Consciousness
Our awareness of ourselves and our environment.
Biological rhythms
Periodic physiological fluctuations.
Circadian rhythm
The biological clock; regular bodily rhythms that occur on a 24 hour cycle.
REM sleep
A recurring sleep stage during which vivid dreams commonly occur. Also known as paradoxical sleep because the muscles are relaxed but other body systems are active
Alpha waves
The relatively slow brain waves of a relaxed, awake state.
Sleep
Periodic, natural, reversible loss of consciousness.
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.
Insomnia
Recurring problems in falling or staying asleep.
Narcolepsy
A sleep disorder characterized by uncontrollable sleep attacks. The sufferer may 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.
Dream
A sequence of images, emotions, and thought passing through a sleeping persons mind.
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.
Hypnosis
A social interaction in which one person suggest to another 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.
Dissociation
A split in consciousness, which allows some thoughts and behaviors to occur simultaneously with others.
Psychoactive drug
A chemical substance that alters perceptions and mood.
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 drugs effect.
Withdrawal
The discomfort and distress that follow discontinuing the use of an active 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.
Depressants
Drugs that reduce neural activity and slow body functions.
Barbiturates
Drugs that depress the activity of the CNS, reducing anxiety but impairing memory and judgement.
Opiates
Opium and it's derivatives, such as morphine and heroine; they depress neural activity, temporarily lessening pain and anxiety.
Stimulants
Drugs 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.
Methamphetamine
A powerfully addictive drug that stimulates the CNS, with speeded-up body functions and associated energy and mood changes; over time, appears to reduce the 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 drugs, such as LSD, that distort perceptions and evoke sensory images in the absence of sensory input.
LSD
A powerful hallucinogenic drug; also known as acid.
THC
The major active ingredient in marijuana; triggers a variety of effects, including mild hallucinations.
Near-death experience
An altered state of consciousness reported after a close brush with death; often similar to drug-induced hallucinations.
Dualism
The presumption that mind and body are two distinct entities that interact.
Monism
The presumption that mind and body are different aspects of the same thing.