Psychological function is mildly impaired for prolonged periods before and after first unipolar major depressive episode.

Prognostic factors: Psychiatric data were obtained by Composite International Diagnostic Interview, as part of the Netherlands Mental Health Survey and Incidence Study (NEMSIS). Psychosocial function was assessed using the employment, partner, housekeeping, and leisure scales of the Groningen Social Disability Schedule. Between subject and within subject differences in disability were compared using Student’s t test. Retest and time effects were tested using ANOVA. Differences were expressed as effect sizes, which were calculated by dividing the mean difference in disability by the standard deviation of disability in the two groups.