A psychoactive drug, psychopharmaceutical, or psychotropic is a chemical substance that crosses the blood–brain barrier and acts primarily upon the central nervous system where it affects brain function, resulting in changes in perception, mood, consciousness, cognition, and behavior. These substances may be used recreationally, to purposefully alter one’s consciousness, as entheogens, for ritual, spiritual, and/or shamanic purposes, as a tool for studying or augmenting the mind, or therapeutically as medication.
Psychoactive drugs are divided into three groups according to their pharmacological effects:
- Stimulants (“uppers”). This category comprises substances that wake one up, stimulate the mind, and may even cause euphoria, but do not affect perception.
Examples: coffee, tobacco, amphetamine, tea, cacao, guarana, maté, ephedra, khat, and coca.
- Depressants (“downers”), including sedatives, hypnotics, and narcotics. This category includes all of the calmative, sleep-inducing, anxiety-reducing, anesthetizing substances, which sometimes induce perceptual changes, such as dream images, and also often evoke feelings of euphoria.
Examples: opioids, barbiturates, benzodiazepines, and alcohol.
- Hallucinogens, including psychedelics, dissociatives and deliriants. This category encompasses all those substances that produce distinct alterations in perception, sensation of space and time, and emotional states.
Examples: psilocybin, LSD, Salvia divinorum, marijuana and nitrous oxide.
A psychiatric medication is a licensed psychoactive drug taken to exert an effect on the mental state and used to treat mental disorders. Usually prescribed in psychiatric settings, these medications are typically made of synthetic chemical compounds, although some are naturally occurring, or at least naturally derived.
Psychiatric medications are prescribed for the management of mental and emotional disorders. There are six major classes of psychiatric medications:
- Antidepressants, which are used to treat disparate disorders such as clinical depression, dysthymia,anxiety, eating disorders and borderline personality disorder.
- Stimulants, which are used to treat disorders such as attention deficit disorder and narcolepsy and to suppress the appetite.
- Antipsychotics, which are used to treat psychosis, schizophrenia and mania.
- Mood stabilizers, which are used to treat bipolar disorder and schizoaffective disorder.
- Anxiolytics, which are used to treat anxiety disorders.
- Depressants, which are used as hypnotics, sedatives, and anesthetics.