Cannabidiol and Cannabis Concentrate Users

This study is a randomized, placebo-controlled, dose-ranging trial of plant-derived cannabidiol (CBD) among people who regularly use cannabis concentrates but are not trying to stop or cut down on their use. The main questions it aims to answer are whether CBD, relative to placebo, reduces cannabis concentrate use, the subjective effects of cannabis, or cannabis craving. Participants will take CBD (200 mg or 400 mg per day) or placebo for 4 weeks and will complete three visits during the study medication period, all conducted using a mobile laboratory.