Book Review
Addictions 
Marijuana and Madness David Castle, Robin Murray, editors. Cambridge (UK):
Cambridge University Press; 2004. 218 p. US$80.00
Reviewer
rating*: Excellent
Review by: Nady el-Guebaly, MD
Calgary, Alberta
Should marijuana be decriminalized, legalized, medicalized, or otherwise liberalized? In the struggle to determine how best to manage the growing use of marijuana by many segments of our Canadian population, the enthusiastic endorsements of consumer groups are matched by dire predictions of doom if marijuana’s current illegal status changes. The debate involves physicians, including psychiatrists, in various potential roles ranging from prescribing the medication to caring for those suffering from the health consequences of marijuana use. In that context, a state-of-the-art review of the empirical evidence focusing on the mental health implications of marijuana use is indeed welcome.
The editors are leading researchers. David Castle is a professor at the Mental Health Research Institute and University of Melbourne, Australia, while Robin Murray is a professor at the Maudsley Hospital and Institute of Psychiatry, London, England.
The text is divided into 13 chapters, 8 of which are devoted to the association of marijuana use with psychosis. The introductory chapter by Raphael Mechoulam, who first identified the Delta(9)-THC psychotropic constituent in 1964, reviews the discovery of endocannabinoids and the CB1 and CB2 receptors and predicts the discovery of additional endocannabinoids and receptors rather than additional plant constituents. Leslie Iverson presents a complementary update of the animal studies mapping out the anatomical distribution of these receptors and their physiological effects. The interaction between cannabinoid and opioid systems is a promising area of investigation.
The next 2 chapters address the psychomimetic effects of cannabis on humans. David J Castle and Nadia Solowij provide a synopsis of the effects of cannabis intoxication as well as of the putative “amotivational syndrome.” Louisa Degenhardt and others follow with a thoughtful discussion of the mixed results arising from studies of the comorbidity between cannabis use and depression. Standardized measurements, longitudinal studies across the life cycle, and twin studies are called for.
In the first chapter dealing with psychosis, Hélène Verdoux supports the hypothesis that cannabis may be an independent risk factor for psychosis, at least in subjects with a preexisting vulnerability for such a disorder. Next, Wayne Hall and Louisa Degenhardt conclude from a few controlled clinical studies that, while it is plausible that high dosages of cannabis can produce psychotic symptoms, there is no compelling evidence for a syndrome of “cannabis psychosis.”
Louise Arseneault and others follow with a comparison of 3
prospective studies: the Swedish conscript cohort, the Netherlands Mental Health Survey and Incidence Study and the Dunedin Study in New Zealand. They conclude that cannabis use is part of a complex constellation of component causes, including genetic predisposition, that lead to the development of schizophrenia. Don Linszen and
others further examine the dosage-related impact of cannabis abuse on the course of schizophrenia. Patients with schizophrenia with
particularly heavy cannabis use do suffer more relapses as well as more florid psychotic and disorganization symptoms.
This series of clinical chapters is complemented by Suresh Sundram’s preliminary neuroscientific survey of potential changes in endogenous cannabinoid systems in patients with schizophrenia. D Cyril D’Souza and others explore the possibility that the induction of Delta(9)-THC transient schizophrenia-like symptoms in healthy individuals provides preliminary support for a laboratory-based cannabinoid “model” psychosis. This chapter is the first originating from US-based authors.
Next is Catherine Spencer’s review of the intriguing motives behind the use of cannabis among individuals with psychotic disorders. These motives, which are similar to those of individuals without psychotic disorders, include the following: enhancing affect, coping with negative affect, and enhancing social affiliation. Less common but more specific reasons include coping with positive symptoms or medication side effects. Of particular interest to clinicians is Wynne James and David J Castle’s outline of an assessment protocol for cannabis use in persons with psychosis as well as a stepped approach toward treatment integration.
In the last chapter, Harrison Pope and Deborah Yurgelun-Todd cautiously review the specter of irreversible cognitive deficits in individuals with either very long exposure and (or) very early exposure to the drug.
The main positive features of this book are its timeliness and scholarly analyses of various controversial associations between psychosis and cannabis use. Overall, the Australian contributions are well represented, but comparatively, the North American contributions may be less so. The chapters are stylistically uneven, as is common in multiauthored books. Some chapters are more difficult to read than others, depending on one’s background. As well, the absence of a concluding summary by the editors is disconcerting; I would have appreciated a concluding chapter wrapping up the current information. Nevertheless, I highly recommend this book to all clinicians who wish for an update on the many intriguing questions about cannabis use and mental health raised by our colleagues, our patients, and the public. I cannot think of a better reference at this point. A softcover edition would reduce the cost of the book somewhat.
*Reviewer
Rating Scale/ Échelle d’évaluation du réviseur
Excellent / Excellent
Very Good / Très bon
Good / Bon
Fair / Passable
Not recommended / Pas recommandé
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