Is liability to recurrent major depressive disorder present before first episode onset in adolescence or acquired after the initial episode?

Many individuals who experience a major depressive episode will subsequently develop recurrent episodes. Although numerous studies have investigated predictors of recurrent episodes, methodological limitations have made it difficult to determine the extent to which liability to recurrent major depressive disorder (rMDD) exists prior to first onset or develops after first onset. This study used a prospective design in a community sample of adolescents to examine variables before and after first onset MDD as predictors of rMDD over a 12-year follow-up. Among 59 adolescents who experienced first onset MDD, 72.88% developed rMDD during the follow-up period. Parental history of rMDD and lifetime history of minor depression prior to MDD onset significantly predicted rMDD. These two effects replicated in ancillary analyses in an expanded sample of N = 205. Following MDD onset, a higher number of major life events significantly predicted rMDD. Liability to rMDD exists prior to MDD onset in the form of familial risk and less severe mood disturbances, whereas liability to rMDD in the form of elevated stress may develop following a first onset in adolescence.