Largest Study of Medical Cannabis in Patients With OCD Finds ‘Substantial Improvements’

A new UK study highlights how medical cannabis may improve quality of life for people living with obsessive compulsive disorder (OCD). 

Researchers at Drug Science analysed data from what they believe to be the largest sample of OCD patients receiving cannabis-based medicines on prescription.

OCD is estimated to affect around 1-3% of the population in their lifetime and is often characterised by obsessive intrusive thoughts and compulsive behaviours. Many people will also experience symptoms such as anxiety, low mood and problems sleeping which cross-over with those of other mental health conditions.

Current treatments include talking therapies such as cognitive-behavioural therapy, and sometimes medication, but these are not always effective or well-tolerated. 

The researchers analysed data from over 200 patients who were receiving cannabis-based medicines on prescription from private clinics in the UK. Participants were prescribed an average of 2.2 cannabis products, with nearly three-quarters using THC-dominant cannabis flowers.

After three months of treatment, participants experienced ‘substantial improvements’ in overall quality of life, general health, mood, depression, and sleep. Anxiety symptoms also reduced significantly among those who completed the Generalised Anxiety Disorder (GAD-7) assessment.

Few adverse events were reported, with the majority assessed as mild.

“To the best of our knowledge, this is the largest sample of OCD patients receiving access to CBMPs under medical supervision,” the authors say.

“However, the evidence of quite substantial improvements in quality of life, possibly mediated by a reduction in OCD symptomatology, is consistent with a growing number of case reports and observational research documenting the health benefits of cannabis for people with OCD.”

The authors have called for further research, including clinical trials, to determine who might benefit most from cannabis-based treatments and to ensure they are used safely and effectively for patients with OCD. 

“Increasing numbers of people are receiving access to unlicensed medicinal cannabis both in the UK and internationally despite relatively little evidence from RCTs supporting the efficacy of these drugs,” they conclude.

“In addition to research assessing which cannabis-based medicines are most likely to be effective for specific conditions, real-world evidence can be used to determine the optimal strategy for providing access to these drugs in an equitable and efficient manner.”