Smokers who suffered from strokes in their brain's insular cortex were found to be more likely to quit, and the findings could shed light on the source of addiction.

Individuals who experienced strokes in the insular cortex generally experienced fewer withdrawal symptoms than those who had strokes 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."

Current popular medications used to treat tobacco addiction include bupropion and varenicline, which target the brain's "reward" pathways by interfering with the binding of dopamine in the brain in response to nicotine. These drugs have relatively high rates of relapse, with success rates of only 30 percent after six months.

Past research has suggested the insular cortex could play a major role in addiction, so a team of researchers investigated the link by 156 stroke patients who were admitted to three hospitals in Rochester, N.Y, all of whom identified themselves as smokers. While the patients were hospitalized, the researchers looked at the location of their stroke as well as the severity of their nicotine withdrawal symptoms. The study revealed patients who had a stroke in their insular cortex experienced fewer and less severe symptoms such as anger, anxiety, cravings, lack of concentration, hunger, sadness, and trouble sleeping.

The participants were also followed for a period of three months, and found almost twice as many patients (70 percent versus 37 percent) with strokes in the insular cortex successfully quit smoking after their "wake up call" health complications. The researchers believe these findings could potentially lead to ne addiction therapies that 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.

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