Consciousness
our awareness of ourselves and our environment
Circadian Rhythm
the 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
Alpha Waves
the relatively slow brain waves of a relaxed, awake state
Sleep
periodic, natural loss of consciousness--as distinct from unconsciousness resulting from a coma, general anesthesia, or hibernation
Hallucinations
false sensory experiences, such as seeing something in the absence of an external visual stimulus
Delta Waves
the large, slow brain waves associated with deep sleep
NREM Sleep
non-rapid eye movement sleep; encompasses all sleep stages except for REM sleep
Insomnia
recurring problems in falling or staying asleep
Narcolepsy
a sleep disorder characterized by uncontrollable sleep attacks. The sufferer my lapse directly into REM sleep, often at inopportune times
Sleep Apnea
a sleep disorder characterized by temporary cessations of breathing during sleep and repeated momentary awakenings
Night Terrors
a sleep disorder characterized by high arousal and an appearance of being terrified; unlike nightmares, night terrors occur during Stage 4 sleep, within two or three hours of falling asleep, and are seldom remembered
Dream
a sequence of images, emotions, and thoughts passing through a sleeping person's mind. Dreams are notable for their hallucinatory imagery, discontinuities, and incongruities, and for the dreamer's delusional acceptance of the content and later difficulties remembering it
Manifest Content
according to Freud, the remembered story line of a dream
Latent Content
according to Freud, the underlying meaning of a dream
REM Rebound
the tendency for REM sleep to increase following REM sleep deprivation (created by repeated awakenings during REM sleep)
Hypnosis
a social interaction in which one person (the hypnotist) suggests to another (the subject) that certain perceptions, feelings, thoughts, or behaviors will spontaneously occur
Posthypnotic Suggestion
a suggestion, made during a hypnosis session, to be carried out after the subject is no longer hypnotized; used by some clinicians to help control undesired symptoms and behaviors
Dissociation
a split in consciousness, which allows some thought and behaviors to occur simultaneously with others
Psychoactive Drug
a chemical substance that alters perceptions and moods
Tolerance
the diminishing effect with regular use of the same does 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 the use of an addictive drug
Physical Dependence
a physiological need for a drug, marked by unpleasant withdrawal symptoms when the drug is discontinued
Psychological Dependence
a psychological need to use a drug, such as to relieve negative emotions
Addiction
compulsive drug craving and use, despite adverse consequences
Barbiturates
drugs that depress the activity of the central nervous system, reducing anxiety but impairing memory and judgement
Opiates
opium and its derivatives such as morphine and heroin; they depress neural activity, temporarily lessening pain and anxiety
Stimulants
drugs that excite neural activity and sped up body functions
Amphetamines
drugs that stimulate neural activity, causing speeded-up body functions and associated energy and mood changes
Methamphetamine
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
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 cognition
LSD
a powerful halucinogenic drug; also known as acid
Hallucinogens
psychedelic ("mind-manifesting") drugs, such as LSD, that distort perceptions and evoke sensory images in the absence of sensory input
Depressants
drugs that reduce neural activity and slow body functions
Near-Death Experience
an altered state of consciousness reported after a close brush with death; often similar to drug-induced hallucinations
THC
the major active ingredient in marijuana; triggers a variety of effects, including mild hallucinations