title: Dates of birth and seasonal changes in well-being among 4904 subjects completing the seasonal pattern assessment questionnaire.
abstract: BACKGROUND
  Abnormal distributions of birthdates, suggesting intrauterine aetiological factors, have been found in several psychiatric disorders, including one study of out-patients with Seasonal Affective Disorder (S.A.D.). We investigated birthdate distribution in relation to seasonal changes in well-being among a cohort who had completed the Seasonal Pattern Assessment Questionnaire (SPAQ).
  
  
  METHODS
  A sample of 4904 subjects, aged 16 to 64, completed the SPAQ. 476 were cases of S.A.D. on the SPAQ and 580 were cases of sub-syndromal S.A.D. (S-S.A.D.). 92 were interview confirmed cases of S.A.D. Months and dates of birth were compared between S.A.D. cases and all others, between S.A.D. and S-S.A.D. cases combined and all others, and between interview confirmed cases and all others. Seasonality, as measured through seasonal fluctuations in well-being on the Global Seasonality Scores (GSS) of the SPAQ, was compared for all subjects by month and season of birth.
  
  
  RESULTS
  There was no evidence of an atypical pattern of birthdates for subjects fulfilling criteria for S.A.D., for the combined S.A.D./S-S.A.D. group or for interview confirmed cases. There was also no relationship between seasonality on the GSS and month or season of birth.
  
  
  CONCLUSIONS
  Diagnoses of S.A.D. made by SPAQ criteria are likely to be overinclusive.
  
  
  CONCLUSIONS
  Our findings differ from studies of patients with more severe mood disorders, including psychiatric out-patients with S.A.D. The lack of association between seasonality and birthdates in our study adds credence to the view that the aetiology of S.A.D. relates to separable factors predisposing to affective disorders and to seasonality.
authors: Royal Cornhill Hospital, Cornhill Road, Aberdeen, AB25 2ZH, UK. john.eagles@gpct.grampian.scot.nhs.uk
authors: John M
authors: JM
authors: Eagles
authors: Neil W
authors: NW
authors: Scott
authors: Isobel M
authors: IM
authors: Cameron
authors: Samantha M
authors: SM
authors: Wileman
authors: Simon A
authors: SA
authors: Naji
mesh_terms: D000293:Adolescent; D000328:Adult; D001723:Birth Rate; D003866:Depressive Disorder / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D016574:Seasonal Affective Disorder / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology*; D011795:Surveys and Questionnaires