 The research was a treatment-matching study to test whether adding fluoxetine pharmacotherapy to behavioral cessation treatment improved the depression-prone smokers ability to quit. The investigators randomized 144 smokers with a prior history of depression and 206 smokers who lack such a history to a double-blind treatment with either 60 mg fluoxetine or placebo, while they underwent cognitive behavioral treatment to quit smoking. The main study outcome was biologically verified abstinence 6 months after treatment. The administration of placebo and fluoxetine began 3 weeks before the quit smoke date and continued for 2 months post-quit date totaling 11 weeks on drugplacebo. Cognitive behavioral treatment were weekly before quitting and biweekly after quitting. There were monthly follow-up evaluations for six months after the quit date. The research tested both the Selective Benefit Hypothesis and the Generalized Benefit Hypothesis of fluoxetines effects. The hypothesis of the mechanism of action was that the drug diminished compulsive smoking behavior, obsessional cigarette craving, and nicotine withdrawal dysphoria that occurred independently of depressive vulnerability. 