Psychological and pharmacological influences in cigarette smoking withdrawal: effects of nicotine gum and expectancy on smoking withdrawal symptoms and relapse.

To determine the relative effects of expectancy and nicotine depletion on aversive withdrawal symptoms, we gave 109 smokers attempting to quit either nicotine gum or placebo within a balanced placebo design and monitored their withdrawal symptoms and smoking for 2 weeks. Subjects who believed they were getting nicotine gum reported less physical symptoms of withdrawal, showed less arousal, and smoked fewer cigarettes during the first week of quitting when compared with those who thought they were receiving placebo gum. The actual nicotine content of gum had no effect on withdrawal or relapse.