Natural course of adolescent major depressive disorder: I. Continuity into young adulthood.

OBJECTIVE: 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.
METHOD: 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.
RESULTS: 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.
CONCLUSIONS: This study documents the significant continuity of MDD from adolescence to young adulthood. Public health implications of the findings are discussed.