Gordon Claridge and colleagues use this book as a platform from which to explore the boundaries of psychosis, which they argue are situated on a continuum with normal behavior and experience. This volume includes a compendium of chapters ranging from rather specialized discussions of such concepts as latent inhibition and cerebral lateralization to more freewheeling discussions of spiritual experiences and creativity in relation to schizotypy. Schizotypy is a book to be sampled and explored by those interested in this concept and the provocative questions the authors raise. Some clinicians may find some of it too abstruse or too peripheral to their clinical concerns, but those who are intrigued by the central theme will likely find it of value.

The central dilemma, addressed by Claridge at the outset, is that “schizotypy” is a rather specific term that is unambiguously associated with schizophrenia in its current usage. The terms used by Claridge and the chapter authors, however, appear to be more related to psychoticism. The choice of schizotypy fits well with some of the research literature that is presented, but the multidimensional approach espoused by the authors suggests that schizotypy consists of a number of dimensions, including psychoticism, negative schizotypy (marked by social withdrawal), and cognitive disorganization. Psychotic-like phenomena are the least specific aspect of schizotypy because they can extend from schizophrenia and bipolar disorder to other psychotic disorders, dyslexia, drug-induced states, and different forms of delirium. Yet, it is the rather quieter and sometimes more subtle social deficit symptoms that seem particularly specifically related to schizophrenia. At a time of intense interest in investigating the prodrome and endophenotypes related to schizophrenia, it is helpful to be reminded of this distinction. For example, Richardson reminds us in her chapter on dyslexia in schizotypy that psychotic-like symptoms can be common in dyslexia with no predictive power for a diagnosis of schizophrenia.

It may be that the dichotomies among organic, psychological, and psychobiological paradigms raised by Claridge are remnants of an era when our understanding of the implications of differences in brain function was much more primitive. There is no doubt that there is a very real component to both the altered biology and the psychology of the schizophrenia spectrum. In distinguishing schizophrenia from Alzheimer’s and other neurological diseases, however, Claridge states, “There is no evidence that schizophrenia leads to any cognitive impairment (in the dementing sense) or indeed to any impairment that cannot be explained as a secondary consequence of other factors,” which belies data suggesting that at least a substantial proportion of subjects with schizophrenia may have cognitive impairment very similar to dementia, especially in their elderly years. Indeed, milder forms of cognitive impairment are now recognized as an essential construct in understanding schizophrenia.

I, for one, would have been more comfortable with the contents of this book if it were more oriented to psychosis-related traits, because these seem to be the backbone of the book. The academic discussions are somewhat uneven, and some material is dated, but, in general, the volume would be of interest to psychologists, psychiatrists, and other mental health professionals who are interested in the boundary between normalcy and psychotic disorders such as schizophrenia. Claridge’s concluding remarks are thought provoking, and possibly the main disappointing aspect of this volume is the limited scope of the contributions of Claridge himself, whose Origins of Mental Illness(1) represented one of the most scholarly and penetrating analyses of the relationship between normalcy and mental illness in language that nonresearchers and even the educated lay public could understand. I hope, however, that the book will be read as a challenge to strictly deterministic models of illness as the authors call attention to the continuities between the altered states and traits we associate with normalcy and psychotic phenomena.