The main finding of the present study was that MC treatment was associated with significant favorable outcomes in every item evaluated in the FIQR. In some cases, the improvement was so marked that the patients completely ceased treatments they had taken previously. In other cases, the patients significantly reduced the dose or type of medication they had taken prior to MC treatment.
The patients expressed the effects of the treatment in their own words, and their responses were dramatic. Very rarely as physicians have we encountered such responses in real-life medicine, except possibly among patients treated with steroids for inflammatory conditions, such as polymyalgia rheumatica or rheumatoid arthritis.
Examples of the patients' responses were as follows: "I wish I had received this treatment when I was first diagnosed with fibromyalgia," "I returned to be the same person as before," "I regained my health," and "This is a miraculous treatment."
For some items of the FIQR, all the patients reported a favorable outcome. These included the effect of MC on pain and energy levels. For other items, the impact was less prominent, yet significant. These included the impact of MC on memory problems and daily activities of living, such as household activities (e.g., cleaning the house and changing bed sheets) and shopping (e.g., carrying grocery bags).
Another major benefit of MC treatment was a lack of serious adverse effects. The patients reported a few mild adverse effects, including dry mouth, redness of the eyes, and feeling hungry. These adverse effects appeared from the start of the treatment. The first 2 adverse effects were usually transient, lasting only a few weeks, and were mainly encountered in cases where the mode of MC was smoking. Many patients adapted to feeling hungry by eating prior to the use of MC.
The mean dose of MC consumed in the present study was relatively low (26 ± 8.2 g per month) as compared with that consumed by patients who receive MC for other indications, such as cancer pain. In the latter case, the dosage exceeded 60 g per month (personal communication, Dr. Salem Billan, oncologist, Rambam Medical Center, Haifa, oral communication, on July 1, 2017). In the present study, many patients continued to take 30 or even 20 g per month, which were the lowest starting doses, suggesting that consumption of approximately 1 g or less a day could be sufficient to control most symptoms of fibromyalgia. The findings of the present study should reassure health policy makers and health care providers that most fibromyalgia patients will remain on a relatively low dose.
There are no studies on tolerance among MC users. However, a previous study of other recreational cannabis users found no tolerance to subjective effects of cannabis.
In the current study, 12 patients (46%) reported either an improvement in their capacity to work or return to full-time work (data not shown). The aforementioned finding has implications for the patient, the patient's family, and society. A literature search revealed no studies on this issue of return to work, among patients treated with MC for different indications. However, a large study of the impact of illicit use of cannabis reported detrimental effects on employment and labor force.
Although previous research proposed a role for endocannabinoid deficiency in fibromyalgia, the potential role of endogenous cannabinoids in the pathogenesis of fibromyalgia remains unclear. More studies are needed to clarify their role. The distribution of cannabinoid receptors in the body may favor the proposed theory of central sensitization in the pathogenesis of fibromyalgia.
The long-term effects of MC treatment remain unclear. All MC request forms submitted to the Israeli Medical Cannabis Agency of the Ministry of Health that are signed by all patients clearly state that the long-term effects of MC are not known. Previous studies showed gray matter volume reductions in different parts of the cortex and functional impairments in various cognitive skills among cannabis users.[24,25] However, these studies involved individuals with heavy cannabis use and not patients under licensed MC treatment who received much lower doses.
Given the somewhat arbitrary selection of patients by the Israeli Medical Cannabis Agency to receive MC for their fibromyalgia, we do not know if the conclusions of our study could be generalized to all fibromyalgia patients, mainly those with severe pain. However, the consistent findings of the impact of MC on many of the FIQR items, especially on pain, allude to the validity of the results.
The main drawback of the present study was its retrospective nature, where patients were asked to answer questions regarding the period prior to their use of MC. However, most patients (~54%) answered the questionnaire a relatively short period after starting MC treatment (i.e., ≤3 months) Second, as mentioned earlier, fibromyalgia is not among the indications for MC treatment. Based on personal experience, fewer than 5% of requests for MC treatment for fibromyalgia are approved. Thus, it seemed unpractical to administer the questionnaire a priori to all patients with fibromyalgia whose doctor submitted a form for MC licensing.
J Clin Rheumatol. 2018;24(5):255-258. © 2018 Lippincott Williams & Wilkins