APA Dictionary of Psychology

a type of treatment that involves deliberately weakening the organism and thereby (it is supposed) depleting it of some substance believed to be harmful, as by bleeding, purging, blistering, or making the patient vomit. Depletive treatment originated in the time of Greek physician Hippocrates (c. 460–c. 377 bce) and was practiced for many centuries. More recently, certain psychiatric disorders have been treated by depletive therapies, as in various shock therapies.