A new review suggests psychedelic treatments such as psilocybin may help people with obsessive-compulsive disorder (OCD), while cannabis-based treatments show little evidence of benefit.
The review, published in the Journal of Psychiatric Research and led by Dr Michael Van Ameringen of McMaster University, examined existing research on alternative treatments for OCD. The condition affects about 2% of people and does not respond adequately to standard treatments in up to 60% of patients.
After analysing published studies, conference data and preliminary findings, the researchers found stronger evidence supporting psychedelics, particularly psilocybin, than cannabinoids like THC or CBD. Van Ameringen suggested the difference may be linked to how the substances affect the brain. Psilocybin appears to reduce activity in the brain’s default mode network, which is associated with rumination and is overactive in OCD, while cannabinoids do not seem to produce lasting symptom relief.
Early clinical trials indicate psilocybin may reduce OCD symptoms and help patients gain insight into compulsive patterns, though researchers stress that further large-scale studies are needed. Cannabis, by contrast, is more commonly used for short-term symptom relief and has not shown consistent therapeutic effects for OCD.
Despite the promising findings, researchers note that psilocybin remains illegal in many countries, making research difficult, and emphasise the need for cautious, rigorous study rather than hype.
