"The dead drug leaves a ghost behind. At certain hours it haunts the house," Jean Cocteau once wrote. In The Ghost in the Addict, Shepard Siegel offers a Pavlovian analysis of drug use. Chronic drug use, he explains, conditions users to have an anticipatory homeostatic correction, which protects the addict from overdose. This drug-preparatory response, elicited by drug-paired cues, is often mislabeled a "withdrawal response." The withdrawal response, however, is not due to the baneful effects of previous drug administrations; rather, it is due to the body's preparation for the next drug administration--a preparatory response that can haunt addicts like a ghost long after they have conquered their usage.

Examining the failure of legislation, the circumstances of overdose, and the cues that promote drug use, Siegel seeks to counter the widespread belief that addiction is evidence of a pathology. Instead, he proposes that the addict has an adaptive, learned response to the physiological changes wrought by drug use. It is only through understanding so-called withdrawal symptoms as a Pavlovian response, he explains, that we can begin to understand why addicts experience cravings long after their last drug use.