Treated incidence of mental disorders in a prepaid group practice setting.

We followed a cohort of 7,666 individuals enrolled continuously for five years in a prepaid group practice in Columbia, Maryland. Incidence rates of all diagnosed mental disorders were estimated at approximately 3.7 per cent, lower for adolescents and children (about 3 per cent), higher for adult males aged 20-49 (4.3 per cent), and highest for adult females (5.8 per cent). Diagnoses are primarily for acute mental disorders and show a tendency to recur at fairly high rates.