A group of psychoactive drugs that can produce hallucinations (auditory, visual, or kinesthetic), distorted sensory experiences, alterations of mood, and distorted thinking.

A disturbance of non-REM sleep, generally occurring in children; characterized by screaming, staring fearfully, and usually no memory of the episode the following morning.

A synthetic drug chemically similar to the stimulant methamphetamine and the hallucinogen mescaline; produces a combination of stimulant and hallucinogenic effects.

Sleep disorder characterized by an inability to fall asleep or stay asleep, impacting both the quality and the quantity of sleep.

A class of psychoactive drugs that depress or slow down activity in the central nervous system.

With constant use of some psychoactive drugs, the body no longer functions normally without the drug.

The hidden meaning of a dream, often concealed by the manifest content of the dream.

Brain waves that indicate light sleep.

Frightening dreams that occur during REM sleep.

A serious disturbance of non-REM sleep characterized by complete absence of air flow (apnea) or reduced air flow (hypopnea).

Brain waves that indicate an alert, awake state.

The apparent meaning of a dream; the remembered story line of a dream.

Brain waves that indicate a deep sleep.

Substances that can cause changes in psychological activities such as sensation, perception, attention, judgment, memory, self-control, emotion, thinking, and behavior; substances that cause changes in conscious experiences.

A neurological disorder characterized by excessive daytime sleepiness, which includes lapses into sleep and napping.

A class of psychoactive drugs that cause a sense of euphoria; a drug that imitates the endorphins naturally produced in the brain.

The state of being aware of oneself, one’s thoughts, and/or the environment; includes various levels of conscious awareness.

With constant use of some psychoactive drugs, a strong desire or need to continue using the substance occurs without the evidence of tolerance or withdrawal symptoms.

The active ingredient of marijuana.

Detection, encoding, and sometimes storage of information without conscious effort or awareness.

With constant use of some psychoactive drugs, a condition in which the body becomes dependent and then reacts when the drug is withheld; a sign of physiological dependence.

The stage of sleep associated with dreaming; sleep characterized by bursts of eye movements, with brain activity similar to that of a waking state, but with a lack of muscle tone.

Depressant drug that decreases neural activity and reduces anxiety; a type of sedative.

The ability to focus awareness on a small segment of information that is available through our sensory systems.

This theory proposes that humans respond to random neural activity while in REM sleep as if it has meaning.

Withdrawal symptoms that can occur when a heavy drinker suddenly stops or significantly cuts down alcohol consumption; can include sweating, restlessness, hallucinations, severe tremors, and seizures.

The daily patterns roughly following the 24-hour cycle of daylight and darkness; and 24-hour cycle of physiological and behavioral functioning.

A class of drugs that increase neural activity in the central nervous system.

With constant use of some psychoactive drugs, a condition in which the body requires more and more of the drug to create the original effect; a sign of physiological dependence.

A synthetically produced, odorless, tasteless, and colorless hallucinogen that is very potent; produces extreme changes in sensations and perceptions.

A class of psychoactive drugs that minimizes perceptions of pain.

A sleep disturbance in which the mechanism responsible for paralyzing the body during REM sleep is not functioning, resulting in the acting out of dreams.

An increased amount of time spent in REM during the first sleep session after sleep deprivation.

An altered state of consciousness allowing for changes in perceptions and behaviors, which result from suggestions made by a hypnotist.

The nondreaming sleep that occurs during sleep Stages 1 to 4.

Brain waves that indicate a relaxed, drowsy state.

Stimulant drugs; methamphetamine falls in this class of drugs.