Bupropion facilitates dopamine transmission; thus, many clinicians preferentially use this agent for depressed patients with Parkinson's disease. The fact that dopamine is integrally related to the brain's reward mechanisms, which are stimulated by nicotine and other addictive substances, has provided the theoretical underpinning for recent research indicating that bupropion is an effective aid in smoking cessation. Placebo-controlled trials involving nondepressed, chronic cigarette smokers found a dose-dependent increase in the percentage of patients able to achieve abstinence. Individuals receiving 300 mg/day of bupropion were able to sustain abstinence longer than those receiving 150 mg/day, and results achieved by patients given bupropion were superior to those achieved in the placebo groups. Bupropion is being marketed under the name Zyban as a tool for smoking cessation (Zyban 2005).