Cannabis, also known as marijuana and by numerous other names, is a preparation of the Cannabis plant intended for use as a psychoactive drug or medicine. The main psychoactive part of cannabis is tetrahydrocannabinol (THC); it is one of 483 known compounds in the plant, including at least 84 other cannabinoids, such as cannabidiol (CBD), cannabinol (CBN), and tetrahydrocannabivarin (THCV).
Cannabis is often consumed for its mental and physical effects, such as a "high" or "stoned" feeling, a general alteration of conscious perception, heightened mood, relaxation, and an increase in appetite. Possible side effects include a decrease in short-term memory, dry mouth, impaired motor skills, red eyes, and feelings of paranoia or anxiety. Onset of effects is within minutes when smoked and about 30 minutes when eaten as a cooked cannabis edible. They last for between two and six hours.
Cannabis is mostly used recreationally or as a medicinal drug. It may also be used as part of religious or spiritual rites. In 2013, between 128 and 232 million people used cannabis (2.7% to 4.9% of the global population between the ages of 15 and 65). In 2015, almost half of the people in the United States have tried marijuana, 12% have used it in the past year, and 7.3% have used it in the past month.
The earliest recorded uses date from the 3rd millennium BC. Since the early 20th century, cannabis has been subject to legal restrictions, with the possession, use, and sale of cannabis preparations containing psychoactive cannabinoids currently illegal in most countries of the world; the United Nations deems it the most-used illicit drug in the world. Medical cannabis refers to the physician-recommended use of cannabis, which is taking place in Canada, Belgium, Australia, the Netherlands, Spain, and 23 U.S. states. Cannabis use started to become popular in the US in the 1970s. Support for legalization has been increasing in the United States in recent years and several US states have legalized recreational or medical use.