Scientists identify brain regions that may predict success rate for quitting smoking

Activity in the brain’s self-control center may predict the chance of relapse after an attempt to quit smoking, according to new research from Penn Medicine.

Using functional magnetic resonance imaging (fMRI), researchers studied the neural activity of 80 smokers seeking treatment. Participants were between ages 18 and 65, and reported smoking more than 10 cigarettes a day for more than six months.

Participants underwent two fMRI sessions: one immediately after smoking and another 24 hours after abstinence began. Researchers assessed the participants’ behavior seven days after they began trying to abstain from smoking.

“The vast majority of people who relapse [do so] within the first seven days,” Caryn Lerman, a professor of psychiatry at Penn Medicine, told “When we look at the original sample of 80 people, 19 of them were able to make it the entire seven days … that’s 75 percent who couldn’t make it.”

Lerman, the director of Penn's Center for Interdisciplinary Research on Nicotine Addiction, noted that most people attempting to quit do not make it 24 hours before resuming smoking.

According to the American Cancer Society, only 4 to 7 percent of people are able to quit smoking on any given attempt without medicines or other help. About 25 percent of smokers who use medicine can remain abstinent for over six months, and emotional support may boost success rates.

Using fMRI scans, researchers found that participants who showed a decrease in activity in the dorsolateral prefrontal cortex— the part of the brain central to cognitive function, working memory and goal-directed behavior— were the most likely to relapse. Those who relapsed also had increased activity in the posterior cingulate cortex— a region of the brain unrelated to goal achievement.

This activity is the opposite of what the brain needs for success, Lerman said.

“What we really want to have going on in the brain [for success] is a combination of increased activity planning, goal directiveness and cognitive control, and suppression in the part of the brain involved in rumination and thinking about self and non-goal-related thought,” she said.

While the cause of the brain’s changes after smoking aren’t definitively known, previous Penn Medicine research has shown that when people go off nicotine, there are decreases across brain regions involved in cognitive control and goal-directed thoughts, as well as poorer cognitive performance. Many complain that it’s harder to concentrate after quitting smoking, Lerman noted.

“[That’s] in part because nicotine increases activity to those parts of the brain and the brain is used to that,” she said. “When you stop, there’s no more nicotine to activate those brain regions, and you tend to have decreased activity in cognitive control and goal direction.”

“So stopping smoking itself makes it more difficult to stay off cigarettes— [it] compromises exactly those processes that you need to be successful,” Lerman said.

Current clinical and behavioral tools for predicting abstinence success are limited to self-reported measures, such as smoking history, dependence on nicotine, education level, and smoking frequency.

Heavier smokers and those with a higher level of dependence tend to have a higher risk of relapse, Lerman said, noting that there is a great variability in dependence and these measures do not have a high predictive value.

The researchers’ predictive model incorporated brain scan data, withdrawal symptoms, and demographic and smoking history, resulting in a 16 percent increased accuracy over a model using only demographic and smoking history.

These findings may be useful for creating new models of predictive tests and targeted treatments, the study authors said.

While Lerman said it would be impractical to do a brain scan on every smoker who wants to quit, she predicts that in the next five years, as technology evolves, there could be a battery of cognitive, brain imaging and genetic tests that will allow a high prediction value— allowing for customized treatment for better results.

Scientists are currently in the early stages of testing for approaches that target the prefrontal cortex.

“This provides another important piece of evidence … that this region in the prefrontal cortex is important in quitting smoking,” Lerman said. “So if we can apply treatments that will help increase activity in that part of the brain, [our research] suggests those new treatments will be successful in helping people quit.”

The research was published in Neuropsychopharmacology.