Pilot study of the 5-HT2AR agonist psilocybin in the treatment of tobacco addiction

This is the first study (and still one of the few) to use psilocybin and cognitive behavioral therapy (CBT) in concert for smoking cessation. 80% of participants, in the open-label study, were smoking-free after 6 months.


“Despite suggestive early findings on the therapeutic use of hallucinogens in the treatment of substance use disorders, rigorous follow-up has not been conducted. To determine the safety and feasibility of psilocybin as an adjunct to tobacco smoking cessation treatment we conducted an openlabel pilot study administering moderate (20 mg/70 kg) and high (30 mg/70 kg) doses of psilocybin within a structured 15-week smoking cessation treatment protocol. Participants were 15 psychiatrically healthy nicotine-dependent smokers (10 males; mean age of 51 years), with a mean of six previous lifetime quit attempts, and smoking a mean of 19 cigarettes per day for a mean of 31 years at intake. Biomarkers assessing smoking status, and self-report measures of smoking behavior demonstrated that 12 of 15 participants (80%) showed seven-day point prevalence abstinence at 6-month follow-up. The observed smoking cessation rate substantially exceeds rates commonly reported for other behavioral and/or pharmacological therapies (typically <35%). Although the open-label design does not allow for definitive conclusions regarding the efficacy of psilocybin, these findings suggest psilocybin may be a potentially efficacious adjunct to current smoking cessation treatment models. The present study illustrates a framework for future research on the efficacy and mechanisms of hallucinogen-facilitated treatment of addiction..”

Authors: Matthew W. Johnson, Albert Garcia-Romeu, Mary P. Cosimano & Roland R. Griffiths


  • Fist study on the use of psilocybin for tobacco addiction (smoking)
  • 80% still weren’t smoking after 6 months (vs <35% for other interventions)
  • A positive sign that psilocybin may be used for smoking cessation, but little follow-up studies in this area

This paper is followed up by qualitative and long-term follow-ups by Johnson, Garcia-Romeu & Griffiths (2016) and Noorani et al. (2018).

It also is followed-up by an analysis of the music used by Strickland, Garcia-Romeu & Johnson (2020).

Another follow-up study by Garcia-Romeu and colleagues (2014) looked specifically at the mystical experience, which was higher in those who quit smoking.

A survey study of people who (fully/partially/temporarily) stopped smoking after psychedelic use was done by Johnson and colleagues (2017) which showed similar large and positive results.

As it was the first study with psilocybin for smoking cessation, the goal was to test safety, feasibility, and give the first indication of efficacy. The study also highlights possible improvements and updates for future research.

“Based on the Timeline Follow-back and verified by CO and cotinine measures, 12 of 15 (80%) participants showed seven-day point prevalence abstinence at 6-month follow-up”.

Of those that did continue smoking, the daily total was significantly reduced (from 20 to 14 per day).

“Smoking-related mortalities in the USA are currently estimated at 480,000 annually (US Department of Health and Human Services, 2014), and 5 million annually worldwide (World Health Organization, 2011).”

Although there isn’t much follow-up (yet) to this study, and the protocols need to be refined, the problem that it’s tackling is far from insignificant. Also, the 80% stopping rate versus the typical 35% or less is quite significant.

“[L]ong-term abstinence may be enhanced by including multiple sessions, which may work by extending the β€œafterglow” period through the time of greatest relapse risk, or by increasing the probability of a transformative mystical experience.”

Multiple sessions may make it easier to get over the relapse period.

The participants had many moments of contact with the researchers/therapists:

  • 90 min x4 preparatory meetings
  • 8 hours session (x2 or x3)
  • 60 min x1 after a session (x2 or x3)
  • 45 min x10 support meetings
  • 5 min x14 daily phone call

Cognitive-behavioral therapy (CBT) was part of the preparatory meetings. During the session there was no active therapy, just like with other studies the participants were directed inward and listened to music.

“Eleven (73%) rated at least one psilocybin session among the five most spiritually significant experiences of their lives, and 13 (87%) reported that their personal well-being or life satisfaction had increased very much as a result of at least one psilocybin session.”

In line with earlier research (e.g. Griffiths et al., 2008), this paper again shows how significant the sessions were to participants.

“However, the mechanistic role of psilocybin in smoking cessation remains unclear. Participant responses in the present study suggest that increased temporal horizon, increased self-efficacy, and altered life priorities may be involved.”

In the final discussion, the authors note that we don’t know exactly what is it in the psilocybin-assisted session that helps people stop smoking. This is, of course, something that will be readily studied in the coming years.

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