Scientists find ‘addictive centre’ in brain

Scientists have pinpointed the source of nicotine addiction — a one-inch wide pleasure centre deep within the brain. The insula, a small island in the cerebral cortex, has been described as a “platform for feelings and emotion”.

Researchers found smokers who suffered damage to this part of the brain were able to quit quickly and easily. They suspected the insula might also be involved in other forms of addictive behaviour that keep people hooked on drugs or excessive eating.

Understanding the link could lead to new strategies for dealing with addiction.

The discovery came about after scientists in the US learned of a heavy smoker whose dependency on cigarettes was miraculously broken after a stroke damaged his insula.

The man, who had smoked 40 cigarettes a day, quit immediately. He told researchers that his body “forgot the urge to smoke”.

A subsequent investigation of 69 brain-damaged smokers revealed 19 who had suffered insula injury. Of these, 13 gave up smoking, all but one without any difficulty.

The researchers do not know why the six others failed to quit smoking.

Study leader Antoine Bechara, from the University of Southern California (USC) in Los Angeles, said: “One of the most difficult problems in any form of addiction is the difficulty in stopping the urge to smoke, to take a drug, or to eat for that matter. Now we have identified a brain target for further research into dealing with that urge.”

The insula receives information from other parts of the body and is thought to help translate those signals into something that is subjectively felt, such as hunger, pain or a craving.