Substance Use Disorders and Psychoactive Drugs: Definitions and Effects

Substance use disorder

a disorder characterized by continued substance use despite resulting life disruption

Psychoactive drug

a chemical substance that alters the brain, causing changes in perceptions and moods

Depressants

drugs that reduce neural activity and slow body functions

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

Addiction

an everyday term for compulsive substance use that continues despite harmful consequences

Withdrawal

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

Barbiturates

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

Opiates

Opium and its derivatives (morphine and heroin); opiates depress neural activity, temporarily lessening pain and anxiety

Stimulants

drugs that excite neural activity and speed up body functions

Hallucinogens

psychedelic (mind-manifesting) drugs (like 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, often similar to drug-induced hallucinations