The epidemiology of comorbid depressive and conduct disorders in early adolescence

Abstract

Background: Youth with both depressive disorders (DD) and conduct disorders (CD) have more impairment and worse outcomes than those with either type of psychopathology alone, yet the literature on population burden, descriptive epidemiology and unique risk factors for this form of psychiatric comorbidity is scarce. Methods: Using diagnostic interview data on 521 public middle school students collected annually in 6th-8th grade we estimated the period prevalence of comorbid and non-comorbid DD and CD during early adolescence and examined the sociodemographic profiles of young adolescents (YAs) in each outcome group. We tested for associations between lifetime history of stressful life events (SLEs) and psychiatric diagnosis outcome group using multinomial logistic regression. Results: One-third of YAs manifested one or both types of disorder over the course of middle school and one in ten experienced both. Comorbid DD/CD occurred disproportionately among YAs from racial and ethnic minority groups and single-parent households. Comorbid YAs were 3.49 (95% CI: 1.69-7.23) times as likely to have accrued 5 or more SLEs prior to middle school compared to those with neither disorder during middle school, 2.95 (95% CI: 1.06-8.20) times as likely compared to those with a DD alone and 2.89 (95% CI: 1.21-6.89) times as likely compared to those with a CD alone. Conclusions: Traditional approaches underestimate the burden of comorbidity during early adolescence. Future research should seek to elucidate the mechanism whereby a high burden of childhood SLEs increases the risk of early-adolescent comorbidity, so as to inform intervention strategies.