The Long-Term Behavioral and Neurobiological Consequences of Treatment with Psychomotor Stimulant Drugs: Implications for Psychopathology

Abstract

When psychoactive drugs are administered repeatedly many of their effects change, and these changes take two main forms: tolerance or sensitization. The sensitization produced by the repeated administration of psychostimulant drugs, such as amphetamine or cocaine, has attracted considerable attention recently, for two major reasons. First, psychostimulant sensitization is an interesting example of experience-dependent plasticity, whereby very persistent changes in behavior occur as a function of past experience — in this case, past drug experience. Thus, the phenomenon provides an interesting model to explore the nature of neuroplastic adaptations underlying experience-dependent changes in behavior. Second, psychomotor stimulant drug-induced sensitization is thought to provide an animal model for studying some forms of drug-induced psychopathology. These include the development of paranoid schizophrenic-like symptoms often seen with repeated exposure to amphetamine or cocaine (Post, 1975; Segal et al., 1981; Robinson and Becker, 1986), as well as the compulsive patterns of drug-seeking behavior that characterize the development of addiction (Robinson and Berridge, 1993). The purpose of this chapter is to briefly review some recent advances in our understanding of this phenomenon.