There is no strong evidence to back a licensed cannabis-extract medicine which the Department of Health plans to make available to multiple sclerosis patients next year, according to a study. The drug, Sativex, is used in the treatment of muscle spasms in sufferers of the disease. According to the study's findings, the strength of any evidence is insufficient to warrant its routine use.

In addition, a change in the law will be needed here before doctors are allowed to prescribe it for patients. The study, led by Dr James Cave, editor of the 'Drugs and Therapeutic Bulletin' (DTB), which is part of the British Medical Journal group, examined the effects of the drug – given in the form of a mouth spray – which contained the extracts dronabinol and cannabidiol from the cannabis plant....