To evaluate the potential impact of early childhood problems on the chronicity of mood disorders. A representative cohort from the population was prospectively studied from ages 19/20 to 39/40. Unipolar (UP) and bipolar disorders (BP) were operationally defined applying broad Zurich criteria for bipolarity. Chronicity required the presence of symptoms for more days than not over 2 years prior to an interview, or almost daily occurrence for 1 year. A family history and a history of childhood problems were taken at ages 27/28 and 29/30. Data include the first of multiple self-assessments with the Symptom-Checklist-90 R at age 19/20, and mastery and self-esteem assessed 1 year later. A factor analysis of childhood problems yielded two factors: family problems and conduct problems. Sexual trauma, which did not load on either factor, and conduct problems were unrelated to chronicity of UP or BP or both together. In contrast, childhood family problems increased the risk of chronicity by a factor of 1.7. An anxious personality in childhood and low self-esteem and mastery in early adulthood were also associated with chronicity. Childhood family problems are strong risk factors for the chronicity of mood disorders (UP and BP). The risk may be mediated partly by anxious personality traits, poor coping and low self-esteem.