Exploring lag and duration effect of sunshine in triggering suicide

Area of Science:

• Environmental Psychology
• Public Health Research
• Epidemiology

Background:

• Sunshine is commonly associated with improved mood.
• However, suicide rates tend to peak during early summer months.
• This suggests a complex relationship between sunlight and suicidal behavior.

Purpose of the Study:

• To investigate the temporal relationship between solar radiance and suicide risk.
• To identify potential lag and duration effects of sunshine exposure on suicide triggering.
• To analyze Greek suicide and solar radiance data over a decade.

Main Methods:

• Logistic regression models were employed.
• Daily suicide and solar radiance data from Greece were analyzed for a 10-year period.
• The analysis focused on a nine-day timeframe preceding suicide events.

Main Results:

• Significant association found between solar radiance on the preceding day and increased suicide risk (OR=1.020).
• Average solar radiance over four preceding days also significantly increased suicide risk (OR=1.031).
• Gender differences observed: males require longer exposure, females have a 3-4 day lag; June suicide risk is 52-88% higher than December due to sunshine.

Conclusions:

• Sunshine's effect on suicide risk may involve a lag and duration mechanism within the nine days prior to the event.
• Hypothesized that sunshine acts as an antidepressant, initially improving motivation before mood, creating a transient increased suicide risk.
• Limitations include lack of individual data on mental disorders, alcohol, or suicide methods.