400 BOOK REVIEWS

is no evidence for social influence acting directly to induce a food aversion. Rozin and Zellnerdiscuss the role of associations between flavors and postingestional consequences, and betweenflavors and other flavors, in the development of preference and liking in humans and otheranimals. They also speculate about the role of Pavlovian conditioning in establishing some itemsas disgusting or contaminated.

In part four, "Pharmacological and toxicological assessments using conditioned foodaversion methodology", Gamzu, Vincent and Boff assert that no common property of agentswhich induce CTAs has been identified, e.g., they are not all emetics, nor do they all have the sametherapeutic effect in man. Siegel suggests that meaningful subclasses ofagents might emerge fromthe use of measures other than intake, e.g., orofacial responses to infused liquids. Riley and Tuckdiscuss how the basic CTA procedure might be modified to make it a more effective index ofdrugtoxicity. Ader uses the CTA procedure to elicit conditioned immunosuppressive responses, andsuggests how conditioning might be useful in improving pharmacotherapies. Pairing an internalstate, e.g., that produced by some drug, with illness would seem to be a promising way to makethat state aversive. Revusky found that, on the contrary, such drug-drug conditioning actuallyreduced the sickness evoked by the first drug, i.e., that there was a conditioned antisicknessresponse. He discusses the possible clinical implications of this discovery.

In the last section, "Applications of conditioned food aversion methodology", Logue reviewsretrospective data on the incidence and objects of CTAs in humans. Nathan discusses somerelatively successful chemical aversion therapies for the treatment of alcoholism. Gustavson andGustavson describe several instances in which the use of CTA methodology in the control ofpredators is complicated by social interactions among the predators, and suggest that we bringsome of the added complexity of the natural world into the laboratory. In .separate chaptersSmith and Bernstein discuss CTAs that arise during cancer chemotherapy or radiation therapy.Bernstein describes an animal model for these aversions which differs from the standard CTAprocedure in allowing rats continuous access to a novel diet for several days prior to thebeginning of a series of treatments. This procedure produced strong aversions, especially toprotein sources. Bernstein also demonstrates that at least some tumor anorexias are largely theresult of conditioned food aversions.

Edited books with many, necessarily brief chapters often suffer from a prose style that is socompressed that the chapters verge on lists of allusions to other papers. With rare exceptions, thepresent chapters avoid that problem; the authors and editors are to be commended for using thelimited space to the best advantage. This book should be useful to those seeking informationabout the phenomena of food aversion learning or the clinical and medical use ofCTAs for yearsto come.

Vincent M. LoLordoDepartment of Psychology,

Dalhousie University, Halifax

Nutrition and the brain, Volume 7: Food constitutents affecting normal and abnormal behaviours.R. J. Wurtman and J. J. Wurtman (Eds.). Raven Press, New York, 1986. Pp.253, $59·50.

Over 15 years have passed since Richard Wurtman and his colleagues began publishingevidence that manipulations of dietary amino acids, particularly tryptophan, appear capable ofmodifying the metabolism of certain brain neurotransmitters and behavior. Since then, there hasbeen a steady accumulation of both basic and clinical work on this topic which is widelyperceived as validating the old adage "You t are what you eat". This latest volume in theWurtmans' series provides six reviews of widely varying scope which continue in this tradition.As in several of the preceding volumes, a major focus is clinical.

The first chapter by B. Spring summarises a'host of investigations aimed at determining theimportance of dietary factors to human performance, perception and mood in both normal andpathological conditions (e.g., hyperactive children). Also included is an overview of research

BOOK REVIEWS 401

designs and their importance to outcome and interpretation. Despite some interesting parts, thisambitious undertaking becomes rather boring due to its length and occasional superficiality.

The second chapter by S. N. Young is a solid account of important pharmacological andmetabolic factors which pertain to clinical studies using tryptophan. This experienced, well­known investigator skilfully guides his readers through selected animal and human literature onthe topic. Young concludes that while there remain many questions about the uses and impact oftryptophan, existing evidence is compelling enough to warrant its further investigation. Thissensible and scholarly review is worth reading.

The next three chapters deal with more specific clinical psychopathologies. H. M. van Praagand C. Lemus review rationales for and outcomes from the use of catecholamine andindoleamine precursors in the treatment of schizophrenia and mood disorders. They also touchon the potential utility of indoleaminergic manipulations in aggressive and arousal disorders.The first author is wellknown for his intensive work and expertise in this field, having providedmany authoritative reviews on this topic over the past ten years. The current version continues inthe same genre, providing an update and synthesis of this work. The next chapter by N. E.Rosenthal and M. M. Heffernan examines the potential relationships between bulimia,carbohydrate craving and mood. They hypothesize that a link may exist within the CNS thatbonds these states to one another. However, as pointed out by the authors, there is little directevidence to support this contention. The take-home message is that researchers studyingaffective disorders should heed abnormalities of eating in their patients, as they may signaldifferent biological underpinnings for mood pathology. The last of these three chapters is byK. M. Pirke and D. Ploog. As in previous reviews, they focus on eating and starvation factors inanorexia nervosa, with some comments on bulimia. From their and others' research, it appearsthat many of the metabolic anomalies found in such patientsare consequences rather than causesof the illness.

The final review departs considerably from the others, but to me is the finest. W. M. Pardridgeprovides a superb assessment of the popular but controversial artificial sweetener, aspartame,from the standpoint of potential toxicity and CNS effects. Drawing on his expertise ofmechanisms affecting blood-brain barrier processes, Pardridge concludes that (a) any potentialeffects of high doses are mediated by phenylalanine, and (b) aside from high-risk groups (i.e.,developing fetuses, seven- to twelve-year-old children, or patients with phenylketonuria),moderate (8-10 rug/kg/day) intake is unlikely to affect the brain. However, he cautions that theremay be subtle CNS effects which are not detectable clinically, indicating a continued need toclarify the benefits versus risks of this substance.

As in the past, the publisher has done a nice job of assembling the volume. Each reviewcontains worthwhile elements. However, the broad scope of topics renders it useful for specialistsrather than generalists. Viewed as a whole, the evidence summarised continues to support thepossibility that "You are what you eat". But, given the many uncertainties and caveats in thisemerging field, it might be more appropriate to modify the dictum to: "You may be what you eat,but at times you eat because of what you are!"

Donald J( CoscinaClarke Institute of Psychiatry, Toronto, Ontario