A new review suggests psychedelic treatments may help people with obsessive-compulsive disorder (OCD), while cannabis appears to offer 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 with standard therapies such as SSRIs and behavioural treatment.
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 said the difference may lie 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 is overactive in OCD, while cannabinoids mainly target receptors associated with anxiety and compulsions without producing long-term symptom relief.
Researchers also noted that psychedelic trials typically include structured therapeutic support, encouraging patients to reflect on their experiences, which may contribute to better outcomes. Early clinical trial results show psilocybin can reduce OCD symptoms and help patients gain insight into their need for control, a core feature of the disorder.
The authors stressed that while the findings are encouraging, more rigorous research is needed. They also warned that psychedelics are not a cure-all and that reducing global barriers to research, including legal restrictions, remains essential.
