Recreational drug use is the use of a drug (legal, controlled, or illegal) with the primary intention to alter the state of consciousness (through alteration of the central nervous system) in order to create positive emotions and feelings. The popular concept of this phenomenon puts it closer to a social behaviour that many places around the world tolerate rather than to serious medical conditions such as self-medication. When a substance enters the user's body, it brings on an intoxicating effect; in terms of psychoactive drugs, such as cannabis or MDMA, this is often referred to as a "high".