ArticlesComorbidity: Cannabis and ComplexityRAPHAEL, BEVERLEY MD; WOODING, SALLY PhD; STEVENS, GARRY M Clin Psych JASON CONNOR, PhD Author Information RAPHAEL, WOODING, and STEVENS: Centre for Mental Health, NSW Health, Department, North Sydney; CONNOR: Department of Psychiatry, The University of Queensland, Princess Alexandra Hospital, Brisbane, Australia. Please send correspondence and reprint requests to: Beverley Raphael, MD, Director of Centre for Mental Health, NSW Health Department, Locked Mail Bag 961, North Sydney 2059, Australia. Journal of Psychiatric Practice 11(3):p 161-176, May 2005. Buy Abstract Cannabis is one of the most commonly used illicit drugs, and its effects have traditionally been seen as less harmful than outcomes associated with the highly prevalent use of alcohol and other illicit substances (e.g., cocaine and amphetamines), and injecting drugs. Consequently, less attention has been focused on developing and evaluating interventions in this area. However, current research supports the idea that cannabis does pose a number of acute and chronic health risks to the individual and to society. The authors review findings concerning the physiological and neurological effects of cannabis, prevalence of use, and studies concerning its possible role as a "gateway" drug. Diagnostic criteria for cannabis dependence and abuse are discussed, with a focus on whether a cannabis withdrawal syndrome exists and if so how it can be diagnosed. There is strong support for a link between cannabis and the development and exacerbation of psychosis and other mental health conditions (e.g., anxiety, depression). Further research is needed to determine the underlying neurochemical processes and their possible contribution to etiology, as well as the social factors that contribute to the increasing use of cannabis by young people. In addition there is a need for systematic evaluation using randomized controlled trials to determine effective prevention and treatment strategies. A number of public health programs that address cannabis use are reviewed along with available evidence for their effectiveness. Copyright © 2005 Wolters Kluwer Health, Inc. All rights reserved.