How the urge to smoke can just vanish
Smokers with injuries in a specific part of their brains kick their habits instantly -- without the intense cravings that can make it so hard to quit, a new study reports today.
The researchers from USC and the University of Iowa linked a brain area called the insula to the powerful urges that cause people to continue smoking.
Smokers with damaged insulas were 136 times more likely to have their addictions erased than smokers with damage in other parts of their brains, researchers said.
One man who smoked an average of 40 cigarettes a day before a stroke damaged his insula was surprised to suddenly lose all cravings for tobacco. He told researchers his body "forgot the urge to smoke."
"It was like a switch was turned off," said Antoine Bechara, a neuroscientist at USC and senior author of the paper.
The research in the journal Science opens a new front in addiction research and could lead to improved treatments for smokers, experts say.
Though intentionally damaging the insula would be too risky, it might be possible to develop drugs or medical devices that could temporarily disable the region's circuitry, relieving smokers of the urge long enough for them to quit, scientists said.
But Jed Rose, director of the Center for Nicotine and Smoking Cessation Research at Duke University, cautioned against drawing broad conclusions from the research. Rose, who was not involved in the research, said people with conditions such as attention-deficit disorder have high rates of smoking, suggesting different regions of the brain might also be important in such people.
Of the 45 million Americans who smoke, 400,000 die annually of illnesses related to smoking. Rose said no more than 5% of smokers are able to permanently quit on their own.
Most smoking research has focused on the cortex, the brain region involved in reasoning and decision making. Nicotine in tobacco prompts the release of brain chemicals in the cortex that generate pleasurable feelings. Smoking addiction has been largely understood as a drive to feel pleasure, said Caltech neurobiologist Henry Lester.
Smoking-cessation drugs target the brain's pleasure circuitry but are not very effective in helping smokers quit over the long term, Rose said.
The researchers examined 32 former smokers who had suffered some form of brain damage. The patients were asked how hard it was for them to stop smoking and whether they felt any urges to smoke after they quit.
