Mental disorders as risk factors for suicidal behavior in young people: A meta-analysis and systematic review of longitudinal studies

Background: Suicide is the second leading cause of death for young people. Objective: To assess mental disorders as risk factors for suicidal behaviour among adolescents and young adults including population-based longitudinal studies. Method: We conducted a systematic literature review. Bibliographic searches undertaken in five international databases and grey literature sources until January 2017 yielded a total of 26,883 potential papers. 1701 full-text articles were assessed for eligibility of which 1677 were excluded because they did not meet our eligibility criteria. Separate meta-analyses were conducted for each outcome (suicide death and suicide attempts). Odds ratio (OR) and 95% confidence intervals (95%CI) and beta coefficients and standard errors were calculated. Results: 24 studies were finally included involving 25,354 participants (12-26 years). The presence of any mental disorder was associated with higher risk of suicide death (OR = 10.83, 95% CI = 4.69-25.00) and suicide attempt (OR= 3.56; 95% CI 2.24-5.67). When considering suicidal attempt as the outcome, only affective disorders (OR = 1.54; 95% CI = 1.21-1.96) were significant. Finally, the results revealed that psychiatric comorbidity was a primary risk factor for suicide attempts. Limitations: Data were obtained from studies with heterogeneous diagnostic assessments of mental disorders. Nine case-control studies were included and some data were collected in students, not in general population. Conclusions: Mental disorders and comorbidity are strong predictors of suicide behaviour in young people. Detection and management of the affective disorders as well as their psychiatric comorbidity could be a crucial strategy to prevent suicidality in this age group.