Technique rewrites addicts' memories17th April 2012
Researchers in China have developed a technique that rewrites the memories of drug addicts to lessen their association with pleasure and help prevent them from relapsing.
The study's findings may be a useful addition to existing treatments for recovering addicts, who are vulnerable to relapse even after undergoing rehabilitation programmes which include "extinction procedures" to help patients control cravings.
Currently, recovering addicts are at risk of relapse if they come into contact with objects or situations that remind them of drug-taking, and existing programmes attempt to desensitise them to things or places associated with addiction by bringing them into contact with them while sober.
Such techniques are rarely effective once patients leave treatment and return to their former lives, however. Drugs which affect memory are also used, but patients often report unwanted side-effects.
Researchers led by Lin Lu of Beijing University's National Institute of Drug Dependence have shown that is possible to limit the rate of relapse among recovering addicts by rewriting the memories that are associated with triggers for cravings.
The treatment combines traditional extinction procedures with a new process which the team, writing in the journal Science, calls memory reconsolidation.
The process involves reawakening memories of drug-taking from patients' long-term memory. The retrieval process renders the memory temporarily unstable as it comes to consciousness, and vulnerable to alteration for a brief window of time.
Lu's team first carried out experiments on rats which had learned to take cocaine and heroin in a specific environment. They found that rats that were removed from the drug-taking environment shortly after being put there and reintroduced to it after 10 minutes showed the least drug-seeking behaviour.
Translating their findings to humans, the researchers then showed recovering heroin addicts a short video of images of heroin use and other environmental factors designed to suggest drug-taking to them.
Some of the group were shown videos of the kind already traditionally used in extinction programmes, which expose patients repeatedly to images of drug-taking in an attempt at desensitisation, 10 minutes later. A second group was shown the same video six hours later.
The 10-minute group showed less reaction to drug-taking behaviours both during the extinction session and for up to six months later, Lu and his team reported. There was no significant effect on the cravings experienced by the 6-hour control group, on the other hand.
The authors concluded that the memory procedure they had devised was effective in decreased drug-cravings induced by environmental triggers, and could also possibly reduce the likelihood of relapse for prolonged periods.
The speculated that the treatment might work by destabilising the memories induced by the initial video during the brief period that elapsed between the first and the second video. This would wipe out the positive link between the images of drug-taking and the pleasurable memories of getting high, rewriting the patient's memory as if the link had never existed.
Experts welcomed the findings, saying that such a small alteration to current treatment programmes could have a big impact on the rehabilitation of addicts.
They called for further clinical studies to confirm the results, which could also be used in the treatment of other addictions, including alcohol.
Cambridge University addiction researcher Amy Milton said the research was "very exciting".
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Title: Technique rewrites addicts' memories
Author: Luisetta Mudie
Article Id: 21665
Date Added: 17th Apr 2012