title: Tobacco smoking as a risk factor for major depressive disorder: population-based study.
abstract: BACKGROUND
  Smoking is disproportionately prevalent among people with psychiatric illness.
  
  
  OBJECTIVE
  To investigate smoking as a risk factor for major depressive disorder.
  
  
  METHODS
  A population-based sample of women was studied using case-control and retrospective cohort study designs. Exposure to smoking was self-reported, and major depressive disorder diagnosed using the Structured Clinical Interview for DSM-IV-TR (SCID-I/NP).
  
  
  RESULTS
  Among 165 people with major depressive disorder and 806 controls, smoking was associated with increased odds for major depressive disorder (age-adjusted odds ratio (OR)=1.46, 95% CI 1.03-2.07). Compared with non-smokers, odds for major depressive disorder more than doubled for heavy smokers (>20 cigarettes/day). Among 671 women with no history of major depressive disorder at baseline, 13 of 87 smokers and 38 of 584 non-smokers developed de novo major depressive disorder during a decade of follow-up. Smoking increased major depressive disorder risk by 93% (hazard ratio (HR)=1.93, 95% CI 1.02-3.69); this was not explained by physical activity or alcohol consumption.
  
  
  CONCLUSIONS
  Evidence from cross-sectional and longitudinal data suggests that smoking increases the risk of major depressive disorder in women.
authors.affiliation: Department of Clinical and Biomedical Sciences: Barwon Health, The University of Melbourne, PO Box 281, Geelong 3220, Australia. juliep@barwonhealth.org.au
authors.forename: Julie A
authors.initials: JA
authors.lastname: Pasco
authors.forename: Lana J
authors.initials: LJ
authors.lastname: Williams
authors.forename: Felice N
authors.initials: FN
authors.lastname: Jacka
authors.forename: Felicity
authors.initials: F
authors.lastname: Ng
authors.forename: Margaret J
authors.initials: MJ
authors.lastname: Henry
authors.forename: Geoffrey C
authors.initials: GC
authors.lastname: Nicholson
authors.forename: Mark A
authors.initials: MA
authors.lastname: Kotowicz
authors.forename: Michael
authors.initials: M
authors.lastname: Berk
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D015331:Cohort Studies; D003866:Depressive Disorder / Q000209:etiology*; D005260:Female; D006801:Humans; D008019:Life Style; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D012907:Smoking / Q000523:psychology*; D055815:Young Adult