A new review suggests psychedelic treatments, particularly psilocybin, may help reduce symptoms of obsessive-compulsive disorder (OCD), while cannabis shows little lasting benefit.
The review, led by Dr Michael Van Ameringen of McMaster University and published in the Journal of Psychiatric Research, examined alternative treatments for OCD, a condition in which up to 60% of patients see limited improvement from standard therapies. After analysing published studies, conference data and early trial results, the researchers found stronger evidence supporting psychedelics than cannabinoids such as THC and CBD.
Van Ameringen said the difference may lie in how the substances affect the brain. Cannabinoids act on CB1 receptors linked to anxiety and compulsive behaviour but do not appear to produce sustained symptom relief. Psilocybin, however, reduces activity in the brain’s default mode network, which is associated with rumination and is overactive in OCD.
Preliminary clinical trials have shown psilocybin can reduce OCD symptoms compared with placebo, while also helping patients gain insight into their need for control. Researchers cautioned that more rigorous studies are needed and stressed that psychedelics are not a cure. They also noted ongoing challenges, including legal restrictions and managing unrealistic expectations around psychedelic treatments.
