Many fibromyalgia patients are smoking marijuana or taking synthetic forms of cannabinoids to help relieve their pain, according to a Canadian study. But the researchers also found that marijuana use by fibromyalgia patients was also associated with unemployment, mental illness and opioid use.
“The cannabinoid system has known modulatory effects on pain, inflammation, immune function, and even joint damage,” wrote lead author Dr. Mary-Ann Fitzcharles, a professor of medicine at McGill Universityand consulting rheumatologist at Montreal General Hospital (MUHC) in Montreal, Canada. “While self-medicating with cannabinoids may provide some pain relief to FM (fibromyalgia) patients, we caution against general use of illicit drugs until health and psychosocial issues risks are confirmed.”
Of the 457 fibromyalgia patients included in the study and being treated at the Alan Edwards Pain Management Unit of the MUHC, 13% reported using cannabinoids, the active ingredient in marijuana. One in three men in the study said they used cannabinoids, compared with 11% of the women. The amount typically used by marijuana smokers was about a gram per day.
Because traditional fibromyalgia treatments often have only modest results, some patients take it upon themselves to self-medicate using unconventional methods, including marijuana.
“Physicians should be alert to potential negative mental health issues in FM patients using illicit drugs for medical purposes,” Fitzcharles wrote.”Some herbal cannabis users may be dishonestly using a FM diagnosis to justify self-medicating with illegal drugs.”
Opioid painkillers were used by nearly half of the cannabinoid users in the study. Opioids are being increasingly prescribed for fibromyalgia patients, according to researchers, despite the fact that they are not recommended in current medical guidelines.
Seventy seven percent of the patients smoking marijuana were unemployed, suggesting “either the absence of a favorable effect on function or more serious functional impairment among those using cannabis,” the researchers noted. Marijuana smokers were also more likely to display “opioid-seeking behavior” (17%) and to show signs of mental illness (36%).
“Medical studies of cannabinoids in management of disease, including FM, have been limited,” wrote Fitzcharles, who urged that further studies be done. “Marijuana is the most common form of cannabinoid, but an illegal substance in most countries, making it difficult to investigate without possible prosecution for possessing an illicit substance.
The study findings are published in Arthritis Care & Research on behalf of the American College of Rheumatology.