Tobacco Addiction's Source Revealed In The Brains Of Stroke Victims

Scientists discover that smokers suffer from strokes in the brain's insular cortex and are therefore more likely to leave the habit. This has helped them to get an insight into the source of addiction, according to addictionjournal.

Those who had strokes in the insular cortex usually tend to undergo less withdrawal symptoms than others who had them in other parts of the brain, the University of Rochester reported.

"These findings indicate that the insular cortex may play a central role in addiction," said Amir Abdolahi, lead author of the studies. "When this part of the brain is damaged during stroke, smokers are about twice as likely to stop smoking and their craving and withdrawal symptoms are far less severe."

To treat tobacco addiction, drugs such as bupropion and varenicline, which are aimed at the brain's "reward" pathways and interfere with the the binding of dopamine in the brain, in response to nicotine, tend to help. Such drugs exhibit high rates of relapse, even as the success rates show only 30 percent after six months.

As scientists are familiar with the concept of the insular cortex playing a major role in addiction, a team of researchers examined the link by 156 stroke patients and smokers hospitalised in three hospitals in Rochester, N.Y. When the researchers looked at the site where they had their stroke and the severity of their nicotine withdrawal symptoms, they found that as their insular cortex had got affected, they experienced fewer and less severe symptoms such as anger, anxiety, cravings, lack of concentration, hunger, sadness, and trouble sleeping.

They also found almost twice as many patients, ie 70 percent versus 37 percent, who had strokes in the insular cortex, were able to successfully give up smoking, after they went through "wake up call" health issues. Scientists thus believe that in order to de-addict, they need to target the insular cortex through drugs or deep brain stimulation.

"Much more research is needed in order for us to more fully understand the underlying mechanism and specific role of the insular cortex, but is clear that something is going on in this part of the brain that is influencing addiction," Abdolahi concluded, according to hngn.

The findings were published in a recent edition of the journal Addiction.