Background: Irritable bowel syndrome (IBS) is one of the most common gastrointestinal disorders. Its pathophysiology is diverse and variable, involving disturbed gut-brain interactions, altered motility and secretion, visceral hypersensitivity, increased intestinal permeability, immune activation, and changes in gut microbiota. Complaints experienced by patients suffering from IBS and its co-morbidities strongly impair quality of life (QoL), and available treatments are often unsatisfactory. Anecdotal reports and preclinical data suggest that the endocannabinoid system and functionally related mechanisms could offer treatment targets. Cannabidiol (CBD) is a candidate agent of interest with a broad molecular target profile and the absence of psychoactive properties. Materials and Methods: In 32 female IBS patients, we explored the effect of a chewing gum formulation containing 50 mg CBD on abdominal pain and perceived well-being in a randomized, double-blinded, placebo-controlled cross-over trial. Chewing gums were used on-demand guided by pain symptoms with a maximum of six per day. Pain intensity was assessed by a visual analogue scale (scale 0.0-10.0), and QoL was evaluated with the IBS-36 questionnaire. Results: There was no statistically significant difference in pain scores between CBD and placebo at a group level. Subgroup and individual analyses showed a highly variable picture. No indications were found for symptom-driven intake, which also remained lower than expected overall. Conclusions: With the current design, based on the assumption that IBS patients would adjust their intake to their perceived symptom relief, no differences at the group level were found between CBD and placebo gum in pain scores and the number of gums used. The low use of the gums also indicates that the benefits experienced by these patients generally did not outweigh practical disadvantages such as prolonged chewing throughout the day. The very high intra- and inter-individual variation in IBS symptoms warrant future trials that are more personalized, for example by applying an N-of-1 (rotating) design with individualized dose titration.
Keywords: cannabidiol; chewing gum; irritable bowel syndrome.