Seasonal affective disorders among rural Finns and Lapps.

We investigated the prevalence of seasonal affective disorder (SAD) and subsyndromal SAD (S-SAD) in rural populations in south-western and northern Finland by using the Seasonal Pattern Assessment Questionnaire (SPAQ). A total of 1710 SPAQs were analysed. The prevalences of overall SAD and S-SAD were 12.0% and 27.1%, respectively. Winter SAD (W-SAD) was the most common type, with prevalences of 9.5% for W-SAD and 18.4% for W-S-SAD. The prevalences of overall and winter SAD did not differ between Finns living in northern and south-western Finland. Among the Lapps, W-SAD cases were less frequent than among the Finns in Lapland. Overall seasonality correlated significantly with female gender, high body mass index, high level of education and young age.