A new study from the Abramson Cancer Center and Department of Psychiatry in the University of Pennsylvania School of Medicine shows that smokers who carry a particular version of a gene for an enzyme that regulates dopamine in the brain may suffer from concentration problems and other cognitive deficits when abstaining from nicotine - a problem that puts them at risk for relapse during attempts to quit smoking.
The findings, newly published in the journal Molecular Psychiatry, pave the way to identify novel medications to treat nicotine addiction.
"These findings also provide an important step toward personalized therapy for nicotine addiction by clarifying the role of inherited genetic variation in smoking abstinence symptoms that promote relapse," says senior author Caryn Lerman, PhD, the Mary W. Calkins Professor in Penn's Department of Psychiatry and Scientific Director of Penn's Abramson Cancer Center.
"The new data identify a novel brain-behavior mechanism that plays a role in nicotine dependence and relapse during quitting attempts," says lead author James Loughead, PhD, assistant professor in the Department of Psychiatry. Loughead and Lerman studied groups of smokers with different inherited variations in a gene which influences levels of dopamine in the prefrontal cortex, the part of the brain that governs working memory and complex decision-making. Spurred by their previous findings that carriers of the catechol-O-methyltransferase (COMT) val gene variant are more susceptible to smoking relapse, the Penn researchers set out to learn if smokers with this genetic background would be more likely to exhibit altered brain function and cognitive deficits during periods of abstinence from smoking.
"Inability to concentrate after quitting is reported by many patients, and this leads them to smoke to reduce these impairments," Loughead says.