Medication that increases levels of the brain chemical dopamine could open up new ways for helping some heavy users of cocaine and amphetamines kick the habit, researchers from Cambridge have found.

Cocaine and amphetamine abuse is increasing in the UK and relapse rates are high.

Dr Karen Ersche and colleagues from the University of Cambridge asked chronic stimulant users and volunteers who do not use drugs to perform a simple colour-naming test while their brains were scanned.

They found that the drug users performed the test just as well as the non-drug-taking volunteers as long as they were presented with neutral words. But when drug-associated words (drug cues) – such as sniff, coke or Charlie - appeared on the screen the drug users became distracted.

In the presence of drug cues drug users’ performance deteriorated and their brain activation changed, particularly in brain areas involved in self-control and memory.

However, when the drug users were given Parkinson’s Disease drug pramipexole their performance improved and their brain activation normalised. This beneficial effect was only seen in those drug users with a less compulsive pattern of using cocaine or amphetamines.

Dr Ersche said: “Our findings show that some heavy cocaine and amphetamine users may benefit from a mediation that corrects the amount of dopamine in their brains.”