Results of a new experimental study determine that a one-off dose of ketamine could enable heavy drinkers to reduce their alcohol intake by ‘erasing’ drink-related memories.
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Effective treatment for alcohol addiction needed
Psychologists at University College London have been conducting a study investigating the impact of a one-off dose of ketamine on heavy drinkers who are attempting to cut down their alcohol consumption. The team is aiming to develop an effective treatment for alcohol addiction, which is difficult to treat and for which there are limited effective treatment options available.
The study, published in Nature Communications, reveals that just one dose of ketamine is effective at decreasing drinkers’ urge to consume alcohol through ‘erasing’ drink-related memories. They observed that this effect led to a prolonged decrease in alcohol consumption over the nine months the heavy drinkers were observed for.
The researchers are optimistic that simple treatment may assist heavy drinkers in reducing their alcohol intake long-term.
Alcohol hijacks the brain’s reward-learning system
Alcohol addiction is difficult to treat because of the way it impacts the brain. The drug exploits the brain’s neural circuitry responsible for the reward-learning system, resulting in environmental factors acting as triggers, enhancing the desire to take the drug. In this way, the brain develops maladaptive reward memories that are difficult to forget, but erasing these memories is crucial to long-term improvement in drinking behaviors.
Ketamine prevents brain from re-establishing drinking memories
The experimental study looked at a group of 90 people who all presented harmful drinking behaviors but had no diagnosis of alcohol use disorder. During the study, participants were given a glass of beer, which was their preferred drink, and were told they would be able to drink it at the end of the task. The task involved looking at images of alcohol and rating their current urge to drink.
In rating their anticipated pleasure of drinking the beer, participants were accessing their reward memories related to drinking beer. On the first day, participants were allowed to drink the beer, but on the second day, researchers removed it unexpectedly, resulting in the destabilization of a retrieved reward memory.
In one group of participants, ketamine was administered to prevent the brain from re-stabilizing the memory, which is the active process the brain goes through after destabilization.
Ten days later, participants who were in the group who had been given ketamine combined with memory retrieval demonstrated a marked decrease in their desire to drink, resulting in consuming less alcohol over the ten days than the other experimental groups.
After nine months, participants in the ketamine plus memory retrieval task group had significantly decreased their alcohol consumption by half and had significantly reduced the number of days on which they consumed alcohol.
Of the other two groups, the one had been given a placebo, and the memory task had not significantly reduced their alcohol consumption, those who had been given just ketamine reduced alcohol consumption, but less so than the ketamine + memory retrieval group, and they did not reduce the number of days that they drank.
Blood tests revealed that the treatment was most effective in those who had the ketamine readily available in their blood, suggesting that higher doses might be even more effective.
Clinical trial required before therapy can be made available
The study showed that ketamine combined with the memory retrieval task might provide a simple, accessible, and cheap way to reduce drinking in those with alcohol problems effectively. The researchers also suggest that it has the potential to be developed to treat other substance addictions.
However, given that this was an experimental study rather than a clinical trial, much more research would need to be conducted before a clinically available therapy could be made available.
One shot of ketamine could reduce problem drinking. Eurekalert. Available from: https://www.eurekalert.org/emb_releases/2019-11/ucl-oso112519.php