Physical dependence on nicotine in gum. A placebo substitution trial

To test whether ex-smokers become physically dependent on nicotine in gum, we entered eight ex-smokers who were using nicotine gum into a randomized, double-blind, placebo-substitution trial. When placebo was substituted, seven of the eight subjects were observed to have withdrawal symptoms and two relapsed to smoking or nicotine gum. This result suggests that physical dependence (ie, withdrawal) may be a cause of behavioral dependence on nicotine gum (ie, use of gum beyond the recommended period) and physicians should emphasize the need for gradual reduction of nicotine gum.