Cannabis Use Disorder (CUD), is the continued use of cannabis despite clinically significant impairment. Cannabis is a psychoactive drug used primarily for medical or recreational purposes. The main psychoactive component of cannabis is tetrahydrocannabinol (THC).
Cannabis is the most commonly used illegal drug both in the United States and the world, although it is also legal in some jurisdictions. In the United States, approximately 50% of people have used cannabis and approximately 10% of users develop cannabis dependence. Recreational use of cannabis has been legalized in some countries. Medical use of cannabis, requiring the approval of a physician, has been legalized in a greater number of countries.