Ketamine Could Be Used To Reduce Heavy Drinking, Study Finds

The results of an experimental study suggest a one-off dose of ketamine could be used to help heavy drinkers cut back on their alcohol intake. 

Ketamine is probably best known for being a recreational drug or an animal tranquilliser, and while neither of those uses seem like they would be beneficial to heavy drinkers, apparently the substance does have some qualities that apply.

The study was inspired by a growing body of evidence suggesting ketamine can be used to disrupt or ‘rewrite’ memories addicts may be drawing upon when engaging in harmful patterns of behaviour, like when someone learns to associate an environmental trigger with the urge to have a drink.

Researchers conducted the experiment on 90 people who had hazardous levels of drinking, with participants drinking an average of 74 units of alcohol – roughly 30 pints of beer – per week, which is five times the recommended limit.

However, those taking part had not been formally diagnosed with alcoholism, nor were they seeking treatment.

On the first day of the study, a glass of beer was placed in front of the participant and they were told they would be allowed to drink it after viewing some images of beer and people drinking. They were also asked to rate their urge to drink and the pleasure it would give them.

The routine was repeated the following day, but this time the glass of beer was taken away.

After the beer was taken away, one-third of the participants were given a small dose of ketamine via intravenous drip, another third were given a placebo infusion and the final group received the ketamine but without the psychological intervention.

Removing an anticipated reward is known to temporarily disrupt associations that have formed in the brain, though the memory normally re-stabilises shortly after the experience.

However, ketamine blocks a brain receptor called NMDA, which is required for the formation of memories, so the scientists used the short period of instability as an opportunity to rewrite drink-related memories.

Explaining the process, the leader of the trial, Dr Ravi Das, said:

Learning is at the heart of why people become addicted to drugs or alcohol. Essentially, the drug hijacks the brain’s in-built reward-learning system, so that you end up associating environmental ‘triggers’ with the drug.

These produce an exaggerated desire to take the drug. Unfortunately, once these reward memories are established, it’s very difficult to relearn more healthy associations, but it’s vital in order to prevent relapse.

The study, published in Nature Communications, found over the next 10 days the people who were given ketamine combined with the psychological intervention showed significant reductions in their urge to drink. They also drank less alcohol and drank on fewer days than the other study participants.

The effect of the study even seemed to extend into the long term, as over the following nine months all three groups decreased their drinking, though those given the ketamine therapy showed the best overall improvement by halving their average weekly alcohol consumption.

Das, a psychologist at University College London, commented:

There was a really big drop-off, which was maintained or got even better up to nine months [after treatment]. I was surprised by how effective it was.

Every behaviour is encoded in our memories. An important takeaway is that these habits and unhelpful memories can potentially be unlearned.

The team is applying for funding to carry out a clinical trial to investigate whether the therapy could help people with alcohol addiction.

Scientists cautioned the study is experimental and pointed out further research is needed to optimise the treatment method.

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