The Interface of Cannabis Misuse and Schizophrenia-Spectrum Disorders

Abstract

This chapter provides an overview of the complex ways in which cannabis misuse intersects with schizophrenia-spectrum disorders. The centrally active constituents of Cannabis sativa are discussed, and the central endocannabinoid system is briefly reviewed. Information on cannabis use and misuse in the general population is provided, including the prevalence of use in general population samples and consequences of such use. Findings pertaining to cannabis misuse among individuals with schizophrenia-spectrum disorders are presented, along with an overview of the adverse effects of cannabis use in terms of symptoms, neurocognition, age at onset, and various aspects of the long-term course and outcomes. A discussion of the literature that suggests that cannabis use is a component cause of, or independent risk factor for, psychosis is given. Other potential mechanisms for the association are considered, including psychosis causing cannabis use or the existence of a shared diathesis that underlies both. To evaluate the literature suggesting that cannabis use, especially in early adolescence, is a component cause of schizophrenia-spectrum disorders, nine criteria for establishing causality are summarized. The chapter concludes with a brief discussion of treatment implications for clinicians and program developers, as well as prevention implications for researchers, public health officials, and policy-makers. PU - SPRINGER PI - DORDRECHT PA - PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS