title: No changes in mood with the seasons: observations in 3000 chronic pain patients.
abstract: OBJECTIVE
  Seasonal affective disorder (SAD) and the theory of the effect of light on depression have gained some popularity in recent years. Research on epidemiology is largely based on retrospective measures asking explicitly for the experience of seasonal variations. Those measures have a low positive predictive value and do not enable us to distinguish between experience and belief.
  
  
  METHODS
  A consecutive sample of chronic pain patients filled out a depression questionnaire (CES-D) routinely as part of the diagnostic interview on becoming in-patients at a Pain Clinic in Mainz during a 5-year period.
  
  
  RESULTS
  No support for seasonality or light effects was found.
  
  
  CONCLUSIONS
  The effect of light on depression or seasonality may be smaller than expected in general. SAD as a true disorder is probably rare.
authors.affiliation: Department of Psychology, University of Mainz, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Hardt
authors.forename: H U
authors.initials: HU
authors.lastname: Gerbershagen
mesh_terms: D000339:Affect; D002908:Chronic Disease; D005260:Female; D006801:Humans; D008027:Light; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000523:psychology*; D010147:Pain Measurement; D011569:Psychiatric Status Rating Scales; D012189:Retrospective Studies; D016574:Seasonal Affective Disorder / Q000175:diagnosis* / Q000523:psychology; D012621:Seasons; D011795:Surveys and Questionnaires