Pathophysiological effects of cocaine in humans: review of scientific issues

Almost all data on pathophysiological abnormalities associated with human cocaine use comes from clinical observation and testing of cocaine abusers seeking treatment. Such data are subject to several confounding factors which preclude drawing definitive conclusions about the pathophysiological mechanism for the observed abnormality, its prevalence and prognosis, and individual differences in susceptibility. Confounding factors include the unknown purity of cocaine used, uncertainty as to quantity and duration of cocaine exposure, effects of other substances frequently used by cocaine users, abnormalities associated with drug route of administration and the drug abuse lifestyle, and selection bias. Future studies can address these issues by employing more sophisticated research designs, such as prospective, longitudinal follow-up of large, representative samples of cocaine users, case-control comparisons of well characterized cocaine users with appropriately matched groups, and experimental administration of cocaine under safe, controlled conditions.