New research provides evidence that a single psilocybin dose can result in long-term increases in mindfulness, even in the absence of explicit mindfulness training. The study, published in European Neuropsychopharmacology, suggests that these changes in mindfulness are related to changes in the serotonin 2A receptor, one of the 14 serotonin receptors in the brain.

Psilocybin is a powerful psychedelic drug and the active ingredient in so-called “magic mushrooms.”

“Psilocybin is being intensely studied by both the pharmaceutical industry and academic institutions, and most published studies suggest that psilocybin therapy may be very beneficial for a number of psychiatric disorders,” said Martin Korsbak Madsen, the corresponding author of the study and a PhD student at the University of Copenhagen.

“Our Neurobiology Research unit has for years been at the forefront of mapping the brain’s serotonin system using positron emission tomography (PET) brain imaging. Now, psilocybin acts by stimulating the brain’s serotonin 2A receptors, and since we developed a very good serotonin 2A PET imaging radiotracer in our lab, the need to understand if psilocybin affect the serotonin 2A receptors in the brain converged nicely with our PET imaging expertise.”

Ten healthy volunteers without prior experience with psychedelic drugs completed assessments of mindfulness, personality, and other factors before undergoing a neuroimaging session. On another day, the volunteers received a dose of psilocybin and then listened to a standardized music playlist. Eight of the ten volunteers had a “complete mystical experience” based on the Altered States of Consciousness questionnaire.

One week later, the volunteers again underwent neuroimaging and, three months later, the volunteers again completed assessments of mindfulness, personality, and other long-term effects.

The researchers found that the volunteers’ levels of mindfulness and openness tended to increase from baseline to the follow-up. In other words, the participants became less likely to agree with statements such as “I find it difficult to stay focused on what’s happening in the present” and “I do jobs or tasks automatically, without being aware of what I’m doing.”

Changes in serotonin 2A receptor binding after one week were also negatively correlated with changes in mindfulness three months after the psilocybin session.

“Psilocybin seems to increase mindful awareness in a long-term fashion in people who have never tried a psychedelic drug. Our results also show that subtle changes in brain serotonin 2A receptor levels and/or the serotonin levels probably contributes to these changes,” Madsen told PsyPost.

The volunteers also reported that the psilocybin session had resulted in long-term enhancements in mood, spirituality and outlook on life.

“Our results are in line with much anecdotal evidence and are in line with a recent study from Switzerland, which found that psilocybin boosted the mindfulness enhancing effect of an intensive mindfulness retreat,” Madsen added.

“It is striking that we found a large long-term mindfulness increase without any mindfulness training in healthy individuals, and it is likely that this effect — the increase in mindfulness — also happens in patients and is important for clinical response.”

But — like all research — the study includes some limitations. “Most importantly, our results should be replicated in a larger sample and in a double-blind study using a placebo control,” Madsen said.

The study, “A single psilocybin dose is associated with long-term increased mindfulness, preceded by a proportional change in neocortical 5-HT2A receptor binding“, was authored by Martin Korsbak Madsen, Patrick MacDonald Fisher, Dea Siggaard Stenbæk, Sara Kristiansen, Daniel Burmester, Szabolcs Lehel, Tomas Páleníček, Martin Kuchar, Claus Svarer, Brice Ozenne, and Gitte M. Knudsen.