Mystical but Not Challenging Experiences Predict Symptom Improvement After Psilocybin for Treatment-Resistant OCD
February 11, 2026 Sarah Shnayder, Gabrielle Agin-Liebes, Troy Hubert et al. preprint
In people with treatment-resistant obsessive-compulsive disorder (OCD), greater mystical-type experiences during psilocybin sessions—especially feelings of unity, sacredness, and transcendence—were linked to lower OCD symptom severity at 1-week and 12-week follow-ups, even after accounting for baseline severity and treatment condition. The Mystical subscale of the Mystical Experience Questionnaire showed the strongest and most consistent associations. The Space–Time subscale was related to lower OCD severity only at 12 weeks. Positive mood, ineffability, and challenging experiences were not significantly tied to post-treatment OCD severity. These results suggest that the quality of subjective experience during psilocybin sessions may help optimize treatment outcomes.