Background: Several studies have shown an association between smoking and major depressive disorder (MDD), but few have prospectively examined subjects who develop MDD after quitting smoking. This descriptive study evaluated the development of MDD after smoking cessation, as assessed by a structured clinical interview at both baseline and the end of treatment.
Method: Nondepressed participants (N = 114) in a trial investigating the effect of fluoxetine on smoking cessation were administered the Structured Clinical Interview for DSM-III-R at baseline and posttreatment to evaluate the impact of quitting smoking on the development of MDD. Depressive symptoms were additionally assessed with the Beck Depression Inventory and the Hamilton Rating Scale for Depression.
Results: At baseline, 32% of the subjects reported a history of MDD. Sixty-nine subjects completed the SCID at baseline and posttreatment. At posttreatment, 5 subjects (7%) met threshold criteria for MDD; none were taking the highest dose of fluoxetine (60 mg), 4 were taking 30 mg, and 1 was taking placebo. All 5 had a history of MDD; 3 were women. Four had a history of substance abuse and attained at least 3 consecutive biochemically verified weeks of smoking abstinence. Those who developed MDD after treatment scored significantly higher on measures of depressed mood at baseline than those who did not develop MDD after smoking-cessation treatment.
Conclusion: The results from this descriptive study suggest that a subset of smokers may be at risk for developing MDD after smoking cessation.