Posted 05.15.2019 | by AMRA

There are certain similarities between the increased awareness associated with the practice of mindfulness and the expanded consciousness associated with the use of psychedelic substances. Both are capable of promoting states of self-transcendence in which the boundary between one’s self and the world is erased, leading to a boundless sense of connection with the universe.

Smigielski et al. [Neuroimage] experimentally tested the effects of psilocybin, a psychedelic mushroom plant derivative, on self-reported, neurological, and behavioral outcomes among experienced meditators attending a meditation retreat.

The researchers randomly assigned 38 experienced meditators (average meditation experience = 5,000 hours; 61% male; average age = 52 years) on a five-day Zen meditation retreat to a psilocybin or placebo control condition. On the morning of the fourth retreat day, participants were administered either psilocybin (315 μgs/kg) or a placebo (lactose), and continued on with the regular retreat schedule. The research participants and assessors were blinded to the study group assignment.

Six hours after psilocybin or placebo administration, participants completed a questionnaire measuring psychological factors such as “oceanic self-boundlessness,” “dread of ego dissolution,” visual and auditory hallucinations, synesthesia, and “vigilance reduction.”

On the day before and after the retreat, participants underwent brain imaging (fMRI) to measure functional connectivity in the Default Mode Network (DMN) while resting, while engaging in focused attention meditation, and while engaging in open awareness meditation. The DMN is a network of brain regions that operates collectively when a person is simply resting and “doing nothing.”

DMN activity has been implicated in self-referential thinking, maintaining a unitary sense of identity, and maintaining the self-other boundary. Functional connectivity is a measure of the degree to which different brain regions are operationally integrated and display similar patterns of activation.

Four months after the retreat, participants completed a self-report measure of changes in attitudes towards self and the world, as well as changes in mood, social functioning, behavior, and spirituality.

The fMRI results showed that the psilocybin group displayed a significantly greater decrease in functional connectivity between two parts of the DMN—the medial prefrontal cortex (mPFC) and the posterior cingulate cortex (PCC)—from pre- to post-test while engaging in open awareness meditation than did the placebo group. Greater decreases in functional connectivity between these brain structures were strongly associated with more profound experiences of oceanic self-boundlessness during drug administration (r = -.60).

Four months later, the psilocybin group reported significantly more positive changes in attitude, mood, and behavior (2.58 points on a 6-point global positive effects scale) than did controls (0.65 points). These persisting positive effects correlated with the magnitude of oceanic self-boundlessness experienced during drug administration (r = .66).

Positive changes in attitude, mood, social functioning, behavior, and spirituality were associated with pre-to-post increases in connectivity between the mPFC and PCC while at rest, as well as with decreases between the mPFC and the right angular gyrus during focused attention. There were no adverse effects reported in either group.

This study shows that experienced meditators’ psilocybin-induced self-transcendent experiences are associated with a persistent improvement in their psychological sense of well-being. These self-transcendent experiences are also associated with functional changes in the brain which point to the DMN’s critical role in both self-reference and self-transcendence.

The study is limited by its small sample size. The researchers caution that the results may only apply to experienced meditators, a cohort that has engaged in extensive mental training. The study did not track the persistence of DMN functional connectivity changes in the follow-up period.


Smigielski, L., Scheidegger, M., Kometer, M., & Vollenweider, F. X. (2019). Psilocybin-assisted mindfulness training modulates self-consciousness and brain default mode network connectivity with lasting effects. NeuroImage.

[Link to study]