Changes in the seasonality of suicides over time in Slovenia, 1971 to 2002

BACKGROUND: Recent studies have reported changes in the time patterns of suicide, with reduced seasonality in some European and Asian countries. Anyway conflicting data were reported on the fading of suicide seasonality, and in some countries a rising trend was reported. METHODS: Harmonic spectral analysis was used to analyze all suicides in Slovenia in the years 1971 to 2002 (14,325 among males; 4350 among females). Analyses of overall changes are based on data aggregated by intervals of 8 years. RESULTS: In both sexes, seasonal variance accounts for a statistically significant proportion of total variance (36.0% among males; 13.3% among females). Anyway in both sexes the season-attributable variance in the latest interval is considerably lower than in the preceding periods. LIMITATIONS: Data could not be analyzed according to age or to mental disorder diagnosis, since this information was not available. CONCLUSION: The seasonal effect on mortality by suicide is sensitive to change, but its causes seem not to be sex-dependant.