London: A one-off dose of party drug ketamine may help heavy drinkers significantly reduce their alcohol intake, an experimental study claims. The study suggests that giving a shot of ketamine to heavy drinkers after reactivating their drinking-related memories led to a rapid decrease in urges to drink, and a prolonged decrease in alcohol intake over nine months.
"We found that heavy drinkers experienced a long-term improvement after a very quick and simple experimental treatment," said the study's lead author, Ravi Das, from University College London (UCL) in the UK. "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," Das explained.
He said that once these reward memories are established, it's very difficult to re-learn more healthy associations, but it is vital in order to prevent relapse. The study involved 90 people with harmful drinking behaviour, who all preferred beer. The participants were heavy drinkers, but did not have a formal diagnosis of alcohol use disorder and had not sought treatment.
They rated their urge to drink and were shown images of beer and other drinks, while rating their anticipated pleasure, thus retrieving the reward memories surrounding beer drinking. On the first day of the study, in order to establish their baseline drinking urges, they were then allowed to drink the beer, but on the second day, the beer was unexpectedly taken away from them.
Removing an anticipated reward is known to be key factor to destabilising the memory of the removed reward. Typically the brain would then undergo an active process to re-stabilise, and store the reward memory of having alcohol.
However, ketamine prevents this memory re-storage process by blocking a receptor in the brain that is needed to restabilise memories. One third of the study participants were then given an intravenous infusion of ketamine after the beer was taken away from them.
Another group was given an infusion of a placebo, while the other third were given ketamine, but without previously completing the drinking memory retrieval task. The method appeared to be successful, as over a 10-day follow-up, the people who were given ketamine combined with memory retrieval halved their average weekly alcohol consumption, the researchers said.