Samuel B. Guze. 147 pages. New York: Oxford University Press; 1992. $24.95.

In 1979 I decided to leave internal medicine and begin a residency program in psychiatry. I was confronted by colleagues who asked how I could leave internal medicine to enter a field without white coats, without discipline, and without a coherent model of disease. Most of my medical colleagues believed that psychiatry was certainly not a branch of medicine. Fortunately, Samuel Guze had already started writing his thoughts about the field of psychiatry. Now we have the monograph Why Psychiatry Is a Branch of Medicine, a synthesis of Guze's distinguished writing career and reflections about the nature of psychiatry and the fact that psychiatry follows the same paradigm as other medical specialties.

Guze discusses the concept of disease, including in the definition the fact that our understanding of disease changes with advances in medical knowledge. Guze continues with an explanation of the medical model and the fact that the same underlying assumptions apply to psychiatry as to the rest of medicine: 1) Different disorders have different causes, different epidemiologic characteristics, and different pathophysiologic mechanisms; 2) Different diseases respond to different interventions; and 3) Improvement in diagnosis and treatment depends largely on advances in biomedical knowledge. Although the sociocultural, the psychodynamic, and the behaviorist models compete with the medical model, they do not offer its comprehensiveness.

An acceptance of the medical model leads to the recognition that diagnosis and differential diagnosis are central in psychiatry as a means of classification and communication. Guze cites his work from 1970 to 1990 about the importance of diagnosis to predict cause, pathogenesis, course, response to treatment, and associated familial psychological disease.

Guze defines biologic psychiatry as "perhaps the inevitable outcome of following the medical model". He refers to his 1989 work that noted that biologic psychiatry has provided psychiatry with "the most comprehensive and inclusive framework for dealing with psychiatric illness". He warns that, just as in other fields of medicine, culture, socioeconomic circumstances, ethical considerations, and religion cannot be overlooked.

Does a place for psychotherapy exist if one views psychiatry from the perspective of the medical model? Guze defines a rehabilitative psychotherapy that makes no assumptions about cause or pathogenesis. Its purpose is to help the patient develop a better understanding of a problem and an approach to minimize difficulties associated with the problem. Guze opines that the rehabilitative strategy is compatible with the medical model in the same way that good medicine must involve more than making a diagnosis and prescribing appropriate medication.

Philosophical issues in psychiatry relate to questions about the meaning of illness, the relation of mind to body, and the professional and ethical responsibilities of a physician caring for the patient with a psychiatric disorder. One conclusion of viewing psychiatry within the context of the medical model is the unacceptability of accepting a personal meaning for illness as a substitute for knowledge concerning cause and pathogenesis.

Guze concludes with a statement of his purpose: "to articulate as clearly and effectively as possible a strategy for thinking about psychiatric disorders". His book accomplishes this mission. It is important reading for the general medical community as well as for psychiatrists who are struggling to establish a medical identity. The bibliography includes 16 references to works Guze has published from 1963 to 1990. We are privileged to have the opportunity to read a synthesis of Guze's thinking, which has been in the forefront of psychiatry.