Since the description of SAD the prevalence of this disorder has been of particular interest. The more so, because early studies, indicated the correctness of the on theoretical grounds - expected interaction between latitude and prevalence rate of SAD. More eleborate prevalence studies, mainly in the USA indeed showed a positive correlation between prevalence rate and latitude. In Europe, only few studies have appeared. Although the results of most of these studies are preliminary and research-methods and criteria vary across studies, tentative conclusions are that the prevalence rates in Europe are considerably lower than in the USA, but that there is a similar trend in the direction of an increase of prevalence at higher latitudes.8"10 In the present study, the prevalence of SAD in the Netherlands is investigated.