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Child Psychiatrist /Adult Psychiatrist

Do the Data Support Psychedelics in Addiction Therapy?

Updated: Sep 15, 2023

a person sitting on a yellow couch


PARIS — "We need to develop new therapies to treat addiction because of the related cost to society, which is extremely high," said Bruno Roméo, MD, psychiatrist and addiction specialist at the Paul Brousse Hospital in Villejuif, France, at the Paris-based Neuroscience, Psychiatry and Neurology Conference. Roméo spoke about the current place of psychedelics in the treatment of addiction.

"Smoking and alcohol consumption are the two main preventable causes of death in France," he said. "Current management strategies for these addictions rarely involve pharmacological therapies, which are not very effective, in any case. We have massive relapse rates, signaling the need to develop other treatments, like psychedelic drugs."

But what data are available on the efficacy of psychedelics in treating addiction?

Alcohol Use Disorder

There are few data concerning the role of psychedelics in the treatment of alcohol use disorder, but one controlled, randomized trial evaluated the efficacy of psilocybin. That trial was published in JAMA Psychiatry in 2022.

That study included 95 patients with alcohol use disorder; 49 were treated with psilocybin, and 46 were treated with diphenhydramine.

An initial medication session of psilocybin was given in week 4, then another in week 8 at a higher dose. The number of drinking days, the number of heavy drinking days, and the number of drinks consumed between weeks 32 and 36 were assessed.

The investigators showed that after two sessions with psilocybin, there was a significant reduction in the number of heavy drinking days. In the control group, between weeks 5 and 36, 20% of days involved heavy drinking, whereas in the psilocybin group, 10% of days involved heavy drinking.

There was also a significant and rapid reduction in the number of drinking days, and this was maintained over time. Between weeks 5 and 36, just over 40% of days were reported as drinking days in the control group, vs slightly more than 30% in the psilocybin group.

Similarly, the number of glasses per day was drastically reduced after taking psilocybin, and the effect occurred extremely quickly. Consumption went from six drinks to less than one drink between weeks 5 and 8. Overall, between weeks 5 and 36, the number of drinks consumed per day was more than two in the placebo group and more than one in the psilocybin group.

"Psilocybin was seen as having potential efficacy in treating alcohol use disorder. But we must tread carefully with these results; the profile of the patients enrolled in this study is different to that of the patients we regularly see in our addiction clinics. The patients enrolled in the study reported less than 60% of days as heavy drinking days," said Romeo.

Candidates for Psilocybin

According to a retrospective survey of 160 respondents that was conducted online at the Paul Brousse Hospital, patients with the most severe cases of alcohol use disorder who have the most mystical psychedelic experiences seem to respond best to psilocybin and to reduce their alcohol use. It also appears that patients whose alcohol use decreased the most had lower psychological flexibility on enrollment in the study. (Psychological flexibility is the ability to adapt to change and to cope with positive and negative experiences in real time without being fazed or trying to flee from the situation.) "It's as if they had a broader capacity for change, and psychedelics helped them more," said Roméo.

Smoking Cessation

"There are even fewer studies for smoking," said Roméo. In a pilot study with 15 patients, the researchers gave two or three doses of psilocybin at 20 mg to 30 mg in combination with cognitive-behavioral therapy one session per week for 10 weeks. Thereafter, patients were assessed three times: after 6 months, 12 months, and 30 months.

The results showed a significant reduction in smoking. Patients went from smoking more than 15 cigarettes per day to smoking one to two cigarettes per day before going back up to six cigarettes daily.

Regarding abstinence rates, 12 of 15 patients had stopped smoking after 6 months, eight of 15 after 1 year, and seven of 15 after 30 months. "This study produced some interesting results, although caution must obviously be taken due to the very low number of patients enrolled," said Roméo. As is the case for alcohol, a retrospective survey conducted via questionnaire at the Paul Brousse Hospital showed that the patients who smoked the most and who had the most mystical psychedelic experiences seemed to respond best to psilocybin and therefore to reduce their tobacco use. It also seemed to be the case that patients who reduced tobacco use the most had lower psychological flexibility on enrollment in the study.

Constraints on Psychedelics

"Psychedelics are somewhat effective in treating addiction, but there are various limitations to their use," said Roméo. One of those limitations is societal. Laurence Bézo, MD, of the addiction services clinic at Paul Brousse Hospital, asked doctors to respond to a questionnaire to determine what they thought about psychedelics. To date, 407 have responded, including 280 general practitioners, 50 addiction specialists, and 50 specialist physicians. Overall, 50% think that psychedelics have no therapeutic potential. Three of five doctors also said that psychedelics are dangerous. Just over half thought that their use is associated with a severe risk of aggression aimed at oneself and toward others. Likewise, half think that the risk of dependency is very high and that there is a risk of co-occurring psychiatric disorders. "From the pool of physicians queried, the consensus is that psychedelics are pretty dangerous. People also seem to frown upon prescribing psychedelics in France," said Roméo.

Participants went as far as to classify psychedelics as some of the most dangerous drugs out there.

Using a 7-point scale, they classified psychedelics below heroin and cocaine in terms of dangerousness. They are deemed much more harmful than alcohol, tobacco, and cannabis.

"A survey of the public carried out several years ago by leading French market research group IFOP had the exact same findings. Nevertheless, a number of studies have set out to determine how dangerous psychedelics are, and their findings point to this class of drugs as being among the least harmful for the individual patient and those around them. On the contrary, alcohol, heroin, crack cocaine (or even cocaine),methamphetamine, and tobacco were shown to be the most harmful. Additionally, psychedelics have a very low risk of dependency and the lowest risk of lethality. There is complete dissonance between what recent studies show us and what society, and some doctors, think," said Roméo.

Besides these assumptions, another constraint to the use of psychedelics relates to methods adopted in related clinical studies. "Due to the effect psychedelics have, in the trials conducted, nine participants and nine doctors out of 10 are aware of what they have taken or given, respectively. This is a very important limitation. Nowadays, researchers don't know how to conduct accurate double-blind studies," said Roméo.

In sum, for psychiatrists, psychedelics are promising in addiction therapy, but healthcare professionals, public authorities, and society as a whole must be better informed about their use, and received ideas must be dispelled.

"The findings need to be replicated, but overall, psychedelics are really quite promising in treating both alcohol and tobacco use disorder. They are generally well-tolerated with few serious side effects. There is no deterioration in patients with psychiatric conditions while they are taking psychedelics. And if persistent symptoms of psychosis do occur, which is extremely rare, it's probably because there are preexisting underlying issues at play. We also don't see increased blood pressure or any other serious physical anomalies. In a supervised setting, as is the case with studies involving psychotherapeutic support, we can no longer say, in this day and age, that psychedelics are harmful," said Roméo.

Roméo reported no conflicts of interest regarding the content of this article.


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