Psychoactive drug

A psychoactive drug, psychopharmaceutical, or psychotropic is a chemical substance that changes brain function and results in alterations in perception, mood, or consciousness. These substances may be used recreationally (either legally or illegally, depending on the drug and the jurisdiction of the user) to purposefully alter one's consciousness, or as entheogens, for ritual, spiritual, or shamanic purposes, as a tool for studying or augmenting the mind. Some categories of psychoactive drugs, which have medical therapeutic value, are prescribed by medical doctors and other health care professionals. Examples include anesthetics, analgesics, hormonal preparations, anticonvulsant and antiparkinsonian drugs or drugs used for the treatment of neuro-psychiatric disorders, as hypnotic drugs, anxiolytic and some stimulant medications used in ADHD and some sleep disorders. There are also some psychoactive substances used in the detoxification and rehabilitation programs for psychoactive drug users.

Psychoactive substances often bring about subjective (although these may be objectively observed) changes in consciousness and mood that the user may find rewarding and pleasant (e.g. euphoria or a sense of relaxation) or advantageous (e.g. increased alertness) and are thus reinforcing. Substances which are both rewarding and positively reinforcing have the potential to induce a state of addiction – compulsive drug use despite negative consequences – when used consistently in excess. In addition, sustained use of some substances may produce a physical dependence or psychological dependence syndrome associated with somatic or psychological-emotional withdrawal states respectively. Drug rehabilitation aims to break this cycle of dependency, through a combination of psychotherapy, support groups, maintenance and even other psychoactive substances. However, the reverse is also true in some cases, that certain experiences on drugs may be so unfriendly and uncomforting that the user may never want to try the substance again. This is especially true of certain deliriants (e.g. Jimson weed), powerful dissociatives (e.g. Salvia divinorum), and classic psychedelics (e.g. LSD, psilocybin), in the form of a "bad trip".

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