March 13, 2014
Understanding Why It’s So Hard To Quit Smoking
Lee Rannals for redOrbit.com - Your Universe Online
Previous studies have found that up to 80 percent of those who attempt to quit smoking end up relapsing. The latest study may shed some light as to why this high number of relapses occur.
Scientists from University of Pennsylvania School of Medicine and the National Institute on Drug Abuse (NIDA) Intramural Research Program performed a brain imaging study to look at smokers attempting to kick the habit. They found that smokers who abstained from cigarettes showed weakened interconnectivity between certain large-scale networks in their brains.
"What we believe this means is that smokers who just quit have a more difficult time shifting gears from inward thoughts about how they feel to an outward focus on the tasks at hand," said Caryn Lerman, PhD., who is also the deputy director of Penn's Abramson Cancer Center. "It's very important for people who are trying to quit to be able to maintain activity within the control network — to be able to shift from thinking about yourself and your inner state to focus on your more immediate goals and plan."
Other research has looked at the effects nicotine has on the brain’s interconnectivity in resting state. However, this was the first study to compare resting brain connectivity in an abstinent state and when people are smoking as usual and then relate those changes to symptoms of craving and mental performance.
Researchers conducted brain scans on 37 healthy smokers between ages 19 and 61 using functional magnetic resonance imaging (fMRI) in two different sessions. The imaging showed a significantly weaker connectivity between the salience network and default mode network during abstinence. The team also found weakened connectivity during abstinence was linked with increases in smoking urges, negative mood, and withdrawal symptoms. These findings suggest that this weaker interconnectivity could be what is making it difficult for people to kick the habit.
The authors propose that establishing the strength of the connectivity between these brain networks will be important in predicting people’s ability to quit and stay quit.
"Symptoms of withdrawal are related to changes in smokers' brains, as they adjust to being off of nicotine, and this study validates those experiences as having a biological basis," Lerman concluded. "The next step will be to identify in advance those smokers who will have more difficultly quitting and target more intensive treatments, based on brain activity and network connectivity."