Module 1.3b: The Neuron, Neural Firing, Substance Use Disorder, and Psychoactive Drugs

Vocabulary practice flashcards covering psychoactive drug classifications, neurochemical mechanisms of action (agonists, antagonists, reuptake inhibitors), tolerance, dependence, and substance use disorders based on Module 1.3b.

Consciousness

The characteristics of awareness at any particular moment, which can range from deep sleep to alert wakefulness and includes both active (e.g., problem-solving) and passive (e.g., daydreaming) states.

Psychoactive Drugs

Chemical substances not usually needed for physiological activity that affect the brain, altering consciousness, perceptions, moods, and other psychological processes.

Psychopharmacology

The branch of science devoted to the study of psychoactive drugs and their effects on behavior, mental processes, and interactions between neurotransmitters and receptors.

Substance Use Disorder

A condition characterized by continued, compulsive substance use despite significant life disruption, cognitive or physical impairment, and hazardous consequences.

Blood-Brain Barrier

A semipermeable barrier of specialized blood vessels supplying the brain that only permits certain molecules and substances to pass through and interact with brain tissue.

Agonist

A drug molecule structurally similar enough to a neurotransmitter to bind to its receptor site and mimic the effects of that normal neurotransmitter (e.g., heroin mimicking endorphins).

Antagonist

A drug molecule that is similar enough to bind to a receptor site to occupy it without activating it, thereby blocking the normal neurotransmitter from binding (e.g., naloxone/Narcan).

Reuptake Inhibitor

A drug that blocks the reabsorption of neurotransmitters back into the presynaptic neuron, leaving molecules in the synaptic gap to continually activate receptor sites on the receiving neuron.

Reward Pathway

A neural circuit in the brain extending from the midbrain via the medial forebrain bundle to the nucleus accumbens and prefrontal cortex, which releases dopamine in response to rewarding stimuli or addictive drugs.

Drug Addiction

A chronic, relapsing brain disease characterized by compulsive drug seeking and use despite harmful consequences, resulting from changes to brain structure and functioning.

Psychological Dependence

A condition in which a person uses a drug despite adverse consequences because they rely on it for a sense of psychological well-being, emotional stability, or coping with daily stress.

Physical Dependence

A state of neuroadaptation characterized by a physical need for a drug, marked by the appearance of unpleasant and distressing withdrawal symptoms when the substance is stopped.

Tolerance

A condition resulting from continued drug exposure where brain chemistry adapts (neuroadaptation), requiring increasingly larger doses of the substance to produce the original desired effect.

Withdrawal

The physiological and psychological discomfort, distress, and adverse symptoms that follow the cessation or reduction of an addictive drug.

Expectancy Effects

Behavioral or physiological changes that occur because a person anticipates or believes they have consumed a psychoactive substance, regardless of whether an active drug was actually ingested.

Depressants

A class of psychoactive drugs (including alcohol, barbiturates, and benzodiazepines) that calm neural activity and slow down the body's physiological functions and nervous system.

Barbiturates

Sedative-hypnotic drugs (tranquilizers) such as Nembutal, Seconal, and Amytal that depress central nervous system activity, impair memory and judgment, and carry lethal potential when combined with alcohol.

Benzodiazepines

A class of depressant tranquilizers (such as Valium, Xanax, Buspar, and Rohypnol) that slow central nervous system activity, commonly used to alleviate anxiety or induce sleep.

Binge Drinking

The consumption of five or more alcoholic drinks within a short period of time.

Delirium Tremens

A severe, potentially life-threatening alcohol withdrawal syndrome characterized by tremors (the shakes), hallucinations, delusions, confusion, fever, hypertension, and tachycardia.

Opioids

Depressant and analgesic substances (such as heroin, morphine, codeine, oxycodone, and fentanyl) that alleviate pain and generate euphoria by binding to endogenous endorphin receptors.

Substance P

A neurotransmitter that transmits pain messages across the synaptic gap; its release and binding are suppressed by opioids like heroin.

Stimulants

A class of psychoactive drugs (such as caffeine, nicotine, cocaine, and amphetamines) that excite neural activity, increase alertness and mobility, speed up body functions, and decrease reaction time.

Nicotine

A highly addictive stimulant found in tobacco and vape products that triggers the release of epinephrine, norepinephrine (increasing alertness), and dopamine (calming anxiety).

Cocaine

A powerful stimulant that blocks the reuptake of dopamine, serotonin, and norepinephrine, producing intense euphoria, confidence, and alertness followed by an agitated crash.

Methamphetamine

A powerfully addictive stimulant that triggers large releases of dopamine to enhance mood and energy; chronic use damages baseline dopamine pathways, leading to depressed functioning.

Ecstasy (MDMA)

A synthetic stimulant and mild hallucinogen that triggers a massive release and blocks reuptake of serotonin, dopamine, and norepinephrine, producing heightened energy and emotional connectedness.

Hallucinogens

Psychedelic ('mind-manifesting') drugs (such as LSD, psilocybin, mescaline, and PCP) that distort sensory perceptions and evoke vivid sensory images in the absence of actual external sensory input.

Near-Death Experience (NDE)

An altered state of consciousness reported following a close brush with death (e.g., cardiac arrest), which often features hallucinations that closely parallel psychedelic drug experiences.

THC (Delta-9-tetrahydrocannabinol)

The major psychoactive ingredient in cannabis that overactivates cannabinoid receptors in the brain, altering sensory perception, mood, coordination, and sense of time.