title: Seasonality of manic depressive illness in Canada.
abstract: OBJECTIVE
  The objective of the study was to determine if a seasonal pattern existed for hospital admissions of manic depressive illness to a Ontario provincial psychiatric hospital.
  
  
  METHODS
  Admission records were reviewed for the 75 year period of the study. In the analysis factors including: mood state on admission, gender and the influence of psychotropic medications were considered.
  
  
  RESULTS
  For mania and depression there was no statistically significant seasonal pattern of admissions. For mixed state admissions peaked in the summer.
  
  
  CONCLUSIONS
  The results of this study contradict the seasonal pattern traditionally reported in the literature. The limitations of this study, which include changes in diagnostic criteria over time and admission date not identical to onset of affective episode, need to be acknowledged.
authors.affiliation: Division of Society, Women and Health, Centre for Addiction and Mental Health, Toronto, ON, Canada.
authors.forename: D K
authors.initials: DK
authors.lastname: Whitney
authors.forename: V
authors.initials: V
authors.lastname: Sharma
authors.forename: K
authors.initials: K
authors.lastname: Kueneman
mesh_terms: D000328:Adult; D000342:Affective Symptoms / Q000453:epidemiology; D000368:Aged; D001714:Bipolar Disorder / Q000453:epidemiology*; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009864:Ontario / Q000453:epidemiology; D012621:Seasons; D012737:Sex Factors