Sunshine, temperature and suicidal behaviour in patients treated with antidepressants: an explorative nested...

Area of Science:

• Environmental Health
• Psychiatry
• Epidemiology

Background:

• Suicidal behavior is a significant public health concern, particularly among individuals initiating antidepressant treatment.
• Environmental factors such as sunshine and temperature are hypothesized to influence mood and behavior, but their specific role in suicidal behavior requires further investigation.

Purpose of the Study:

• To investigate the association between different exposure windows of sunshine and temperature and suicidal behavior in patients starting antidepressant treatment.
• To explore potential effect modification by age, sex, and season on these associations.

Main Methods:

• Conditional logistic regression analysis was employed using data from completed suicides (307) and suicide attempts (1674) as cases.
• Ten controls were matched to each case using risk-set sampling, controlling for potential confounders including season.
• Likelihood ratio tests and stratified analyses were used to examine the role of season, age, and sex, including interaction terms.

Main Results:

• No overall association was found between temperature or sunshine exposure and suicidal behavior across all patients.
• Age was identified as a significant effect modifier; older patients (65+) showed a potential increase in suicide and suicide attempt rates with higher temperature and sunshine exposure in unadjusted models.
• Specifically, in unadjusted analyses, increased daily temperature and sunshine in the preceding 4-8 weeks were associated with higher rates of suicide and suicide attempts in older adults, though these did not retain statistical significance in adjusted models.

Conclusions:

• While no overall link exists, age may modify the association between environmental factors and suicidal behavior.
• Findings suggest a potential increased risk for suicidal behavior associated with higher temperatures and sunshine in older adults, warranting further investigation in adjusted models.
• Further research is needed to confirm these age-specific associations and understand the underlying mechanisms.