Autumn peak in shooting suicides of children and adolescents from northern Finland.

Suicide is one of the leading causes of death among adolescents worldwide. Studies on the seasonal pattern of youth suicides are rare and the results are very contradictory and heterogeneous. Generally, suicide methods affect the pattern of suicide seasonality. Shooting is the most common suicide method among Finnish adolescents. We investigated whether shooting suicides of victims aged less than 18 years are correlated with a specific period of the year. Also, the seasonal pattern of shooting suicides in adolescents was compared with that of adult victims. Our data comprised 42 adolescent suicide victims and, for comparison, 1,926 adult suicide victims over the years 1988 to 2004 from Northern Finland. Of these, 59.5% (n = 25) of the adolescents and 28.8% (n = 554) of the adults had committed suicide by shooting. We observed that shooting suicides among the under-aged showed a significant peak in autumn (ratio 2.70, 95% CI: 1.97-3.42), while those of adult victims peaked in spring (ratio 1.19, 95% CI: 1.05-1.35). The monthly pattern of suicides correlated significantly with the mean duration of daily sunshine hours (trailing by 3 months) in the under-aged (r = 0.67, p = 0.016), but not in the adults (r = 0.06, p = 0.854). The role of firearm availability, psychosocial factors such as start of the school year, and some biological factors are discussed.