Grob · Archives of general psychiatry 2011 · randomized double-blind placebo-controlled crossover trial · n=12

Pilot study of psilocybin treatment for anxiety in patients with advanced-stage cancer.

Cited 1233 times in the scientific literature.

Level 2 - randomized trial

Individual double-blind, placebo-controlled trial with within-subject control

PubMed 20819978 · doi:10.1001/archgenpsychiatry.2010.116 · record verified 2026-08-30

What was done

A double-blind, placebo-controlled study evaluated a moderate dose of psilocybin (0.2 mg/kg) in 12 adults with advanced-stage cancer and reactive anxiety, with subjects acting as their own control. Safety and subjective experiences were monitored during treatment sessions, and follow-up data (State-Trait Anxiety Inventory, Beck Depression Inventory, Profile of Mood States) were collected unblinded over 6 months.

What was found

The abstract reports no raw numerical scores or effect sizes. It reports that psilocybin produced safe physiological and psychological responses with no clinically significant adverse events, significantly reduced STAI trait anxiety at 1 and 3 months, significantly improved BDI depression scores at 6 months, and led to POMS mood improvements that approached but did not reach statistical significance.

Why it matters

This pilot study demonstrated the feasibility and safety of psilocybin for existential distress in advanced cancer, helping reopen clinical psychedelic research.

Limits

The sample size was very small (n=12), the 6-month follow-up assessments were unblinded, and the abstract omits exact point estimates, variance, and p-values.

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