Suicidal behaviours in vulnerable adolescents. Time trends and their correlates

Background: Suicide rates have increased over the past three decades, especially in young men. Depression, conduct disorder, crime and substance misuse have also increased. This study tested hypotheses on the possible links between the secular increase in the rates of these behaviours. Method: A data set on 6091 subjects aged 8-18 years (58.4% boys) referred to psychiatric services over a 21-year period (1970-1990) was used. A detailed analysis of a random sample of 80 case notes was conducted. Results: Suicidal behaviours increased significantly among pubertal male adolescents only (n=1313). In this sub-sample, substance misuse accounted for the increase over time. The rates of both suicidal behaviours and of substance misuse almost doubled between 1979 and 1990 in this patient group. The case note analysis showed that solvent and alcohol misuse had also increased over the study period. Moreover, among the subjects misusing substances, alcohol was the only substance with a strong and positive association with suicidal behaviours. Substance misuse pre-dated suicidal behaviours in most patients. Conclusions: A link has been found between the increase over time of suicidal behaviours in adolescent boys and a contemporaneous increase in substance misuse. The strength and direction of the association suggests that alcohol misuse is the causal factor.