| A | B |
|---|
| Opiate | opium and its derivatives, such as morphine and heroin; depress neural activity, temporarily lessening pain and anxiety |
| Hallucination | a false sensory experience, such as hearing something in the absence of an external auditory stimulus |
| Consciousness | our awareness of ourselves and our environment |
| Circadian Rhythm | internal biological clock; regular bodily rhythms (for example, of temperature and wakefulness) that occur on a 24- hour cycle. |
| REM Sleep | rapid eye movement sleep; a recurring sleep stage during which vivid dreams commonly occur. Also known as paradoxical sleep, because the muscles are relaxed (except for minor twitches) but other body systems are active. |
| Sleep | periodic, natural loss of consciousness—as distinct from unconsciousness resulting from a coma, general anesthesia, or hibernation |
| Insomnia | recurring problems in falling or staying asleep |
| Narcolepsy | a sleep disorder in which a person has uncontrollable sleep attacks, sometimes lapsing directly into REM sleep |
| Sleep Apnea | a sleep disorder in which a sleeping person repeatedly stops breathing until blood oxygen is so low the person awakens just long enough to draw a breath. |
| Dream | a sequence of images, emotions, and thoughts passing through a sleeping person’s mind. |
| REM Rebound | the tendency for REM sleep to increase following REM sleep deprivation. |
| Psychoactive Drug | drug a chemical substance that alters perceptions and mood |
| Tolerance | a dwindling 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 ending the use of an addictive drug or behavior |
| Depressant | drugs (such as alcohol, barbiturates, and opiates) that reduce (depress) neural activity and slow body functions |
| Stimulants | drugs (such as caffeine, nicotine, and the more powerful cocaine, amphetamines, methamphetamine, and Ecstasy) that excite neural activity and speed up body functions. |
| Hallucinogen | psychedelic (“mind-manifesting”) drugs, such as LSD, that distort perceptions and trigger sensory images in the absence of sensory input. |
| Barbiturates | drugs that depress central nervous system activity, reducing anxiety but impairing memory and judgment |
| Cocaine | a powerful and addictive stimulant derived from the coca plant; temporarily increases alertness and produces feelings of euphoria |
| Alcohol Use Disorder | alcohol use marked by tolerance, withdrawal, and a drive to continue problematic use |
