Lasting increases in trait mindfulness after psilocybin correlate positively with the mystical-type experience in healthy individuals

This open-label study (n=39) assessed the association between psilocybin lasting increases in trait mindfulness and the mystical-type experience using the Mystical Experience Questionnaire (MEQ). The MEQ was administered after psilocybin sessions (16-22mg/70kg), and mindfulness was measured three months post-session using the Mindful Attention and Awareness Scale (MAAS). MAAS score was significantly increased at the 3-month follow-up. It was positively associated with the MEQ score (p = 0.035), indicating that the phenomenology of the psilocybin experience induces a shift toward mindful living.

Abstract

“Background: Psilocybin-induced mystical-type experiences are associated with lasting positive psychological outcomes. Recent studies indicate that trait mindfulness is increased 3 months after psilocybin intake, preceded by decreases in neocortical serotonin 2A receptor (5-HT_2AR) binding. However, the association between psilocybin-induced mystical-type experiences and subsequent changes in trait mindfulness remains unexplored, as does the association between pre-drug trait mindfulness and 5-HT_2AR binding in the healthy brain.

Aim: We evaluated whether psilocybin induced lasting increases in trait mindfulness in healthy volunteers, and whether the mystical-type experience was associated with this increase. We further examined the association between pre-drug trait mindfulness and 5-HT_2AR binding in neocortex and selected frontolimbic regions.

Materials and methods: Forty-six medium-high dose psilocybin sessions were conducted in 39 healthy individuals. The mystical-type experience was measured with the Mystical Experience Questionnaire (MEQ) at the end of the session. Trait mindfulness was measured using the Mindful Attention and Awareness Scale (MAAS) at baseline and 3 months after the psilocybin session. Thirty-two of the participants completed pre-drug [¹¹C]-Cimbi-36 positron emission tomography (PET) to assess 5-HT_2AR binding in neocortex and, post-hoc, in the frontolimbic regions amygdala, frontal cortex, and anterior cingulate cortex.

Results: The MAAS score was significantly increased at 3-month follow-up (p = 3.24 × 10^–6), a change positively associated with the MEQ score (p = 0.035). Although the association between pre-drug MAAS score and neocortex 5-HT_2AR binding was not significant (p = 0.24), post-hoc analyses revealed a significant negative association between MAAS and right amygdala 5-HT_2AR binding (p_FWER = 0.008).

Conclusion: We here show that lasting changes in trait mindfulness following psilocybin administration are positively associated with intensity of the mystical-type experience, suggesting that the acute phenomenology of psilocybin facilitates a shift in awareness conducive for mindful living. We furthermore show that higher pre-drug trait mindfulness is associated with reduced 5-HT_2AR binding in the right amygdala.”

Authors: Anna Soendergaard, Martin K. Madsen, Brice Ozenne, Sophia Armand, Gitte M. Knudsen, Partick M. Fisher & Dea S. Stenbaek