title: Seasonal affective disorder and latitude of living.
abstract: OBJECTIVE
  Since the importance of latitude of living for the prevalence of Seasonal Affective Disorder (SAD) is unclear, the study aims to test the latitude hypothesis by comparing SAD in two rather similar groups of students living at latitudes far apart.
  
  
  METHODS
  Two groups of students, 199 in Tromsø, Norway (690 N) and 188 in Ferrara, Italy (440 N) were asked to fill in the Seasonal Pattern Assessment Questionnaire.
  
  
  RESULTS
  Global Seasonality score (GS-score) was significantly higher in Italian than in Norwegian students, in females and in students with sleeping-problems. Norwegian students had significantly higher SAD prevalence in winter and in spring. Most people in both countries felt worst in October and November, and the prevalence of Autumn SAD was not significantly different between the two countries.
  
  
  CONCLUSIONS
  The hypothesis that SAD is linked to amount of environmental light and latitude of living was not supported.
authors.affiliation: Department of Clinical Psychiatry, Institute of Clinical Medicine, Faculty of Medicine, University of Tromsø, and Psychiatric Department, University Hospital North, Norway.
authors.forename: Greta
authors.initials: G
authors.lastname: Brancaleoni
authors.forename: Elena
authors.initials: E
authors.lastname: Nikitenkova
authors.forename: Luigi
authors.initials: L
authors.lastname: Grassi
authors.forename: Vidje
authors.initials: V
authors.lastname: Hansen
mesh_terms: D005260:Female; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D009664:Norway / Q000453:epidemiology; D016574:Seasonal Affective Disorder / Q000453:epidemiology*; D055815:Young Adult