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The psychedelic drug LSD can help people with alcoholism quit or cut back their drinking, according to a new analysis of data originally collected in the 1960s. The study adds to a renaissance of research interest in mind-expanding medications for psychiatric disorders.

Norwegian scientists conducted a meta-analysis, combining the results of six randomized trials that tested the effect of a single dose of LSD for alcoholism in 536 adults. Researchers found that 59% of participants who took acid either dramatically cut back their drinking or quit, compared with 38% of controls, who either took a much smaller dose of acid or used another drinking-prevention treatment. Only eight cases of adverse effects or “bad trips” were reported, none of them lasting longer than the high itself.

Earlier conclusions from the literature have suggested that LSD was not effective for alcoholism, but those results appear to e related to the fact that individual studies on the subject did not include enough participants to demonstrate significant differences between the groups.

“LSD had a significant beneficial effect on alcohol misuse at the first reported follow-up assessment,” write the authors of the new paper, published in the Journal of Psychopharmacology. “The effectiveness of a single dose of LSD compares well with the effectiveness of daily naltrexone [reVia, Vivitrol] acamprosate [Campral], or disulfiram [Antabuse].” Those are the drugs currently approved by the Food and Drug Administration to treat alcoholism.

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The study found that the differences between LSD and control groups were statistically significant from two months to six months after treatment, but one year later, there was no longer a measurable improvement in those who had taken LSD. But given the persistence of alcoholism, it is perhaps more surprising that the effects of one dose of LSD lasted up to six months than it is that it would “wear off” a year later.

The treatment of alcoholism using LSD is not as unconventional as it may appear to the unitiated. In fact, AA co-founder Bill Wilson was an early advocate of acid treatment for alcohol abuse; unlike some of his followers, Wilson never believed that AA was the only way to deal with alcoholism. He took LSD himself, finding that the mind-expanding substance facilitated a similar spiritual state to the one that had helped him stop drinking in the first place. In his official AA biography, Pass It On, he’s quoted as saying:

It is a generally acknowledged fact in spiritual development that ego reduction makes the influx of God’s grace possible. … I consider LSD to be of some value to some people, and practically no damage to anyone. It will never take the place of any of the existing means by which we can reduce the ego, and keep it reduced.

Similarly, the rationale for the treatment regimen used in some of the early LSD trials was that the powerful drug would “break down” alcoholics’ egos and thereby create a spiritual awakening. This was not supposed to be a fun or mellow trip.

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For example, in one of the trials included in the current analysis, the patients were actually strapped to their beds within a therapeutic community, a setting that typically involves extensive confrontation and humiliation aimed at revising their personalities. Research now shows, rather unsurprisingly, that trying to annihilate people emotionally is dangerous and can lead to long-term damage, even when it’s done without a powerful hallucinogen. Previous studies on LSD suggest that researchers may have underestimated the drug’s potential by using it as part of a counterproductive therapeutic strategy.

Studies show that the psychedelic experience is very sensitive to context, which is why the CIA used the drug as an interrogation aid while hippies viewed it as vehicle for bring about worldwide peace and love.

But acid is not the only psychedelic drug that has shown promise in addiction treatment. An African drug, ibogaine, was also found in early trials to reduce or even eliminate withdrawal symptoms from heroin while producing an intense and often emotionally exhausting trip.

This property was discovered in 1962 by a heroin addict, Howard Lotsof, who took ibogaine on the street and found that afterward, he no longer felt physical withdrawal symptoms or craving. He stayed off heroin, patented the use of ibogaine for treatment of multiple addictions and spent the rest of his life advocating for more research. Unfortunately, the drug remains tangled in controversy due to deaths associated with street use and the lingering taint of the 1960s that shadows all psychedelic-drug research.

Still, with increasing data suggesting that psychedelics, including MDMA (ecstasy) and psilocybin (mushrooms), may be useful in the treatment of psychiatric disorders ranging from depression to post-traumatic stress disorder, perhaps careful study will finally determine a role for these kinds of treatments in psychiatry.

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In addiction research, however, it’s important to temper enthusiasm and keep from overselling psychedelic “cures.” Lotsof once told me about what happened to some of his friends after they discovered that ibogaine had gotten him through heroin withdrawal with no struggle.

As predicted, his fellow addicts reported the same lack of withdrawal. Like Lotsof, his friends also felt free — they no longer felt a physical need for heroin. But unlike Lotsof, his friends had no desire to quit; they continued to score heroin because they wanted to get high. It suggests that addiction is much more than withdrawal, physical dependence and craving.

Psychedelic experience — like all other intense life events — may offer the potential for growth and change. How people respond, however, depends on far more than a drug.

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Maia Szalavitz is a health writer for TIME.com. Find her on Twitter at @maiasz. You can also continue the discussion on TIME Healthland‘s Facebook page and on Twitter at @TIMEHealthland.