Thirty volunteers were randomized to receive 750 mg of a plant-derived pharmaceutical formulation of highly purified CBD in oral solution (100 mg/mL; Epidiolex® in the United States and Epidyolex® in Europe) twice daily (b.i.d.) for 4 weeks (Part 1) followed by 2 weeks of 750 mg b.i.d. CBD (Part 2, Arm 1) or matched placebo (Part 2, Arm 2). All volunteers completed the Cannabis Withdrawal Scale (CWS) and the 20-item Penn Physician Withdrawal Checklist (PWC-20) on days − 1, 21, 28, 31, 35, 42, and at follow-up.

Results

Median CWS and PWC-20 scores slightly decreased from Part 1 to Part 2. Median CWS scores ranged from 0.0 to 4.0 (out of a possible 190) in Arm 1 and 0.0 to 0.5 in Arm 2. Median PWC-20 scores were 0.0 (out of a possible 60) in both arms. Twenty-nine (97%) volunteers in Part 1 reported all-causality treatment-emergent adverse events (AEs); the most commonly reported was diarrhea (63%). In Part 2, Arm 1, 6 (67%) volunteers reported all-causality AEs; the most commonly reported was diarrhea (44%). In Part 2, Arm 2, 9 (75%) volunteers reported all-causality AEs; the most commonly reported was headache (58%). Nine volunteers withdrew because of AEs in Part 1; 1 withdrew in Part 2, Arm 2, because of an AE that began in Part 1. Four severe AEs were reported in Part 1; the remainder were mild or moderate. No serious AEs were reported.