Smokers’ Brain Reward Systems Don’t Respond To Benefits Of Quitting Cigarettes

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It’s a question that many non-smokers constantly ask: Why do smokers continue to smoke knowing that it’s not only harmful, but that they’re also wasting their money? A new study from Penn State University may have found why it’s harder for some people to quit — it essentially comes down to their brains’ chemistry, and willpower.

“We believe that our findings may help to explain why some smokers find it so difficult to quit smoking,” said Dr. Stephen Wilson, an assistant professor of psychology at the university, in a press release. “Namely, potential sources of reinforcement for giving up smoking — for example, the prospect of saving money or improving health — may hold less value for some individuals and, accordingly, have less impact on their behavior.”

Categorized in a grey area between a disease and a behavioral condition, addiction affects the brain in complex ways. People who smoke, or take virtually any drug, allow that drug to tap into their brain’s reward system. Thus, facilitating the release of dopamine and serotonin, the molecules responsible for feeling good and subsequently bringing a drug user back for more. This is evident in smokers who are most in need of a pull from their cigarettes whenever they’re sad, distressed, or angry, and say that it makes them feel more calm and relaxed.

But it turns out that these may be the only times these smokers are able to have such activity in their brain’s reward systems. The Penn researchers found that smokers who showed less activity in these areas, were unable to intrinsically produce such high quantities of the reward molecules. So, when given the opportunity to abstain from smoking a cigarette in return for a reward, some of them still went ahead and smoked.

The researchers discovered this with the help of functional magnetic resonance imaging, or fMRI, a kind of brain-imaging technology. For their experiment, they looked at the brains of 44 smokers, paying specific attention to the ventral striatum, where reward molecules are released and addiction is believed to be triggered. “It is the area of the brain that is important for motivation and goal-directed behavior — functions highly relevant to addiction,” Wilson said in the release.

All of the participants were nicotine deprived, having not smoked a cigarette for at least 12 hours before the experiment. While they underwent brain scans, they played a card-guessing game with monetary prizes. They were also told at the beginning of the experiment that they’d have to wait two hours to smoke, which was when the experiment would end. About halfway through the experiment, they were told differently, and given the opportunity to smoke during a 50-minute break that was 15 minutes away. When the time came to take the break — by this point, they were probably itching for a cigarette they thought they wouldn’t get until later — they were told that for every five minutes they didn’t smoke, they’d get $1, with the potential to collect as much as $10.

With that, the researchers were able to see who was able to resist a cigarette and who couldn’t. The fMRI scans showed that participants who exhibited less activity in their ventral striatum at the prospect of earning money were the ones more likely to go ahead and smoke. Conversely, those whose brains showed more activity were able to abstain.

“Our results suggest that it may be possible to identify individuals prospectively by measuring how their brains respond to rewards, an observation that has significant conceptual and clinical implications,” Wilson said in the release. “For example, particular ‘at-risk’ smokers could potentially be identified prior to a quit attempt and be provided with special interventions designed to increase their chances for success.”

With over 393,000 Americans dying each year from smoking, any intervention may be better than none at reducing the number of smokers. Smoking doesn’t only kill people but it also costs the U.S. over $193 billion in 2004 from health care expenditures and lost productivity, among other things.

Source: Wilson S, Delgado M, Grigson P, et al. Weak ventral striatal responses to monetary outcomes predict an unwillingness to resist cigarette smoking. Cognitive, Affective, & Behavioral Neuroscience. 2014.

 

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