Factors controlling drug reinforced behavior.

An overview is provided of factors controlling drug reinforced behavior. Drug reinforced behavior is defined, and control procedures for rigorously identifying such behavior are discussed. Factors affecting drug reinforced behavior include the drug itself, animal species, route of administration, current circumstance variables, subject's experimental history, and response consequences. Current circumstance variables concern conditions present during opportunities for drug self-administration and include such factors as stimulus control, food deprivation, drug-access conditions, and brain lesions. Response consequence variables include reinforcement schedule, punishment, drug dose, and competing reinforcers. Drug reinforced behavior is a member of a more general class of behavior, namely operant behavior. Over the last 25 years there has been a rapid increase in understanding drug reinforcement, and this pattern of expanding knowledge suggests that the high rate of progress will continue.