Psychiatrist and researcher Dr. Mary Lynch is exploring an illegal substance that shows great promise for controlling symptoms of neuropathic pain: marijuana. Cannabis, marijuana's more technical name, traditionally has been the focus of very little research within Canada, and is rarely mentioned in Canadian medical literature.
"Everyday we saw patients who were struggling with severe neuropathic pain," says the director of research at the pain management clinic at the QEII Health Sciences Centre. "Even when we did everything we could, we were still often in the sorry position of having to tell them, 'You will simply have to go home and live with this.' To me as a clinician, that was unsatisfactory."
Dr. Lynch began exploring alternatives such as topical applications. Given that chronic pain is often caused by abnormal processing of sensory information, and that local sensory nerves, such as those in the skin, are involved in transmitting pain messages, she believes topical approaches are worth investigating. "This approach is also exciting because the medication stays at the receptors," she says. Given its toxic side effects, "we don't want it to be actually absorbed into the bloodstream. Yet we've learned from our own studies as well as the studies of others that such topical approaches are actually effective."
Then, in the 1990s, she started considering cannabis after her patients began confiding in her that they'd been using the plant for symptom control, and that it did a better job than anything else her pain management clinic had tried.
At the same time, the Canadian Institutes of Health Research (CIHR) were looking for proposals for new interdisciplinary research teams wanting to try new approaches. Dr. Lynch applied for and received funding to set up an organization to research the potential role of cannabinoids, in pill or injectable form, in controlling neuropathic pain.
In early 2000, Dr. Lynch brought together 26 top researchers from across Canada to form the Canadian Consortium for the Investigation of Cannabinoids in Human Therapeutics. CCIC, which she heads, has been educating the federal government about cannabinoids as painkillers, and helping Health Canada develop other cannabis research initiatives.
Since cannabis is illegal, any research involving its use must go through additional regulatory approvals, "with more hoops to jump though," Dr. Lynch says. Despite this delay, CCIC has completed two survey studies investigating patients' use of cannabis. These studies targeted patients from the pain management unit and the multiple sclerosis unit.
They've found as a result that 10% to 14% of these patients use cannabis for symptom control, as compared with 5% in the general Canadian population. Furthermore, cannabis turns out to measurably help reduce neuropathic pain. CCIC also reviewed pre-clinical research on animals, which provided more evidence that cannabis is a powerful analgesic.