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There are smokers who carry a particular version of a gene for an enzyme that can regulate dopamine in the brain, that’s why they can suffer from concentration problems and other cognitive deficits when they abstain from nicotine.

This is a problem that puts them at risk for relapse during attempts to quit smoking. Even dopamine can be supplied as a medication that acts on the sympathetic nervous system, producing effects such as increased heart rate and blood pressure, this problem remains unsolved yet and people continue to suffer from nicotine addiction.

These are findings which 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. "The new data identify a novel brain-behavior mechanism that plays a role in nicotine dependence and relapse during quitting attempts," said James Loughead, PhD, assistant professor in the Department of Psychiatry.

Loughead and Lerman studied groups of smokers with different variations in a gene which influences levels of dopamine in the prefrontal cortex, the part of the brain that governs memory working. "Inability to concentrate after quitting is reported by many patients, and this leads them to smoke to reduce these worsening," Loughead added.

Scientists studied 33 smokers. They scanned their brain and asked them to hold in their minds a series of complex geometric figures. Smokers were also asked to complete a withdrawal symptoms checklist and a questionnaire about their smoking urges. Results showed that smokers with the catechol-O-methyltransferase (COMT) gene, suffered greater deficits in working memory and brain function when they had refrained from smoking for 14 or more hours, compared to their performance on this task when they had been smoking as usual. Scientists consider that the smokers, with such a gene, will have always abstinence from smoking.