Schedule induction and overindulgence.

An animal model of human alcoholism is presented in which animals maintain chronic overdrinking to the extent that they develop severe physical dependence. They can be induced to overdrink ethanol in situations where an alternative fluid is present as well, so that the overindulgence is elective. The environmental conditions that produce this result also can induce the overingestion of other substances, aggression, and hyperactivity. It would appear, then, that many kinds of seemingly excessive, maladaptive behavior in animals and humans can have similar environmental sources. Alcoholism may be viewed within a context of environmental conditions that can produce a variety of excesses.