Memory 'trick' relieves drug cravings

Researchers have come up with a way to help prevent recovering drug addicts from relapsing — without using other pharmaceuticals to help. The approach involves modifying addicts' behaviour by weakening their memory of drug taking, which relieves their cravings and might help to prevent relapse.

Addicts tend to associate a drug's effects with drug-taking equipment and a certain environment, which can make them vulnerable to relapse if they encounter those conditions. The technique, studied by Lin Lu of the National Institute of Drug Dependence at Peking University in Beijing and his colleagues, aims to break that link by briefly reactivating the memory of drug taking and following it with an 'extinction session' of repeated exposure to the same memory cues.

The short reminder of drug-taking seems to take the memory out of storage and make it easier to overwrite.

Seeing drug-taking equipment can prompt memories of a drug's effects and tempt ex-addicts to relapse.

Existing therapies try to help addicts to unlearn their habit by, for example, showing them videos of people injecting, and having them handle syringes while not under the influence of the drug. This reduces cravings in the clinic, but not when addicts return to their usual surroundings. Other approaches tested in rats involved using memory-blocking drugs to change memories of past drug use, but these are not approved for use in humans.

To boost the technique's effectiveness, Lu and his team combined the approach with a process called memory reconsolidation. During reconsolidation, information is retrieved from long-term storage and reactivated to strengthen the memory. After retrieval, however, the information becomes temporarily unstable and thus prone to alteration. Their work is published today in Science