Injecting alcoholics with ketamine could help them quit their boozing habits, according to new research.
But rather than swapping like-for-like, just one dose of medical therapy with the party drug could cut down people’s drinking for nine months or more, they said.
Ketamine blocks specific nerve pathways in the brain which are involved in creating the subconscious link between drinking and pleasure or reward.
And when problem drinkers were shown photos of beverages then given ketamine in a study, they appeared to be able to break their addiction and drink less often and less alcohol over the months afterwards.
Their weekly consumption of alcohol dropped by up to 50 per cent because they perceived drinking as less enjoyable.
Injecting alcoholics with ketamine could help them quit their boozing habits by wiping out pleasurable memories of alcohol, scientists say (stock image)
Lead author Dr Ravi Das, a psycho-pharmacologist at University College London (UCL), said: ‘We found heavy drinkers experienced a long-term improvement after a very quick and simple experimental treatment.’
Mind-altering drugs like ketamine, linked to illegal drug taking and rave culture, are illegal in the UK.
But science shows the drugs is able to conquer the brain’s reward system – which plays a crucial role in substance abuse.
Dr 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 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 is very difficult to re-learn more healthy associations, but it is vital in order to prevent relapse.’
Ketamine appears to work by interfering with how memories are formed, causing drinkers to forget the pleasure associated with alcohol.
By showing a beer cue before removing it, the participants memory of beer was reactivated, making it vulnerable to being broken down.
Normally, the brain would actively try to reinforce the link by, for example, leading someone to drink to satisfy the craving and restore the feeling of reward.
Ketamine prevents this process by doing something known as destabilising the memory, in which it blocks a receptor in the brain known as NMDAR (N-Methyl D-Aspartate Receptor).
The study involved 90 heavy male and female drinkers with an average age of 28, who had a particular thirst for beer.
They did not have a formal diagnosis of alcohol use disorder and had not sought treatment.
On average, they were downing about 30 pints (74 units of alcohol) a week, five times the recommended limit.
The volunteers were told they could drink a glass of beer once they had finished a task, according to the report in Nature Communications.
They were shown images of beer and other drinks, while scoring their likening of the drink and wish to have it. This retrieved the ‘reward memories.’
Then they rated their urge to drink the beer given to them and their predicted enjoyment of drinking it.
On the first day, in order to establish their baseline craving, they were allowed to drink the beer after the test. But on the second day, the beer was unexpectedly taken away.
The participants were split into three groups of 30 – one group received an intravenous infusion of ketamine and another group had a placebo.
The third group were given the drug, but hadn’t taken part in the memory retrieval task.
The participants were asked to report perceived changes in their drinking behaviour at a number of follow up appointments over the next nine months.
Those who were given ketamine combined with the memory retrieval task showed significant reductions in their urge to drink.
They also drank less alcohol and drank on fewer days than the others. When given a small sample of beer, they had less urge to drink it, enjoyed it less and had less desire to continue drinking than the other groups.
Only the two groups given ketamine showed a statistically significant reduction in drinking volume.
The effect was sustained over a nine-month follow-up. While all three groups decreased their drinking to some degree, those given the ketamine and memory retrieval had a much more initial and overall improvement.
They halved their average weekly alcohol intake over the whole study period by cutting the number of drinking days.
Blood tests also showed the treatment was more effective in people where the ketamine was most readily available in the body. This suggests a higher dose can lead to greater improvement.
However, the dosage used in the study was not made clear.
Dr Das said: ‘This is a first demonstration of a very simple, accessible approach, so we hope with more research into optimising the method, this could be turned into a helpful treatment for excessive drinking, or potentially for other drug addictions.’
Further research is needed to optimise the treatment method and determine who it could benefit, said the researchers.
Senior author Professor Sunjeev Kamboj, also of UCL, added: ‘Ketamine is a safe, common drug that is being explored for multiple psychiatric uses, including depression, while other researchers are also exploring other ways it could help with problem drinking.
‘An advantage to our study, alongside the pronounced, long term effect on drinking, is it is based on a strong understanding of how the drug is working in the brain to achieve its effect.’
Prof Celia Morgan, a psychopharmacologist at the University of Exeter, who was not involved in the research, said: ‘The idea is really intriguing and follows up other work blocking drug use behaviours by using similar drugs to interfere with re-consolidation in animals.
‘More recently people have tried this in humans but the findings of which have so far been mixed.
‘Ketamine is an addictive substance and associated with harms to bladder and a risk of accidents, so we have to be cautious when using it in groups who are prone to addictive behaviours.
‘But this is important work trying to drive the science of ketamine and memory forwards.’
Prof Matt Field, a psychologist at the University of Sheffield who was also not involved, said the findings are ‘promising.’ But he said further investigation with a larger number of people is needed.
The independent experts highlighted that participants in the control group also reduced their alcohol intake using a placebo.
Ketamine is an essential medicine on the NHS and globally. It is already a licensed aneasthetic, putting the patient in a trance like state so they cannot feel pain
It took off as a recreational drug in the 1980s. It has also been used as a date rape drug due to it being odourless and colourless.