Several decades ago, a number of clinics used LSD to treat alcoholism with some success.
But until now, no research has pulled together the results of these trials to document exactly how effective LSD was.
Now a new meta-analysis of randomised controlled trials of the drug provides evidence for a clear and consistent beneficial effect of LSD for treating alcohol dependency.
Teri Krebs and Pal-Orjan Johansen, both affiliated with the Department of Neuroscience at the Norwegian University of Science and Technology (NTNU), Trondheim, Norway, spotted a gap in the understanding of LSD's potential for alcoholism treatment during research fellowships at Harvard Medical School, Boston, USA.
Krebs and Johansen set out to independently extract data from previous randomised, controlled clinical trials, pooling their results.
They identified six eligible trials, all carried out in the late 1960s and early 1970s. These included 536 participants, the vast majority of whom were male in-patients enrolled in alcohol-focused treatment programs.
While the experiments varied in the dosage used and the type of placebo physicians administered to patients, LSD had a beneficial effect on alcohol misuse in every trial.
On average, 59 percent of LSD patients and 38 percent of control patients were improved at follow-up using standardized assessment of problem alcohol use. There was also a similar beneficial effect on maintained abstinence from alcohol.
The positive effects of a single LSD dose - reported both in these and in other, non-randomized trials - lasts at least six months and appears to fade by 12 months.
Regarding the lasting effects of the LSD experience in alcoholics, investigators of one trial noted, "It was rather common for patients to claim significant insights into their problems, to feel that they had been given a new lease on life, and to make a strong resolution to discontinue their drinking".
And investigators of another trial noted, "It was not unusual for patients following their LSD experience to become much more self-accepting, to show greater openness and accessibility, and to adopt a more positive, optimistic view of their capacities to face future problems."
LSD interacts with a specific type of serotonin receptors in the brain, which may stimulate to new connections and open the mind for new perspectives and possibilities, according to Krebs.
LSD is not known to be addictive or toxic to the body, but the LSD has striking effects on imagination, perception, and memories and can elicit periods of intense anxiety and confusion.
Krebs and Johansen suggest that repeated doses of LSD coupled with modern, evidence-based alcohol relapse prevention treatments might provide more sustained results.
They also noted that plantbased psychedelics such as mescaline and ayahuasca which are used by Native Americans to promote mental health and sustianed soberity, merit further investigation for alcoholism treatment.
Details of the study are available in the Journal of Psychopharmacology, published by SAGE.