Effects of treatment for tobacco dependence on resting cerebral glucose metabolism.

While bupropion HCl and practical group counseling (PGC) are commonly used treatments for tobacco dependence, the effects of these treatments on brain function are not well established. For this study, 54 tobacco-dependent cigarette smokers underwent resting (18)F-fluorodeoxyglucose-positron emission tomography (FDG-PET) scanning before and after 8 weeks of treatment with bupropion HCl, PGC, or pill placebo. Using Statistical Parametric Mapping (SPM 2), changes in cerebral glucose metabolism from before to after treatment were compared between treatment groups and correlations were determined between amount of daily cigarette usage and cerebral glucose metabolism. Compared with placebo, the two active treatments (bupropion HCl and PGC) had reductions in glucose metabolism in the posterior cingulate gyrus. Further analysis suggested that PGC had a greater effect than bupropion HCl on glucose metabolism in this region. We also found positive correlations between daily cigarette use and glucose metabolism in the left occipital gyrus and parietal-temporal junction. There were no significant negative correlations between daily cigarette use and glucose metabolism. Our findings suggest that bupropion HCl and PGC reduce neural activity much as the performance of a goal-oriented task does in the default mode network of the brain, including the posterior cingulate gyrus. Thus, this study supports the theory that active treatments for tobacco dependence move the brain into a more goal-oriented state.