Parkinson's Drug May Help People Quit Smoking, Yale Study Shows
A drug used to treat Parkinson’s disease, selegiline hydrochloride, also appears to help smokers quit smoking, according to a study at Yale.
The study, published in the January 15 issue of the journal Biological Psychiatry, was conducted by Tony George, M.D., assistant professor of psychiatry at Yale School of Medicine. It is part of work being done through the Center for Nicotine and Tobacco Use Research and the Transdisciplinary Tobacco Use Research Center (CENTURY/TTURC).
The smokers in the study were all people who had tried to quit smoking numerous times and failed. One of the major themes of CENTURY/TTURC is finding solutions for smokers who find it particularly hard to quit.
“We specifically selected difficult-to-treat smokers because this is the group that hasn’t responded to conventional treatments,” said George. “While there are several effective treatments for smoking cessation, including nicotine replacement therapies and bupropion (Zyban), there are many smokers who do not respond to these drugs. So developing new drugs for smoking cessation is an important undertaking. Selegiline (Deprenyl(tm)) appears to be a drug that might have promise for treatment of nicotine addiction.”
Stephanie O’Malley, M.D., professor of psychiatry at Yale School of Medicine and CENTURY/TTURC’s principal investigator, said, “Dr. George’s study is an important contribution to our understanding of the subgroups of people who are not responsive to current treatments.”
George’s goal was to evaluate selegiline hydrochloride, a monoamine oxidase B (MAO-B) inhibitor, compared to placebo, for the treatment of nicotine dependence in smokers. Inhibition of MAO-B in the brain leads to increases in brain dopamine.
Selegiline is used to treat Parkinson’s disease, a neurological disorder associated with dopamine deficiency. A component of cigarette smoke, not nicotine, is known to inhibit brain monoamine oxidase activity in smokers, which was one of the reasons George undertook the study.
The results from George’s pilot study are extremely promising. Smoking abstinence rates were significantly higher in the group taking selegiline compared to those taking a placebo. Interestingly, smokers with clinically significant depressive symptoms at the beginning of the study had poorer smoking cessation outcomes compared to those who did not have significant depression.
“This is yet another example of how having co-morbid psychiatric symptoms contributes to poorer smoking cessation outcomes,” George said. He runs the Program for Research in Smokers with Mental Illness, which focuses on understanding how smoking is linked to psychiatric disorders. This is also a major focus of the CENTURY group.
George’s study was one of three initial pilot studies for the CENTURY/TTURC group. The Yale TTURC, which is part of CENTURY, receives funding from the National Institute on Drug Abuse, the National Cancer Institute and the Robert Wood Johnson Foundation.
Other investigators on the study included Jennifer Vessicchio, research associate; Angelo Termine, research associate; Peter Jatlow, M.D., professor and chair, Department of Laboratory Medicine and professor of psychiatry; Thomas Kosten, M.D., professor of psychiatry, and Stephanie O’Malley, professor of psychiatry.