Seasonality of suicide: a multi-country multi-community observational study

Area of Science:

• Epidemiology
• Public Health
• Environmental Psychology

Background:

• Seasonal variations in suicide rates are documented, but the extent of heterogeneity across diverse populations remains underexplored.
• Understanding these variations is crucial for developing effective, context-specific suicide prevention programs.

Purpose of the Study:

• To investigate the heterogeneity of seasonal suicide patterns across geographically, demographically, and socioeconomically diverse populations.
• To identify factors influencing these seasonal variations in suicide.

Main Methods:

• Analysis of weekly suicide count time-series data from 354 communities in 12 countries (1986-2016).
• Two-stage analysis: generalized linear models with cyclic splines for community-level patterns, followed by country-level meta-regression.
• Meta-regression was used to explore associations between seasonal patterns and community-level indicators (socioeconomic, demographic, environmental).

Main Results:

• Most countries exhibited spring suicide peaks and winter troughs, but pattern shapes (unimodal to bimodal) and amplitudes varied significantly.
• Amplitude differences were observed across genders and age groups (elderly vs. younger) and varied over time within countries.
• Larger seasonal amplitudes were associated with colder climates, higher proportions of elderly individuals, and lower unemployment rates.

Conclusions:

• Seasonal suicide patterns are highly heterogeneous, differing in shape, amplitude, subgroup effects, and temporal trends across populations.
• Climate, demographic, and socioeconomic conditions significantly influence these seasonal patterns.
• Findings support the development of tailored suicide prevention programs informed by specific population characteristics and seasonal trends.