Anthony J Levitt1, Michael H Boyle. 1. Department of Psychiatry, Department of Nutritional Sciences, Fellowship Program, University of Toronto, Sunnybrook and Women's College Health Sciences Centre, Toronto, Ontario. anthony.levitt@swchsc.on.ca
Abstract
BACKGROUND: This study sought to determine whether the prevalence of the seasonal subtype of major depression (SAD) in the community varied as a function of latitude. METHODS: Random telephone numbers were generated across 8 degrees of latitude (41.5 degrees N to 49.5 degrees N) for the province of Ontario. Eight strata of 1 degree each were sampled equally throughout a 12-month period. Using a validated and structured diagnostic interview, we interviewed by telephone respondents over 20 years of age who had lived in the region for 3 years or more. We evaluated patterns of symptom change across seasons to establish a diagnosis of SAD according to DSM-IV criteria. RESULTS: Of the 2078 households that were assessed for eligibility, 1605 (77%) completed the interview. The crude prevalence of lifetime SAD was 2.6% (95% CI, 1.9 to 3.5). There was no impact of latitude on prevalence of either major depression or the seasonal subtype across the 8 strata, although the global measure of the severity of seasonal change in mood was significantly negatively correlated with latitude. CONCLUSIONS: SAD is a common subtype of major depression in Ontario, but there is no evidence to support an increase in prevalence with increasing latitude.
BACKGROUND: This study sought to determine whether the prevalence of the seasonal subtype of major depression (SAD) in the community varied as a function of latitude. METHODS: Random telephone numbers were generated across 8 degrees of latitude (41.5 degrees N to 49.5 degrees N) for the province of Ontario. Eight strata of 1 degree each were sampled equally throughout a 12-month period. Using a validated and structured diagnostic interview, we interviewed by telephone respondents over 20 years of age who had lived in the region for 3 years or more. We evaluated patterns of symptom change across seasons to establish a diagnosis of SAD according to DSM-IV criteria. RESULTS: Of the 2078 households that were assessed for eligibility, 1605 (77%) completed the interview. The crude prevalence of lifetime SAD was 2.6% (95% CI, 1.9 to 3.5). There was no impact of latitude on prevalence of either major depression or the seasonal subtype across the 8 strata, although the global measure of the severity of seasonal change in mood was significantly negatively correlated with latitude. CONCLUSIONS:SAD is a common subtype of major depression in Ontario, but there is no evidence to support an increase in prevalence with increasing latitude.
Authors: J L Anderson; M A St Hilaire; R R Auger; C A Glod; S J Crow; A N Rivera; S M Fuentes Salgado; S J Pullen; T K Kaufman; A J Selby; D J Wolfe Journal: Chronobiol Int Date: 2016-08-05 Impact factor: 2.877
Authors: Scott A Laurenzo; Randy Kardon; Johannes Ledolter; Pieter Poolman; Ashley M Schumacher; James B Potash; Jan M Full; Olivia Rice; Anna Ketcham; Cole Starkey; Jess G Fiedorowicz Journal: Psychiatry Res Date: 2016-10-21 Impact factor: 3.222
Authors: Uttam K Raheja; Sarah H Stephens; Braxton D Mitchell; Kelly J Rohan; Dipika Vaswani; Theodora G Balis; Gagan V Nijjar; Aamar Sleemi; Toni I Pollin; Kathleen Ryan; Gloria M Reeves; Nancy Weitzel; Mary Morrissey; Hassaan Yousufi; Patricia Langenberg; Alan R Shuldiner; Teodor T Postolache Journal: J Affect Disord Date: 2012-11-17 Impact factor: 4.839
Authors: Scott B Patten; Jeanne V A Williams; Dina H Lavorato; Jian Li Wang; Andrew G M Bulloch Journal: Can J Psychiatry Date: 2016-10-13 Impact factor: 4.356
Authors: Barbara Nussbaumer-Streit; Kylie Thaler; Andrea Chapman; Thomas Probst; Dietmar Winkler; Andreas Sönnichsen; Bradley N Gaynes; Gerald Gartlehner Journal: Cochrane Database Syst Rev Date: 2021-03-04