ľ��ֱ��

Brain Damage May Make Smokers “Forget” to Smoke

Some smokers with damage to a part of the brain called the insula may have their addiction to nicotine practically eliminated, according to a new study. If the findings of this small study are confirmed, the discovery could open the door to new strategies for helping people to quit smoking.

Cigarette smoking is the most common preventable cause of illness and death in the world. While most smokers are aware of the health consequences of smoking, they can find it very difficult to quit. Even those who do successfully quit often feel the urge to smoke.

Brain imaging studies have shown that particular regions of the brain are activated when people are exposed to smoking cues. In work supported by NIH's National Institute on Drug Abuse (NIDA) and National Institute of Neurological Disorders and Stroke (NINDS), Dr. Antoine Bechara of the University of Southern California and his colleagues explored the connection between smoking and a region called the insula. Researchers believe that the insula may be involved in the emotional processing that promotes drug use.

Bechara and his colleagues identified 19 smokers who had experienced brain damage that included the insula. Of these, 13 had quit smoking after their brain damage. The team also identified 50 smokers whose brain injuries didn't include damage to the insula. Of these, 19 had quit smoking.

The scientists described their findings in the January 26, 2007, issue of the journal Science. The likelihood of quitting smoking was not significantly different between the two groups. However, some smokers seemed to quit much more easily than others. For a closer look, the scientists developed four criteria to determine whose smoking addiction had been disrupted by brain injury: (1) they had quit smoking less than one day after the brain injury; (2) their difficulty of quitting was less than three on a scale of one to seven; (3) they did not smoke again after quitting; and (4) they had no urge to smoke since quitting.

Twelve of the 13 people who quit smoking following damage to their insula met these criteria, as opposed to only four of 19 who quit after damage to other brain areas.

“Participants with damage to the insula were overwhelmingly more likely to experience a true disruption of the urge to smoke, characterized by an almost immediate cessation of smoking with no reported struggles to maintain their abstinence,” Bechara said. “Damage to the insula could lead smokers to feel that their bodies have ‘forgotten’ the urge to smoke.”

Additional research is needed to replicate the findings of this small study. If they are confirmed, medications that target receptors within the insula may offer promise for more effective smoking cessation therapies in the future.