The prevalence of seasonal affective disorder in The Netherlands: a prospective and retrospective study of seasonal mood variation in the general population.

BACKGROUND: The aim of the present study was to assess the prevalence of seasonal affective disorder (SAD) in The Netherlands. METHODS: The subjects (n = 5356), randomly selected from community registers, were given the Seasonal Pattern Assessment Questionnaire and the Centre for Epidemiological Studies Depression Scale over a period of 13 months. The response rate was 52.6%. RESULTS: Three percent of the respondents met the criteria for winter SAD, 0.1% for summer SAD. The criteria for subsyndromal SAD, a milder form of SAD, were met by 8.5%, 0.3% of whom showed a summer pattern. Younger women received a diagnosis of SAD more often than men or older women. CONCLUSIONS: SAD subjects were significantly more often unemployed or on sick leave than other subjects. Respondents who met winter SAD criteria were significantly more depressed than healthy subjects, in both winter and summer. Finally, month of completion had no influence on the number of subjects meeting the SAD criteria.