In a study with 26 patients with fibromyalgia, who had been treated at two hospitals in Israel (Laniado Hospital in Kiryat Sanz and Nazareth Hospital in Nazareth) cannabis improved their symptoms. Their mean age was 37.8 years and mean dosage of cannabis was 26 g per month. All participants completed a questionnaire for the assessment of fibromyalgia severity (Revised Fibromyalgia Impact Questionnaire).
After commencing treatment with cannabis , all the patients reported a significant improvement in every parameter on the questionnaire, and 13 patients (50%) stopped taking any other medications for fibromyalgia. Eight patients (30%) experienced very mild adverse effects.