New research suggests that cocaine use could lead to "profound changes" in the brain that make relapse more common in addicts.

Researchers at the University of East Anglia identified a molecular mechanism in the reward centre of the brain that influences how recovering cocaine addicts might relapse after stressful events. It also identifies a potential mechanism for protecting against such relapses with treatment.

"Relapse among cocaine addicts is a major problem. We wanted to find out what causes it," Peter McCormick, lead researcher of the study, said in a statement. "Neuropeptides are messenger molecules that carry information between neurons in the brain. They form the brain's communications system."

For the study, researchers looked at the effects of cocaine in rat brain cells (in vitro) and in live rats -- particularly their 'cocaine seeking' response to stress.

"Our research showed that the release of neuropeptides influences activity in this part of the brain and that profound changes occur at the neuroreceptor level due to exposure to cocaine," McCormick said.

Their study showed that cocaine disrupts the interaction between receptors and these changes could increase the risk of relapse under stressful conditions.

The findings are detailed in The Journal of Neuroscience .