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Arthritis Care & Research

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Edited by: Marian T. Hannan, DSc, MPH
Print ISSN: 2151-464X Online ISSN: 2151-4658
Published on behalf of American College of Rheumatology
Impact Factor: 4.039

12:00 AM EDT June 21, 2012

Medicinal Marijuana Use Found in 10% of Fibromyalgia Patients

Doctors Caution Self-medicating with Herbal Cannabis Sparks Poor Mental Health

New research reveals that 10% of fibromyalgia (FM) patients use marijuana for medicinal relief from symptoms such as widespread pain, fatigue, and insomnia caused by this chronic illness. Findings published in Arthritis Care & Research, a journal published by Wiley-Blackwell on behalf of the American College of Rheumatology (ACR), suggest that patients who self-medicate with herbal cannabis have poorer mental health. While experts believe that cannabinoids may offer some therapeutic effect, they caution against any recommendations until psychosocial and health issues can be further clarified.

Patients with FM—a chronic pain syndrome causing widespread pain, unexplained fatigue, headaches, sleep disturbances, and other somatic symptoms—affects up to 3% of the population and is more common in women. Herbal cannabis is one pain treatment used for centuries, but in more modern times has mainly been used outside of conventional medicine. FM pharmacologic treatments for pain have modest results, say experts, prompting some patients to self-medicate with more non-traditional therapies, such as marijuana.

“Medical studies of cannabinoids in management of disease, including FM, have been limited,” comments lead author, Dr. Mary-Ann Fitzcharles, a professor of medicine at McGill University and consulting rheumatologist at the Montreal General Hospital of the McGill University Health Centre (MUHC) in Montreal, Canada. “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.

For the present study, Dr. Fitzcharles and colleagues documented self-reported cannabinoid use in 457 FM patients being treated at the Alan Edwards Pain Management Unit of the MUHC. The team validated the FM diagnosis and investigated associations and trends of self-medicating with medical marijuana or cannabis, prescription cannabinoids, or both. Patient pain levels were measured using the visual analog scale (VAS), their functional ability was assessed with the Fibromyalgia Impact Questionnaire (FIQ), and a psychologist evaluated all FM participants for prior or current psychiatric conditions according to the Diagnostics and Statistical Manual of Mental Disorder (DSM-IV).

An FM diagnosis was confirmed by Dr. Fitzcharles in 302 participants and 155 patients were assigned another primary diagnosis, the non-FM group. Researchers determined that 13% of all 457 participants used cannabinoids, with 80% using herbal cannabis/marijuana. Analysis found that 24% of cannabinoid users used prescription cannabinoids such as nabilone and dronabinol, and 3% were both herbal cannabis and prescription cannabinoid users. Those smoking marijuana consumed up to 6 grams, with 72% reporting use of 1 gram or less per day.

Further results reveal that one third of all males used cannabinoids. The team determined that herbal cannabis use was associated with unstable mental illness, opioid drug-seeking behavior, and male gender at 36%, 17% and 26%, respectively compared to 23 %, 4%, and 7% for non-users. A 77% unemployment rate was identified in herbal marijuana users, which researchers believe may be due to ineffective pain control to improve functionality or a more serious functional disability.

“While self-medicating with cannabinoids may provide some pain relief to FM patients, we caution against general use of illicit drugs until health and psychosocial issues risks are confirmed,” concludes Dr. Fitzcharles. “Physicians should be alert to potential negative mental health issues in FM patients using illicit drugs for medical purposes. Some herbal cannabis users may be dishonestly using a FM diagnosis to justify self-medicating with illegal drugs.