The Cure for Drug Abuse? Changing People's MemoriesS

Even after drug users kick the habit, there's still the risk of relapse. And a big reason for this is fact that the person can still remember the pleasurable side of drug use. The solution might be to actually change the nature of those memories.

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That's the idea behind new research coming out of China's Peking University. While we're not quite at the point where we can wholesale implant — or, in the parlance of our times, incept — new memories that would make a person not want to do drugs, the researchers have come up with a subtler way to help drug users avoid a relapse in the very situation where they are most likely to be threatened: when they are surrounded by drug paraphernalia like needles, cigarettes, or whatever else.

The key idea is that drug users will have formed a positive association between the paraphernalia and the drug abuse, making them cues for drug use. Ideally, you'd want to completely flip what the drug cue means to the addict in question, so that seeing the cue would make them actively not want to use drugs — sort of like the therapy in Clockwork Orange only, you know, less horrific.

But inducing such total memory extinction is tricky, since it involves placing two contradictory, well-established memories in direct competition with each other. Instead, the researchers have figured out a rather elegant way to undermine the original memory. The technique relies on the fact that our brains have to "reactivate" our memories in order to access them, which basically means that for a short period after it is first recalled, the memory is actually flexible enough to be permanently altered. After that, the memory starts to harden again, locking in any changes that might have been made.

To illustrate this, the researchers gathered twenty-two recovering heroin addicts who had all been clean an average of eleven years. Before their actual drug therapy began, they were shown a video intended to remind them of their former drug use, which activated their memories linking together the drug cues with the pleasant side of their heroin use ("pleasant" may not be exactly the right word, admittedly).

Ten minutes later, they began working on the more traditional forms of memory extinction described above. Meanwhile, another group of addicts had only been shown a video of some idyllic countryside vistas, which one would hope was not able to reactivate their memories of drug abuse. They then underwent similar therapy.

At first glance, you might think that being confronted with vivid memories of their past life would make the former group more likely to experience cravings and potentially relapse. But when tested six months later, the first group actually reported significantly fewer and less severe cravings than their counterparts. Opening up the "memory window" before their drug therapy allowed them to reconstruct and reconsolidate their original memory, rather than simply contradict it. The researchers effectively tapped into a whole different process of memory creation and storage, one that hasn't previously been used in treating addiction.

It's early days yet, and obviously we'll need more extensive clinical trials than just 22 experimental subjects to know that this will definitely work. But the early results are encouraging, and similar trials on rats have helped confirm the researchers are on the right track.

Different sets of rats were made to retrieve drug-associated memories at different times before their own memory extinction sessions - either 10 minutes, an hour, or six hours ahead of time - and it was only in the first two cases where the retrieval sessions had any effect. That would indeed suggest that the memory window is what's crucial here, as its offers a brief period in which memories are flexible enough to, if not completely be rewritten, then certainly tampered with strategically.

Check out BBC News for more. Original paper and commentary at Science. Image by vigtuden, via Shutterstock.