Psychedelic experiences linked to long-term improvements in psychological flexibility, study finds

A new study published in the Journal of Psychoactive Drugs suggests that psychedelic experiences—particularly those involving intense mystical elements—may lead to sustained improvements in psychological flexibility. People who reported such experiences, especially those using substances like ayahuasca or psilocybin with therapeutic or self-exploratory intent, tended to show greater increases in their ability to adapt to challenging thoughts and emotions over time.

Psychological flexibility refers to the ability to remain open to internal experiences, such as distressing thoughts or feelings, while acting in ways that align with personal values. It’s a central concept in acceptance-based therapies like Acceptance and Commitment Therapy (ACT) and is increasingly seen as a key pathway to mental well-being. Researchers have long theorized that psychedelics might help shift rigid thinking patterns, and psychological flexibility is one lens through which to understand how these changes might happen.

“This research topic was inspired by our previous results in participants who smoke tobacco, use cannabis, or consume alcohol,” said study author Bruno Romeo of Paul Brousse Hospital and the Université Paris-Saclay. “In those earlier studies, we found a link between psychological flexibility and a reduction in various types of substance use. Therefore, we wanted to explore which factors could influence psychological flexibility in our participants, which led us to conduct the present study.”

The researchers conducted a retrospective online survey involving 403 French adults who had undergone a personally significant psychedelic experience more than six months prior to participation. The study drew on data from three earlier surveys targeting different user groups—smokers, alcohol users, and cannabis users. Participants were asked to evaluate their psychological flexibility using the Acceptance and Action Questionnaire (AAQ-II) at three points in time: before the psychedelic experience, one month afterward, and during the six months leading up to the survey. They also completed the Mystical Experience Questionnaire (MEQ-30), which measured the intensity of the altered states they experienced.

Participants in the study used a range of substances, with LSD (57.1%) and psilocybin (30%) being the most common. Smaller numbers had used ayahuasca, DMT, or mescaline. Their motivations for taking psychedelics varied: 40% reported recreational reasons, while others cited psychological self-exploration (24.3%), curiosity (16.6%), therapeutic reasons (7.4%), or spiritual pursuits (5%).

On average, participants’ psychological flexibility scores improved after their psychedelic experience. Baseline scores averaged 44.2 on the AAQ-II, rising to 48.3 one month afterward and 49.5 over the prior six months—indicating a significant and lasting increase. Statistical analysis confirmed that these changes were unlikely due to chance.

The most consistent predictor of improvement was the intensity of the mystical experience during the trip. Participants who scored above the threshold for a “full mystical experience” on the MEQ-30 showed significantly greater increases in flexibility than those who did not. For example, one month after the experience, people who had a full mystical experience scored about four points higher on the AAQ-II than those who had less intense experiences. This association held even six months later.

The researchers also found that the starting level of psychological flexibility mattered. People who had lower flexibility before the psychedelic experience were more likely to show large improvements afterward. This may reflect a greater room for growth or a higher potential for change in those who begin with more rigid psychological patterns.

The type of psychedelic substance also played a role. Ayahuasca users experienced greater increases in psychological flexibility one month after the experience compared to LSD users. Frequent users—those who had used psychedelics dozens of times—also tended to score higher on psychological flexibility, but the direction of this relationship is unclear. It could reflect ongoing self-development efforts, or it might indicate that people with more flexible mindsets are more likely to continue using psychedelics.

Intent also influenced outcomes. People who took psychedelics with a recreational intent showed smaller improvements in psychological flexibility compared to those who used them for self-exploration or therapeutic reasons. This finding highlights the importance of mindset and context, sometimes referred to as “set and setting,” in shaping the psychological impact of psychedelics.

Interestingly, subjective dose did not significantly affect changes in flexibility. Participants were asked to categorize their dosage as very low, low, standard, high, or very high. These estimates, while useful, may not accurately reflect the pharmacological potency of the experience, especially given the uncontrolled and retrospective nature of the study.

To understand which factors best predicted long-term changes in psychological flexibility, the researchers ran multiple linear regression models. The two strongest predictors were the intensity of the mystical experience and the person’s initial level of psychological flexibility. Specific substances like psilocybin, mescaline, and ayahuasca, as well as higher frequency of use, were also linked to greater improvements.

“The mains key takeaways are: 1.) Intensity of mystical experience is associated with improvements in psychological flexibility, 2.) Lower baseline psychological flexibility is associated with subsequent improvements, and 3.) Frequents psychedelic use is correlates with improvements in psychological flexibility,” Romeo told PsyPost.

The findings add to a growing body of research suggesting that psychedelics may help shift mental habits and increase openness to experience. One explanation centers on the brain’s serotonin system, particularly the 5-HT2A receptor. Activation of this receptor is believed to play a key role in generating the altered states of consciousness associated with psychedelics. This same mechanism may also enhance neural plasticity—the brain’s ability to form new connections—which could underlie the changes in psychological flexibility.

Another possibility is that the mystical or meaningful quality of the experience itself leads to shifts in perspective. This might help people let go of avoidant or rigid ways of thinking, especially when those patterns are linked to mental health difficulties like depression or anxiety. But the authors caution that the relationship between mystical experiences and therapeutic outcomes may be more complex than it appears and might involve multiple interacting mechanisms.

There are several important limitations to keep in mind. This was a retrospective study, relying on participants’ memories of their experiences and their mental states at different points in time. This introduces the possibility of recall bias and makes it difficult to establish causal relationships. The self-selected sample, recruited online from psychedelic advocacy networks, may not be representative of the broader population. In addition, the use of self-reported dosing and the lack of control over substance purity and composition reduce the precision of the findings.

Despite these limitations, the study provides important new insights into the potential of psychedelics to support psychological change. It suggests that people who undergo intense, meaningful psychedelic experiences—especially with a self-reflective or therapeutic mindset—may gain lasting benefits in their ability to adapt and respond to life’s challenges.

“The next step in our research is to conduct a prospective study to confirm our initial results,” Romeo said. “Following that, we aim to explore correlations with biological variables that could help explain the mechanisms of action of these molecules.”

The study, “Exploring Factors Affecting Psychological Flexibility After Psychedelic Experiences,” was authored by B. Romeo, E. Kervadec, B. Fauvel, L. Strika-Bruneau, A. Amirouche, V. Verroust, P. Piolino, and A. Benyamina.