Mystical but Not Challenging Experiences Predict Symptom Improvement After Psilocybin for Treatment-Resistant OCD
Sarah Shnayder, Gabrielle Agin-Liebes, Troy Hubert, Terence H. W. Ching, Jamila Hokanson, Christopher Pittenger, Benjamin Kelmendi, Thomas G. Adams
February 11, 2026 preprint DOI: 10.31234/osf.io/d94hb_v1 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Exploratory analysis of data from a randomized, double-blind, placebo-controlled trial and subsequent open-label phase |
|---|---|
| Sample size | 27 |
| Population | Participants with treatment-resistant obsessive-compulsive disorder (OCD) |
| Intervention | Psilocybin |
| Dose | 0.25 mg/kg |
| Duration | Single dosing session with 1- and 12-week follow-up |
| Topics | Anxiety Psilocybin Mystical experience |
| Keywords | Obsessive compulsive Mood Exploratory research Clinical trial Severity of illness Hallucinogen Clinical psychology Psychotherapist Anhedonia Depressive symptoms Depression economics |
| Key findings | Greater mystical-type experiences during psilocybin sessions were associated with lower OCD symptom severity at 1- and 12-week follow-up. |
Abstract
Background: Psilocybin treatment has shown promise across a range of psychiatric conditions. Mystical-type experiences during dosing sessions have been shown to predict the clinical effects of psilocybin treatment in depression, anxiety, and addiction. However, no studies have examined whether acute subjective experiences predict treatment response in obsessive-compulsive disorder (OCD).
Methods: Exploratory analyses were conducted using data from participants with treatment-resistant OCD who received psilocybin as part of a randomized, double-blind, placebo-controlled trial and subsequent open-label phase. Twenty-seven participants who received psilocybin (0.25 mg/kg) completed the Mystical Experience Questionnaire (MEQ) and Challenging Experience Questionnaire (CEQ) the day following their session. OCD severity was assessed using the Yale-Brown Obsessive Compulsive Scale (Y-BOCS) at baseline and at 1- and 12-week follow-up.Results: Greater mystical-type experiences during psilocybin were associated with lower OCD symptom severity at 1- and 12-week follow-up, even after controlling for baseline OCD symptom severity and treatment condition. The Mystical subscale demonstrated the strongest and most consistent associations at both time points, while the Space–Time subscale was only associated with lower Y-BOCS at 12 weeks. The Positive Mood and Ineffability subscales were not significantly associated with post-treatment OCD symptom severity after correction for multiple comparisons. Challenging experiences were not significantly associated with post-treatment OCD severity.
Conclusions: Mystical experiences – particularly experiences of unity, sacredness, and transcendence – during psilocybin sessions are associated with greater OCD symptom reduction. These findings support attention to experiential quality in psilocybin-assisted therapy and have implications for optimizing treatment through dosing, set, setting, and integration practices.