States of consciousness

depressants

Drugs (such as alcohol, barbiturates, and opiates) that reduce neural activity and slow body functions.

thc

The major active ingredient in marijuana; triggers a variety of effects, including mild hallucinations.

withdrawal

A pattern of uncomfortable or painful physical symptoms and cravings experienced by the user when the level of drug is decreased or the drug is eliminated.

addiction

A physical dependence on a substance.

physical dependence

A physiological need for a drug, marked by unpleasant withdrawal symptoms when the drug is discontinued

lsd

A powerful hallucinogenic drug; also known as acid (lysergic acid diethylamide).

tolerance

A progressive decrease in a person's responsiveness to a drug.

psychological dependence

A psychological need to use a drug, such as to relieve negative emotions

barbiturates

A category of depressant drugs that reduce anxiety and produce sleepiness.

opiates

A category of psychoactive drugs that are chemically similar to morphine and have strong pain-relieving properties.

hallucinogens

A diverse group of drugs that have powerful effects on mental and emotional functioning, marked most prominently by distortions in sensory and perceptual experience.

psychoactive drug

A drug that alters behavior, thought, or perception by altering biochemical reactions in the nervous system, thereby affecting consciousness

ecstasy

A synthetic stimulant and mild hallucinogen. Produces euphoria and social intimacy, but with short-term health risks and longer-term harm to serotonin-producing neurons and to mood and cognition.

stimulants

Drugs (such as caffeine, nicotine, and the more powerful amphetamines, cocaine, and Ecstasy) that excite neural activity and speed up body functions.

amphetamines

Drugs that stimulate neural activity, causing speeded-up body functions and associated energy and mood changes

methamphetamines

a powerfully addictive drug that stimulates the central nervous system, with speeded-up body functions and associated energy and mood changes; over time, appears to reduce baseline dopamine levels

near-death experience

an altered state of consciousness reported after a close brush with death (such as through cardiac arrest); often similar to drug-induced hallucinations