Pavlovian conditioning and heroin overdose: Reports by overdose victims

A Pavlovian conditioning model of tolerance emphasizes the contribution of an association between predrug cues and the systemic effects of the drug to tolerance. In agreement with the model, results of a recent animal experiment indicate that the lethal effect of heroin, in drug-experienced rats, is influenced by the cues associated with its administration. To assess the applicability of these findings to instances of heroin overdose in humans, overdose survivors were questioned about the circumstances of their overdose. These retrospective reports by human victims are congenial with these animal data, and suggest that the conditioning model may be relevant to some instances of overdose death among heroin addicts.