By Pat Anson, Editor

Chronic pain patients who use medical marijuana daily for a year suffered no serious side effects and significantly improved their levels of pain, mood and quality of life, according to a new study in Canada.

The clinical study by researchers at McGill University in Montreal is one of the first to test the long term safety and efficacy of medical marijuana. It’s been published online in the Journal of Pain, the official journal of the American Pain Society.

“Quality-controlled herbal cannabis, when used by cannabis-experienced patients as part of a monitored treatment program over one year, appears to have a reasonable safety profile,” wrote lead author Mark Ware, an associate professor in Family Medicine and Anesthesia at McGill University and one of the world’s leading experts on medical marijuana.

Pain News Network had a lengthy interview with Ware about his research earlier this year.

In his most recent study, Ware and his colleagues assessed the long-term health of 216 medical marijuana users with chronic non-cancer pain who consumed a standardized dose (12.5% THC) of up to 5 grams of marijuana daily through inhaling or vaporization. They were compared to a control group of 215 chronic pain sufferers who did not use marijuana. Both groups were monitored over the course of the one year study.

Researchers said the cannabis users had no serious side effects compared to the control group, and had a significant improvement in their pain, anxiety, depression, anger and fatigue.

“We noted significant improvements in pain intensity and the physical dimension of quality of life over one year among the cannabis users compared to controls; there was also significant improvement among cannabis users in measures of the sensory component of pain, symptom distress, and total mood disturbance compared to controls. These findings, while not the primary outcomes of the study, are nevertheless important in considering the overall risk-benefit ratio of medical use of cannabis,” Ware wrote.

“The results suggest that cannabis at average doses of 2.5g/d in current cannabis users may be safe as part of carefully monitored pain management program when conventional treatments have been considered medically inappropriate or inadequate.”

The marijuana group did report more non-serious side effects, such as headache, nausea,  dizziness, and respiratory problems associated with smoking.