Psilocybin significantly decreased symptoms of OCD after 8 weeks

Key takeaways:

• The study included 15 adults with severe OCD symptoms.
• At 1 week follow-up after end of dosing, 80% of participants had a symptom reduction of 25%, with 40% in remission.

MIAMI BEACH, Fla. —Treatment with psilocybin significantly reduced symptoms at 8 weeks in patients with severe obsessive-compulsive disorder, according to a poster at the American Society of Clinical Psychopharmacology annual meeting.

“We were trying to treat a population that is very hard to treat, with an alternative treatment that is under-researched,” Katja Ehrmann Allen, of the department of psychology and psychiatry at the University of Arizona, told Healio.

As previous research has reported on the beneficial effects of hallucinogenic drugs for hard-to-treat psychological issues such as obsessive-compulsive disorder, Allen and colleagues sought to assess effectiveness of psilocybin in a small cohort of adults with moderate to severe OCD, many of whom are prescribed medication.

Their study included 15 participants (mean age, 38.1 years; 86.6% white) with severe OCD who had limited previous experience with psychedelics. A screening period introduced the Yale-Brown Obsessive Compulsive Scale (Y-BOCS), which rated severity of OCD symptoms in participants ahead of the initial study phase with participants randomized to receive either 100 micrograms per kg of psilocybin, 300 micrograms/kg or 1 mg lorazepam for 4 weeks. The second phase involved administering the high dose of 300 micrograms/kg to all participants for weeks 5 through 8 before a follow-up at 6 months.

Results showed that psilocybin significantly reduced symptoms of OCD compared with lorazepam at week 4, while Y-BOCS scores were significantly reduced from baseline at week 8. One week after the final dosing session, 80% of participants responded with symptom reduction of 25% or more from baseline, while 40% were remitted.

Researchers found that after 6 months, 20% of participants remained in remission, and 66.7% demonstrated symptom reduction of 25% or more with a causal relationship between number of doses and symptom reduction.

Psilocybin was well-tolerated, with no increase in suicidality or emergence of psychotic symptoms in the patient population. No severe adverse events were observed, with no observable difference among the three treatment groups with regard to minimal, mild or moderate adverse events, Allen and colleagues wrote.

“We’re getting much better results treating people with psilocybin than with any other treatment at this point,” Allen said.