To examine the course of adolescent major depressive disorder (MDD) by comparing rates of mood and non-mood disorders between age 19 and 24 years in participants with a history of adolescent MDD versus participants with adolescent adjustment disorder with depressed mood, nonaffective disorder, and no disorder.

Participants from a large community sample who had been interviewed twice during adolescence completed a third interview assessing Axis I psychopathology and antisocial and borderline personality disorders after their 24th birthday: 261 participants with MDD, 73 with adjustment disorder, 133 with nonaffective disorder, and 272 with no disorder through age 18.

MDD in young adulthood was significantly more common in the adolescent MDD group than the nonaffective and no disorder groups (average annual rate of MDD = 9.0%, 5.6%, and 3.7%, respectively). Adolescents with MDD also had a high rate of nonaffective disorders in young adulthood (annual nonaffective disorder rate = 6.6%) but did not differ from adolescents with nonaffective disorder (7.2%). Prevalence rates of dysthymia and bipolar disorder were low (1%). Adolescents with adjustment disorder exhibited similar rates of MDD and nonaffective disorders in young adulthood as adolescents with MDD.

This study documents the significant continuity of MDD from adolescence to young adulthood. Public health implications of the findings are discussed. J. Am. Acad. Child Adolesc. Psychiatry, 1999, 38(1):56–63.