A clinical review, published at the end of last week in the BMJ, provides new interim advice for healthcare professionals interested in prescribing cannabis-based products and cannabinoids to treat certain conditions.

This was authored by leading scientists and clinicians from the University of Bath and University College London (UCL) and points to huge range of cannabis-based products available, with a clear need to educate both patients and clinicians into what these different products do and how they might help.

In particular, it points to important differences between products containing THC (the main psychoactive and intoxicating element of cannabis) versus CBD (the non-intoxicating component). Although in certain medicines, these cannabinoids are combined for clinical benefit, in others these components work independently.

“In this complex and rapidly evolving field, there are several different cannabis-based and cannabinoid medicinal products,” says lead author, Dr Tom Freeman of the University of Bath's Addiction and Mental Health Group. “A key message is that CBD products widely sold online and in health food shops lack quality standards and should not be treated as medicinal products."

Research on cannabis was previously restricted because it was listed in Schedule 1, suggesting that it had no medical value. Cannabis was recently moved to Schedule 2 in the UK and will be the subject of an upcoming NICE review. "The rescheduling of cannabis and allocation of dedicated UK research funding will improve the evidence we have to guide clinical decision making," says Freeman.

"There have been leaps and bounds in our scientific knowledge in recent years, which combined with confusing claims about the medicinal uses of these drugs, can be potentially perplexing for doctors and patients,” says co-author, Dr Michael Bloomfield, head of Translational Psychiatry at University College London (UCL). “We hope that our new guidance is helpful to doctors and patients worldwide. Much more research is needed into this new class of medicine."

Authors also called for healthcare professionals to remain open-minded on the topic. “We would like to encourage doctors to maintain a compassionate and evidence-based approach when engaging with their patients in this rapidly developing field, in order to provide the best standard of care,” said co-author Dr Chandni Hindocha of the Clinical Psychopharmacology Unit at UCL.