Psychiatry's Holy Grail: The Search for the Mechanisms of Mental Diseases

Psychiatry's Holy Grail: The Search for the Mechanisms of Mental Diseases * Gerald N. Grob (bio) "The truth," Dr. Oliver Wendell Holmes wrote nearly 150 years ago, "is, that medicine, professedly founded on observation, is as sensitive to outside influences, political, religious, philosophical, imaginative, as is the barometer to the changes of atmospheric density." 1 The accuracy of the venerable physician's perceptive statement is particularly well illustrated in the evolution of American psychiatric thought since the early nineteenth century. In analyzing the development of concepts of mental illnesses, I should like to begin with a broad generalization. As human beings we generally inhabit two different worlds simultaneously. The first is characterized by contingency, indeterminacy, and an inability to comprehend or control the numerous variables that shape our environment; our judgments, analyses, and actions often represent a pragmatic response to a seemingly intractable and partially incomprehensible universe. The second is an imaginary and idealized world—one characterized by certainty and clarity, and where pure and precise knowledge leads to a kind of understanding that enables human beings to cope with or solve perennial problems. The static nature of this idealized world fosters the illusion that the creation of a veritable utopia is within reach. [End Page 189] The above metaphor, however simplistic, is equally applicable to medicine generally and to the specialty of American psychiatry. As clinicians, psychiatrists were compelled to deal with individuals whose pathology was rarely amenable to therapeutic clarification or simple prescriptions. At a quite different level, psychiatrists provided elaborate theoretical explanations of the nature and etiology of mental disorders. These explanations generally encompassed a blend of psychological, environmental, physiological, and genetic factors, although the relative importance of each changed over time. Successive generations perceived their own explanations to be closer approximations to truth. If theories were not immediately verifiable by empirical data, they were justified by the claim that in the near future it would be possible to cross a ubiquitous threshold and arrive at a full understanding of those mental disorders that have plagued humanity since the beginnings of recorded history. In offering such a simplified caricature, I do not mean to denigrate psychiatry in particular or medicine in general. Many disciplines—whether in the physical, natural, social, or behavioral sciences—have similar characteristics: their members are invariably committed to a search for final and irreducible truths. The need to provide overarching explanations, moreover, is a function not only of the internal dynamics of disciplines. On the contrary, all societies demand explanations to account for the unexpected or abnormal. Like their brethren within medical practice, psychiatrists traditionally provided both an explanation for abnormal behavior and a rationale for treatment and prevention. Had they rejected such a role, they might have impaired their professional legitimacy and prepared the way for other groups willing to meet perceived social needs. Oddly enough, the relationship between theory and practice was tenuous at best. The theoretical formulations of psychiatrists were not always linked with their role as clinicians. Practice tended to be pragmatic and eclectic; many psychiatric therapies were but modifications of traditional medical practices. Theory, by contrast, was more closely related to broader intellectual, cultural, and social currents. 2 In this brief paper I should like to survey psychiatric formulations of the nature and etiology of mental disorders since the early nineteenth century (while partly ignoring clinical practice), and to identify four distinct chronological periods (1820–70, 1870–1940–1940–70, 1970 to the present), each with its own distinctive style. The psychiatric models [End Page 190] characteristic of each of these periods differed in significant ways. Yet the differences were generally ones of degree; they were rarely mutually exclusive. Indeed, explanations of mental illnesses generally vacillated between two polar extremes: between environment (broadly defined) and heredity; and between somatic and psychogenic. To be sure, the majority of psychiatrists tended to be eclectic. Nevertheless, they often expressed preferences for one extreme or the other. Over time these preferences underwent subtle shifts, as the social and cultural context in which they were articulated changed. I should also like to emphasize the importance of the psychiatric faith in medical progress, which was synonymous with the belief that a steadily expanding knowledge...