7-Day Meditation Retreat Triggers Psychedelic-Like Brain Changes in 20 Adults

3 articles · Updated · ScienceAlert · Aug 11

Twenty adults in a seven-day San Diego meditation retreat showed reduced activity in the brain’s default mode and salience networks, alongside higher mystical-experience scores that researchers said resembled psychedelic effects.
fMRI scans, blood tests and questionnaires taken before and after the retreat pointed to broader biological shifts, including more efficient whole-brain information flow, immune modulation and higher endogenous opioids.
Post-retreat blood plasma also made neurons in a dish grow longer neurites, suggesting possible neuroplasticity-related effects after the program’s guided meditation, lectures and group healing rituals.
MEQ-30 scores rose to 3.02 from 2.37, but the 2025 Communications Biology study was observational, lacked a control group and involved a co-author whose company hosts the retreats.
Researchers said the findings add to evidence that meditation can reshape brain activity, while calling for larger controlled studies to test whether the retreat itself caused the changes.