Cannabis, also known as marijuana, and by numerous other names, is a preparation of the Cannabis plant intended for use as a psychoactive drug and as medicine. Pharmacologically, the principal psychoactive constituent of cannabis is tetrahydrocannabinol; it is one of 483 known compounds in the plant, including at least 84 other cannabinoids, such as cannabidiol, cannabinol, tetrahydrocannabivarin. and cannabigerol.
Cannabis is often consumed for its psychoactive and physiological effects, which can include heightened mood or euphoria, relaxation, and increase in appetite. Unwanted side-effects can sometimes include a decrease in short-term memory, dry mouth, impaired motor skills, reddening of the eyes, and feelings of paranoia or anxiety.
Contemporary uses of cannabis are as a recreational or medicinal drug, and as part of religious or spiritual rites; 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 has said that cannabis is the most-used illicit drug in the world. In 2004, the United Nations estimated that global consumption of cannabis indicated that approximately 4% of the adult world population used cannabis annually, and that approximately 0.6% of people used cannabis daily.
Cannabis has psychoactive and physiological effects when consumed. The immediate desired effects from consuming cannabis include relaxation and mild euphoria, while some immediate undesired side-effects include a decrease in short-term memory, dry mouth, impaired motor skills and reddening of the eyes. Aside from a subjective change in perception and, most notably, mood, the most common short-term physical and neurological effects include increased heart rate, increased appetite and consumption of food, lowered blood pressure,...