Researchers from the University of Bath's Centre for Pain Research have contributed to a major international review into the safety and efficacy of cannabinoids when used to treat pain, including chronic pain in children and adults.

Conducted for the International Association for the Study of Pain (IASP) and recently published across 13 linked scientific articles in the journal Pain, leading experts from around the world including Dr. Fisher and Professor Eccleston from Bath reviewed existing data into cannabinoids, including for so-called 'medicinal cannabis' and 'medicinal cannabis extracts."

Their findings suggest that although there is preclinical data supporting the hypothesis of cannabinoid analgesia, uncertainties especially in clinical evidence, imply the evidence base for efficacy and safety does not reach the threshold required for the IASP to endorse their general use for pain control. The studies and the statement from the IASP are limited to the use of cannabinoids to treat pain, and not for other conditions for which cannabinoids are used.

Dr. Emma Fisher who led the review of the clinical evidence said: "Cannabis, cannabinoids, and cannabis-based medicines are becoming an increasingly popular alternative to manage pain. However, our review shows that there is limited evidence to support or refute their use for the management of any pain condition. The studies we found were poor quality (high risk of bias) and the evidence was of very low-certainty, meaning that we are very uncertain of the findings and more research is needed."

Professor Christopher Eccleston, Director of the Centre for Pain Research / Department for Health, said: "Cannabis seems to attract strong opinions. If ever a field needed evidence and a rigorous scientific opinion it is this one. For many this will be an unpopular conclusion, but we need to face up to the fact that the evidence is simply lacking. Science is not about popularity but keeping people safe from false claims. The challenge in this field will be for governments to fund independent research, and to ensure balance and equipoise.

"Coming close on the heels of The Lancet Commission on children's pain and the WHO guidelines on treating chronic pain, this further contribution also found no evidence to support the use of cannabis, cannabinoids, and cannabis-based medicines for children with chronic pain. We need to invest in real solutions to the very real problem of chronic pain in children."