A cohort of 158 patients was identified from 723 patients admitted in 1990 or treated as outpatients in 1991 for affective disorders in three university hospitals in Copenhagen, covering a well-defined catchment area. The cohort was subclassified for seasonal pattern according to DSM-III-R. Meteorological data of temperature, hours of sunshine, rainfall and wind-velocity expressed as mean values/month were obtained from the Institute of Meteorology in Copenhagen. There was no relationship between the annual dis- tribution of affective episodes and meteorological data, neither in the total cohort nor in the subgroup of patients with seasonal patterns The present study does not support the hypothesis that a relation exists between start of a new episode and the season or climatic condition.
