Ch. 5: Drugs, Addiction, and Reward

Addiction: A preoccupation with obtaining a drug, compulsive use of the drug in spite of adverse consequences, and a high tendency to relapse after quitting. Distinct from dependence.

Agonist Treatment: Addiction treatment that replaces the addicting drug with another drug that has a similar effect.

Alcohol: Ethanol, a drug fermented from fruits, grains, and other plant products, which acts at many brain sites to produce euphoria, anxiety reduction, motor incoordination, and cognitive impairment.

Amphetamine: One of a group of synthetic drugs that produce euphoria and increase confidence and concentration.

Analgesic: Pain relieving.

Antagonist Treatment: A form of treatment for drug addiction using drugs that block the effects of the addicting drug.

Antidrug Vaccine: A form of anti-addiction treatment using molecules that attach to the drug and stimulate the immune system to make antibodies that will break down the drug.

Anxiolytic: Anxiety reducing.

Aversive Treatment: A form of addiction treatment that causes a negative reaction when the person takes the drug.

Barbiturate: A class of drugs that act selectively on higher cortical centers, especially those involved in inhibiting behavior, so they produce talkativeness and increased social interaction. In higher doses, they act as sedatives and hypnotics. They are used to treat anxiety, aid sleep, and prevent epileptic convulsions.

Bath Salts: Any one of several synthetic derivatives of the Catha edulis plant that have amphetamine-like effects.

Benzodiazepine: A class of drugs that produce anxiety reduction, sedation, and muscle relaxation by stimulating benzodiazepine receptors on the GABAA complex, facilitating GABA binding.

Caffeine: A drug that produces arousal, increased alertness, and decreased sleepiness; the active ingredient in coffee and tea.

Cannabinoids: A group of compounds that includes the active ingredient in marijuana (tetrahydrocannabinol, or THC) and the endogenous cannabinoid receptor ligands, anandamide, and 2-arachidonyl glycerol (2-Ara-Gl). Cannabinoids act as retrograde messengers.

Cocaine: A drug extracted from the South American coca plant that produces euphoria, decreased appetite, increased alertness, and relief from fatigue.

Delirium Tremens: A reaction in some cases of withdrawal from alcohol, including hallucinations, delusions, confusion, and, in extreme cases, seizures and possible death.

Dependence: The need to continue taking a drug to avoid the physical and psychological symptoms of withdrawal. Distinct from addiction.

Depressant: A drug that reduces central nervous system activity.

Drug: Any medicine or other substance that, on entering the body, changes the body’s functioning.

Endogenous: Generated within the body; usually used to refer to natural ligands for neurotransmitter receptors.

Endorphins: Substances produced in the body that function both as neurotransmitters and as hormones and that act on opioid receptors in many parts of the nervous system.

Euphoric: A term referring to a drug’s ability to produce a sense of happiness or ecstasy.

Heroin: A major drug of addiction synthesized from morphine.

Hypnotic: Sleep inducing.

Hypofrontality: Reduced activity in several frontal regions that control working memory, attention, behavioral inhibition, and the individual’s response to the environment.

Marijuana: The dried and crushed leaves and flowers of the plant Cannabis sativa.

Mesocorticolimbic Dopamine System: The ventral tegmental area and the brain regions receiving its dopaminergic projections, including the nucleus accumbens, prefrontal cortex, amygdala, and hippocampus. The system is important in reward and addiction.

Mesolimbic Pathway: A dopaminergic pathway originating in the ventral tegmental area and projecting to several locations in the limbic system, particularly the nucleus accumbens. The pathway is important in responding to rewarding stimuli.

Methadone: A synthetic opioid used as an agonist treatment for opiate addiction.

Methylation: Attachment of a methyl group to DNA, which suppresses a gene’s activity. See also epigenetic.

Nicotine: The primary psychoactive and addictive ingredient in tobacco.

Nucleus Accumbens: A forebrain structure that is part of the mesolimbocortical dopamine system and a potent center for reward.

Opiate: Any drug derived from the opium poppy. The term is also used to refer to effects at opiate receptors, including those by endorphins.

Psychedelic Drug: Any compound that causes perceptual distortions in the user.

Psychoactive Drug: Any drug that has psychological effects, such as anxiety relief or hallucinations.

Reward: The positive effect on a user from a drug, electrical stimulation of the brain (ESB), sex, food, warmth, and so on.

Sedative: A calming effect of a drug.

Stimulant: A drug that activates the nervous system to produce arousal, increased alertness, and elevated mood.

Tolerance: After repeated drug use, the individual becomes less responsive and requires increasing amounts of a drug to produce the same results.

Ventral Tegmental Area: A part of the mesolimbocortical dopamine system, which sends neurons to the nucleus accumbens and is a potent reward area.