title: Quitting smoking does not increase the risk of major depressive episodes among users of Internet smoking cessation interventions.
abstract: BACKGROUND
  Limited evidence has suggested that quitting smoking increases the incidence of major depressive episodes (MDEs), particularly for smokers with a history of depression. Further evidence for this increase would have important implications for guiding smoking cessation.
  
  
  METHODS
  Spanish- and English-speaking smokers without a current MDE (n=3056) from an international, online smoking cessation trial were assessed for abstinence 1 month after their initial quit date and followed for a total of 12 months. Incidence of screened MDE was examined as a function of abstinence and depression history.
  
  
  RESULTS
  Continued smoking, not abstinence, predicted MDE screened at 1 month [smoking 11.5% v. abstinence 7.8%, odds ratio (OR) 1.36, 95% confidence interval (CI) 1.04-1.78, p=0.02] but not afterwards (smoking 11.1% v. abstinence 9.8%, OR 1.05, 95% CI 0.77-1.45, p=0.74). Depression history predicted MDE screened at 1 month (history 17.1% v. no history 8.6%, OR 1.71, 95% CI 1.29-2.27, p<0.001) and afterwards (history 21.7% v. no history 8.3%, OR 3.87, 95% CI 2.25-6.65, p<0.001), although the interaction between history and abstinence did not.
  
  
  CONCLUSIONS
  Quitting smoking was not associated with increased MDE, even for smokers with a history of depression, although a history of depression was. Instead, not quitting was associated with increased MDE shortly following a quit attempt. Results from this online, large, international sample of smokers converge with similar findings from smaller, clinic-based samples, suggesting that in general, quitting smoking does not increase the incidence of MDEs.
authors.affiliation: Department of Psychiatry, University of California, San Francisco, CA, USA.
authors.forename: L D
authors.initials: LD
authors.lastname: Torres
authors.forename: A Z
authors.initials: AZ
authors.lastname: Barrera
authors.forename: K
authors.initials: K
authors.lastname: Delucchi
authors.forename: C
authors.initials: C
authors.lastname: Penilla
authors.forename: E J
authors.initials: EJ
authors.lastname: Pérez-Stable
authors.forename: R F
authors.initials: RF
authors.lastname: Muñoz
mesh_terms: D000328:Adult; D015331:Cohort Studies; D003865:Major Depressive Disorder / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D038622:Internationality; D020407:Internet; D008297:Male; D016017:Odds Ratio; D011237:Predictive Value of Tests; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data; D012307:Risk Factors; D012657:Self-Help Groups; D016540:Smoking Cessation / Q000379:methods* / Q000523:psychology* / Q000706:statistics & numerical data