Depression and insomnia among adolescents: a prospective perspective

No studies of adolescents have examined the prospective, reciprocal association between insomnia and major depression.

A two-wave, community-based cohort of 3134 youths aged 11-17 at baseline. Major depression was assessed using DSM-IV criteria. Three measures of insomnia were used also following DSM-IV: P1, any symptom of insomnia; P2, any symptom plus impairment; P3, P2 with no comorbid mood, anxiety or substance use disorders.

In general, the association between insomnia and depression was stronger and more consistent for major depression than for symptoms of depression. Baseline insomnia (P1 and P2) increased subsequent risk of major depression 2-3-fold and P1 2-fold in multivariate analyses. Major depression increased risk for subsequent insomnia 2-3-fold for P1 and P2 2-fold for P2 in multivariate analyses. Results varied by measure of insomnia used.

Only symptoms of insomnia were assessed, so we could not examine the effects of comorbid sleep disorders nor did we have objective or biological measures of disturbed sleep. We also did not collect data on parental reports of youth depression nor insomnia or sleep problems.

Our results provide the first prospective data on insomnia and major depression among adolescents indicating the two are reciprocally related. More studies are needed examining trajectories of insomnia and major depression in childhood and adolescence.