria (1970-2010).
• Data on average daily sunshine duration from 86 meteorological stations.
• Statistical modeling using Pearson correlation coefficients after mathematically removing seasonal effects from both suicide and sunshine data.

Main Results:

• A significant positive correlation was found between daily sunshine and suicide on the day of and up to 10 days prior to the event (r=0.0370, P<10-5).
• A significant negative correlation was observed between daily sunshine and suicide rates 14 to 60 days before the event (r=-0.0383, P<10-5).
• These correlations were consistent across the entire sample and specifically for violent suicides.

Conclusions:

• Daily sunshine duration is significantly correlated with suicide frequency, independent of season, though effect sizes are small.
• Sunshine in the immediate period (0-10 days) before suicide may facilitate the act.
• Increased sunshine in the preceding weeks (14-60 days) appears to be associated with lower suicide rates, suggesting a potential protective effect.