In psychedelic therapy, clinician-patient bond may matter most: Study links therapeutic alliance with reduced depression after psilocybin therapy

Psychological therapy alliance may be a key driver of long-term improvement in psilocybin-assisted treatment for major depressive disorder. Data from a 2021 clinical trial were reanalyzed, using depression outcomes and participant reports about both their psilocybin experiences and their connection to therapists. Participants received two doses of psilocybin alongside 11 hours of psychotherapy, and therapeutic alliance was measured after preparation and after each dosing session. Stronger therapeutic alliance scores were associated with lower depression scores up to one year later, with long-term effects persisting most clearly for the clinician-participant relationship. Acute mystical or psychologically insightful experiences related to short-term depression changes at four weeks, but mystical experiences were not linked to depression at 12 months. Authors frame the findings as evidence that psychedelic-assisted therapy depends heavily on trust and rapport to support safety and optimize outcomes. The study was published in PLOS ONE (2024) and reported support from multiple research funders including Ohio State-affiliated centers.