A new review suggests that psychedelic treatments such as psilocybin may help reduce symptoms of obsessive-compulsive disorder (OCD), while cannabis-based treatments show little lasting benefit.
The review, led by Dr Michael Van Ameringen of McMaster University and published in the Journal of Psychiatric Research, examined existing evidence on alternative treatments for OCD. It found stronger signals of effectiveness for psychedelics, particularly psilocybin, than for cannabinoids like THC and CBD.
Researchers believe the difference lies in how the substances affect the brain. Psilocybin appears to reduce activity in the brain’s default mode network, which is linked to rumination and intrusive thinking common in OCD. Cannabis, while it can reduce anxiety and compulsions in the short term, has not been shown to produce sustained symptom improvement.
Preliminary clinical trials included in the review showed that a single dose of psilocybin improved OCD symptoms compared with placebo. Researchers caution that further large-scale, controlled studies are needed, and stress that reducing global stigma and legal barriers around psychedelic research remains essential.
