Background. This article presents prospective longitudinal findings on prevalence, incidence,
patterns of change and stability of depressive disorders in a community sample of 1228 adolescents.
Methods. Data were collected at baseline and follow-up (20 months later) in a representative
population sample of 1228 adolescents, aged 14–17 at baseline. Diagnostic assessment was based on
the Munich Composite International Diagnostic Interview (M-CIDI).
Results. The overall cumulative lifetime incidence of any depressive condition was 20·0% (major
depressive disorder (MDD), 12·2%; dysthymia, 3·5%; subthreshold MDD, 6·3%), of which about
one-third were incident depressions in the period between baseline and follow-up. Depressive
disorders rarely started before the age of 13. Females were about twice as likely as males to develop
a depressive disorder. Overall, the 20-month outcome of baseline depression was unfavourable.
Dysthymia had the poorest outcome of all, with a complete remission rate of only 33% versus 43%
for MDD and 54% for subthreshold MDD. Dysthymia also had the highest number of depressive
episodes, and most psychosocial impairment and suicidal behavioural during follow-up. Treatment
rates were low (8–23%). Subthreshold MDD associated with considerable impairment had an
almost identical course and outcome as threshold MDD.
Conclusions. DSM-IV MDD and dysthymia are rare before the age of 13, but frequent during
adolescence, with an estimated lifetime cumulative incidence of 14%. Only a minority of these
disorders in adolescence is treated, and more than half of them persist or remit only partly.