Context:There are no studies of the natural history of major depressive disorder that lack prevalence and clinic biases.Objectives: To estimate risk factors for first lifetime onset and parameters of chronicity following the first episode, including duration, recovery, and recurrence, and to search for predictors of each parameter.Design: Prospective population-based cohort study with 23 years of follow-up.Setting: East

Population-Based Study of First Onset and Chronicity in Major Depressive Disorder