Smoke Signals: What Does Marijuana Self-Medication Potentially Tell Us?

Fibromyalgia, or for that matter many chronic pain syndromes, are not uncommon in primary care. In the case of fibromyalgia, there is no ideal treatment. Patients with the diagnosis therefore may choose to seek pain relief from non-medical sources. One drug sought after is marijuana. A recent study looked at red flags generated by marijuana use in this particular cohort.¹

DISTURBING ASSOCIATIONS WITH CANNABIS USE

Four hundred and fifty-seven patients with fibromyalgia were asked to report self-medication with marijuana, and 13% said they were using it. This figure is consistent with a previous study that verified use by urine drug screens.

American College of Rheumatology criteria were applied to document the diagnosis of fibromyalgia. A psychologist evaluated all patients. Opioid-seeking behavior was identified according to validated criteria. A number of disturbing associations were demonstrated with cannabis use that might inform primary care practitioners about potentially serious problems.

•The cannabis group had a significantly higher incidence of unstable mental illness. There are data to suggest that cannabis use may exacerbate or precipitate psychiatric disease.

•Opioid drug-seeking behavior was more common in the group using cannabis.

•The unemployment rate of 77% in the cannabis cohort suggests either the absence of any favorable effects of cannabis on the disease or more serious functional impairments in the users.

•The risks associated with the combination of cannabis and other pharmacological treatments are unknown and may be serious.

•The diagnosis of fibromyalgia was incorrect in one-third of the patients in this study group.

•Since one-third of the entrants did not have fibro-myalgia at all, some persons may be using the diagnosis dishonestly to justify marijuana use or to request
narcotics.

IMPLICATIONS FOR PRIMARY CARE PRACTICE

Although the authors themselves identify limitations to their study (it was of small size and was conducted in a tertiary referral center, and the cannabis use was self-reported), the results will change my practice. I will be stricter with my diagnoses of fibromyalgia. I will consider marijuana use as a potential risk factor for other psychi-atric problems. I will also be more wary regarding requests for narcotics in this particular group and will consider urine testing for marijuana metabolites.