Smoking cannabis reduces chronic pain with damaged nerves and improves sleep with anxiety.
Around 1 to 2% of people have chronic neuropathic pain due to problems with signalling between nerves but effective treatments are lacking. Some patients with this type of chronic pain suggest that smoking cannabis helps symptoms. McGill University in Montreal suggests that clinical trials on smoked cannabis were lacking.
The study used three different potencies of cannabis - containing 2.5%, 6% and 9.4% of the active ingredient tetrahydrocannabinol. Those given the highest dose had significantly reduced average pain compared with the placebo, less anxiety and depression and improved sleep quality.
Study leader Dr Mark Ware said this is the first outpatient clinical trial of smoked cannabis reported. Prof Tony Dickenson, an expert in pain medicine at University College London, said numerous patients with pain say they benefit from cannabis but there were clearly health issues associated with self-medicating in this way and said that the pain relief seen was quite small but could make an important difference to patients who suffer sleeplessness and depression.
Dr Peter Shortland, a senior lecturer in neuroscience at Barts and The London School of Medicine and Dentistry said ‘Importantly, smoking the drug did not produce the psychoactive effects commonly associated with full strength cannabis’ adding that the trial was ‘an encouraging step forward’ but further clinical trials are warranted.