The long-term course of depressive disorders in the Lundby Study

Background. The Lundby Study is a longitudinal cohort study on a geographically defined population consisting of 3563 subjects. Information about episodes of different disorders was collected during field investigations in 1947, 1957, 1972 and in 1997. Interviews were carried out about current health and past episodes since the last investigation; for all subjects information was also collected from registers, case-notes and key informants. This paper describes the course and outcome of 344 subjects who had their first onset of depression during the follow-up. Method. In this study individuals who had experienced their first episode of depression were followed up. Their course was studied with regard to recurrence of depression related to duration of follow-up, transition to other psychiatric disorders including alcohol disorders, as well as incidence and risk factors of suicide. Results. Median age at first onset of depression was around 35 years for individuals followed up for 30-49 years. The recurrence rate was about 40% and varied from 17% to 76% depending on length of follow-up. Transition to diagnoses other than depression was registered in 21% of the total sample, alcohol disorders in 7% and bipolar disorder in 2%. Five per cent committed suicide; male gender and severity of depression were significant risk factors. Conclusion. The low rates of recurrence and suicide suggest a better prognosis for community samples than for in- and out-patient samples.