Objective

Use of medical cannabis for improving symptoms of inflammatory bowel disease is increasing. However, reports on long-term outcomes are lacking. This prospective, observational study assessed the effects of licensed cannabis use among patients with inflammatory bowel disease.

Methods

Dose and mode of consumption, adverse events, use of other medications, and long-term effects were evaluated among 127 patients with inflammatory bowel disease using legalized medical cannabis. Blood count, albumin, and C-reactive protein were assessed before, 1 month, and at least 1 year after medical cannabis therapy was initiated. Questionnaires on disease activity, patient function, and signs of addiction were completed by patients and by a significant family member to assess its effects.

Results

The average dose used was 31 ± 15 g/month. The average Harvey-Bradshaw index improved from 14 ± 6.7 to 7 ± 4.7 (P < 0.001) during a median follow-up of 44 months (interquartile range, 24–56 months). There was a slight, but statistically significant, average weight gain of 2 kg within 1 year of cannabis use. The need for other medications was significantly reduced. Employment among patients increased from 65 to 74% (P < 0.05). We conclude that the majority of inflammatory bowel disease patients using cannabis are satisfied with a dose of 30 g/month. We did not observe negative effects of cannabis use on the patients’ social or occupational status.

Conclusions

Cannabis use by inflammatory bowel disease patients can induce clinical improvement and is associated with reduced use of medication and slight weight gain. Most patients respond well to a dose of 30 g/month, or 21 mg Δ9-tetra- hydrocannabinol (THC) and 170 mg Cannabidiol (CBD) per day.