the relative likelihood that a particular psychoactive substance will reinforce drug-taking behavior to the point of abuse. Factors that determine abuse potential include subjective experience with a given substance, route of drug administration (e.g., intravenous, inhalation, oral), and the onset speed, duration, and nature of the drug effect. Substances with a high abuse potential include intravenous heroin, crack cocaine, morphine, and smoked opium. Substances with a low abuse potential include the hallucinogens and antipsychotic medications. Also called abuse liability.