psychoactive drug

a chemical substance that alters perceptions and moods

substance use disorder

a disorder characterized by continued substance craving and use despite significant life disruption and/or physical risk

tolerance

the diminishing effect with regular use of the same dose of a drug, requiring the user to take larger and larger doses before experiencing the drug's effect

withdrawal

the discomfort and distress that follow discontinuing an addictive drug or behavior

depressants

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

alcohol use disorder

(popularly known as alcoholism) alcohol use marked by tolerance, withdrawal, and a drive to continue problematic use

barbiturates

drugs that depress central nervous system activity, reducing anxiety but impairing memory and judgement

opiates

opium and its derivatives, such as morphine and heroin; depress neural activity, temporarily lessening pain and anxiety

stimulants

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

nicotine

a stimulating and highly addictive psychoactive drug in tobacco

cocaine

a powerful and addictive stimulant derived from the coca plant; produces temporarily increased alertness and euphoria

amphetamines

drugs that stimulate neural activity, causing accelerated body functions and associated energy and mood changes

methamphetamine

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

Ecstasy (MDMA)

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

hallucinogens

psychedelic ("mind-manifesting") drugs, such as LSD, that distort perceptions and evoke sensory images in the absence of sensory input

near-death experience

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

LSD

a powerful hallucinogenic drug; also known as acid (lysergic acid dietyhlamide)

THC

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