 Intervention if applicable: Patients will, in this cross-over study, receive a maximum 6 chewing gums per day, either containing 50 mg of cannabidiol per chewing gum in case of the CanChew chewing gum, or a placebo chewing gum. This first intervention period will last 3 weeks. Next, participants will undergo a one week wash-out and then switch intervention to either placebo or the CanChew chewing gum for another 3 weeks. 