Millions of people pledge to ditch the booze every January, but experts are divided over whether going dry for a month is the answer to the UK’s troubled relationship with alcohol.

According to recent figures, around four-fifths of adults drink in England, with 31% of all men and 16% of all women consuming more than the recommended limit of 14 units in a usual week. As well as increasing the risk of injuries, damage to unborn babies, heart disease, liver disease and stroke, alcohol is also known to increase the risk of a number of cancers, among other effects.

But while campaigns such as Dry January, run by the charity Alcohol Concern, have become increasingly popular – an estimated five million people took part in 2017 in the UK – experts speaking to the Guardian said they were conflicted about whether the initiatives help to change behaviour in the long term, and whether they were the right approach for many who regularly overindulge.

“I think [it] would help everyone if there was a more robust evaluation of what goes on after Dry January,” said Ian Hamilton, a lecturer in mental health and addiction at the University of York.

Hamilton questioned whether such campaigns could really help people “reset their relationship with alcohol”, as they often claim to. “I am very sceptical about that,” he said. “The millions of people who sign up to it are the millions of people who probably don’t have that great a problem with alcohol so they find it relatively easy.”

Those with an alcohol problem were unlikely to be helped by the campaign, he said, adding that even if they signed up, it was inadvisable for dependent drinkers to give up alcohol abruptly since it could result in side effects ranging from headaches to convulsions. “I think anyone drinking several glasses of wine after work each day should seek support before they abstain completely from alcohol,” he said.

However, Clare Hyde, a health information officer at Cancer Research UK, which runs the Dryathlon campaign, another booze-free January challenge, said there was no problem with very regular drinkers taking part in the movement.

“I think in terms of dependency, we would be talking about people who have a dependency in a more clinical sense – it wouldn’t just be people who are drinking a lot or drinking regularly,” she said, although she added that anyone who does experience withdrawal symptoms should speak to their doctor.

One of the reasons experts disagree, perhaps, is that little scientific research has been done into the effects of taking one month off booze.

One oft-cited study was carried out in 2013 by Rajiv Jalan, professor of hepatology at University College London, on a small group of staff from New Scientist magazine. He found that the 10 individuals who gave up booze for a month showed significant health improvements compared to the four colleagues who did not abstain, with an average 15% drop in liver fat among the positive results.

Jalan told the Guardian that his team had recently completed new research into the issue, which is not yet published, comparing health data from 93 healthy hospital employees who undertook Dry January with 48 healthy individuals who did not.

While not a randomised trial, Jalan said the results were striking. “What we found was a pretty astonishing result in terms of improvement of almost everything we looked at,” he said, noting that those who abstained lost weight and reported better skin condition and concentration.

“Their liver function improves, liver stiffness improves,” Jalan added, although he noted more work was needed to probe whether benefits continued long-term, or were lost when drinking resumed.

As for whether a month’s abstinence can change behaviour, one study published in 2015 and co-authored by researchers from Alcohol Concern, found just under 60% of the 857 Dry January participants quizzed said that six months after the campaign they drank on fewer days per week than in the previous year, whether successful in their abstinence or not.

But the study did not look at trends in those not abstaining for a month, among other limitations, while behaviour change was more pronounced among those who had been successful. Jalan said follow-up questionnaires from about 30% of the participants in his latest study did suggest that those who gave up alcohol for January had lower alcohol consumption six months later. “We think that is because they felt so much better at the end of that month,” he said.

Dr Richard Piper, CEO of the merged Alcohol Research UK and Alcohol Concern charities, said that his organisation was engaged in new research to take a more robust look at the impact of Dry January, although he too stressed the campaign is not for those with an alcohol problem.

Nick Sheron, professor and head of clinical hepatology at the University of Southampton, pointed out, however, that alcohol dependency is a grey area. “It is not a black or white thing,” he said. “Pretty much everybody who is drinking on a daily basis has a degree of alcohol dependence and will have a degree of tolerance to their alcohol as well.”

Alcohol Concern itself appears to err on the side of caution. “If you regularly drink more than the government’s recommended maximum of 14 units of alcohol per week, you may be alcohol dependent, and in this case Dry January is not for you,” the website states.

The worry, said Hamilton, is that Dry January could exacerbate difficulties among those with an alcohol dependency – with many likely unaware that they have such a problem. “The problem for them is that if they start Dry January and don’t complete it, which I don’t think they will, it does nothing for their confidence,” said Hamilton, noting that that could discourage them from seeking help.

“They may well realise they have a problem with alcohol – but then what do they do?” he added. According to Hamilton, more resources for supporting those with alcohol dependancy are needed. “We know that treatment services for people who do develop problems with alcohol have been savagely cut – so in some ways [these campaigns are] a distraction from people who really do have a problem,” he said.

Hamilton added that there was an additional risk that those who had given up booze for a month might then over-indulge in February. “At a drop of a hat I would scrap dry January in favour of people abstaining for two days a week – I think that would be far, far better,” he said.

Colin Drummond, professor of addiction psychiatry at King’s College London, said that in light of the huge advertising campaigns by the alcohol industry, attempts to encourage individuals to drink less were to be welcomed.

But he, too, said more research was needed. “There has been remarkably little proper valuation of campaigns like Dry January,” said, adding that such initiatives are “blunt instruments” that work best for lighter drinkers.

While Hyde agreed that cutting down generally over the long term might be advisable, she said there were still benefits to going teetotal for a month.

“Realistically we know that if you did want to make a bigger change [to your cancer risk] you’d have to cut down over a longer period of time,” she said. “[But] that doesn’t mean to say that Dryathlon isn’t good or doesn’t have health benefits – we think Dryathlon could be the catalyst to kick start a change that could have a real impact on your cancer risk.”