Chapter 15 – Drug Addiction and the Brain’s Reward Circuits

Oral drug administration

Drug taken by mouth absorbed through the digestive tract and slow in onset.

Injection drug administration

Drug delivered directly into bloodstream muscle or skin for rapid effects.

Inhalation drug administration

Drug absorbed through lungs producing fast brain effects.

Drug sensitization

Increased response to a drug following repeated exposure.

Metabolic tolerance

Reduced drug effect because the body metabolizes it more efficiently.

Functional tolerance

Reduced drug effect due to changes in neural sensitivity or receptor function.

Addiction

Compulsive drug seeking and use despite negative consequences.

Tobacco withdrawal

Irritability anxiety and craving after nicotine cessation.

Alcohol withdrawal

Tremors anxiety and seizures after cessation of drinking.

Opiate withdrawal

Pain craving and flu-like symptoms following heroin or morphine use.

Methadone treatment

A long-lasting opiate agonist used to reduce craving without producing a high.

Buprenorphine treatment

A partial opiate agonist that prevents withdrawal with lower abuse potential.

Mesocorticolimbic dopamine pathway

Reward circuit involving VTA nucleus accumbens and prefrontal cortex.

Incentive-sensitization theory

Addiction theory where wanting increases but liking decreases over time.

Relapse triggers

Stress drug-related cues and single reexposure to the drug cause return to use.