A new study published in the Journal of Psychoactive Drugs has found that psychedelic experiences are linked to reductions in cannabis use and improvements in psychological flexibility. Participants who reported a personally meaningful experience with a classic psychedelic, such as LSD or psilocybin, tended to show lower levels of problematic cannabis use afterward, and many also reported changes in how they relate to difficult thoughts and emotions. The findings suggest that naturalistic psychedelic experiences might influence substance use behaviors in a lasting way.
Cannabis use has increased considerably over the past decade. According to global data from 2020, more than 190 million people reported using cannabis in the previous year. As use becomes more common, so does the risk of developing cannabis use disorder, a condition that affects roughly one in ten users and is associated with significant challenges, including high relapse rates and few effective treatment options.
Currently, there are no approved medications for treating cannabis use disorder. Behavioral interventions can help, but their effects often do not last. Researchers are increasingly interested in whether psychedelics might offer a new path forward. Prior studies suggest potential benefits of psychedelics in treating tobacco and alcohol dependence. There is also some evidence that psychedelics might reduce cannabis use, but those earlier studies often relied on targeted sampling methods or did not explore changes in psychological functioning.
The new study sought to build on this early work by using a broader sample of cannabis users who had experienced a psychedelic trip that they considered personally significant. The researchers aimed to find out whether these experiences were followed by lasting changes in cannabis use and in psychological flexibility, a factor often associated with mental health and well-being.
“Cannabis use disorder is very common in the general population, and currently, there are no pharmacological treatments that have proven effective for this condition. Moreover, psychedelics have shown promising results in treating substance use disorders, but very few studies have investigated their effects on cannabis use disorder,” said study author Bruno Roméo of the Department of Psychiatry and Addictology at Paul Brousse Hospital and the PSYCOMADD research unit at Paris-Saclay University.
The researchers conducted an online retrospective survey between March and July 2023. Participants were recruited through the French Psychedelic Society’s website and social media. To be eligible, participants had to be at least 18 years old, fluent in French, have used cannabis, and report having had a significant psychedelic experience at least six months prior.
A total of 152 participants completed most or all of the survey. They were asked to recall their cannabis use before and after their psychedelic experience. They also completed standardized questionnaires measuring the severity of cannabis use problems, psychological flexibility, and the intensity of their psychedelic experience.
The majority of participants were men, with an average age of 36. Most described their chosen psychedelic experience as recreational or motivated by self-exploration. Common substances included LSD and psilocybin. Very few participants reported that their psychedelic experience was originally intended to help them stop using cannabis.
Despite this, the study found a significant decline in problematic cannabis use following the psychedelic experience. Scores on the Cannabis Use Disorder Identification Test dropped by about 38 percent from the baseline measurement to the six-month follow-up. These reductions were evident as early as one month after the experience and appeared to persist over time.
Cannabis use became less frequent, and the daily duration of intoxication also decreased. For example, the number of participants who met criteria for severe cannabis use disorder dropped from roughly 23 percent to about 9 percent over six months. Similarly, the proportion of participants who reported cannabis cravings and tolerance also declined.
At the same time, participants showed an increase in psychological flexibility, as measured by a validated self-report questionnaire. Psychological flexibility refers to a person’s ability to adapt to challenging situations, stay open to emotional experiences, and pursue meaningful goals even when facing discomfort. Scores on this measure rose significantly one month after the psychedelic experience and remained elevated six months later.
Another notable finding was the association between the intensity of the psychedelic experience and the reported changes. Participants who rated their experience as more intense on a mystical experience scale were more likely to report reductions in cannabis use and gains in psychological flexibility. These correlations suggest that the subjective nature of the experience might play a role in the observed changes.
However, when the researchers used a statistical model to predict who would reduce their cannabis use, they found that baseline severity was the strongest predictor. The intensity of the mystical experience and changes in psychological flexibility did not emerge as direct predictors in that model, though they remained correlated with change in other analyses.
“The main key takeaways: An association was found between naturalistic psychedelic use and a reduction in CUDIT scores, frequency of cannabis use, and the acute duration of daily intoxication,” Roméo told PsyPost. “Participants reported a concomitant increase in psychological flexibility following their psychedelic experiences, which was correlated with the intensity of the psychedelic experience.”
As with all research, there are limitations to consider. Because the research was retrospective and relied on self-reported memories, the results are subject to recall bias. Participants were asked to compare their current and past behavior based on memory, and the accuracy of these recollections cannot be verified.
There was no control group of individuals who had not taken psychedelics, making it difficult to determine whether the changes were directly caused by the psychedelic experience. Many other factors could explain the observed changes, such as life events, personal motivation, or broader shifts in cannabis use patterns.
“There is a major limitation, which is the retrospective design of our study,” Roméo said. “This design does not allow us to attribute potential causality to our results.”
The sample was also self-selected and recruited through a psychedelic interest group. People who had positive experiences with psychedelics may have been more likely to take part in the survey. This introduces the possibility of volunteer bias. It is also likely that participants chose to describe their most meaningful psychedelic experience rather than one at random, which could have inflated the apparent benefits.
Despite these limitations, the study sheds additional light on the relationship between psychedelic experience and substance use patterns, and highlights some areas for future exploration. The authors propose that a prospective study—where participants are followed over time starting before their psychedelic experience—could provide more conclusive evidence. They also suggest including therapeutic preparation and integration support, which are often used in clinical psychedelic trials, to better understand the role of context and psychological support.
The study, “Significant Psychedelic Experiences Evaluated for Mystical Characteristics Associated with Cannabis Use Reduction and Psychological Flexibility Improvement: A Naturalistic Cross-Sectional Retrospective Survey,” was authored by B. Romeo, E. Kervadec, B. Fauvel, L. Strika-Bruneau, A. Amirouche, V. Verroust, P. Piolino, and A. Benyamina.
