Obsessive-Compulsive Disorder

What the early signal showed

In a very small modified double-blind dose-ranging pilot, Moreno et al. (2006) observed marked acute decreases in Yale-Brown Obsessive Compulsive Scale scores after psilocybin. The finding has been influential because OCD symptoms are often slow to move under conventional care.

What is happening now

Two modern protocol papers expand the pipeline without yet establishing confirmatory efficacy:

• PsilOCD uses an active-controlled pharmacological challenge design with EEG and cognitive-flexibility endpoints.
• An open-label psilocybin-assisted psychotherapy pilot protocol targets treatment-resistant OCD feasibility and preliminary clinical effects.

Why this remains a candidate

• The classic Moreno sample was tiny and lacked a parallel placebo arm.
• Current documents are largely protocols rather than completed pivotal RCTs.
• Dose-response, durability, and therapist-model questions remain open.

Negative or mixed considerations

Not all obsessive or compulsive presentations will respond similarly. Acute intensification of intrusive content is theoretically possible during a session, so screening and monitoring standards matter as much as efficacy hopes.