Minor depression as a predictor of the first onset of major depressive disorder over a 15‐year follow‐up

OBJECTIVE: To study the relationship of minor depression to first onset of major depressive disorder (MDD) among 1634 individuals over a 15-year follow-up using the Baltimore Epidemiologic Catchment Area cohort. METHOD: Logistic regression analyses were conducted with minor depression alone and also adjusting for anxiety, sociodemographic, and medical variables, with MDD as the outcome variable. Also, among those with minor depression, depressive symptom categories were studied with both logistic regression and population attributable risk (PAR) to determine if they predicted MDD. RESULTS: Individuals with a history of minor depression had an odds ratio of more than 5 of having a first lifetime episode of MDD (adjusted OR: 5.37, 95% CI: 2.87, 10.06). Suicidal ideation, appetite/weight issues, and sleep difficulty had the highest PARs. CONCLUSION: Minor depression strongly predicts MDD. Clinical and public health interventions for individuals with minor depression can potentially impact the pathway leading to MDD.