Neuropsychiatry

Introductory Approach to Neuropsychiatry

File photo. Credit: Austin Journal of Neuropsychiatry & Cognitive Science  Opens in new window Neuropsychiatry may be defined as the study and treatment of cognitive, emotional, and behavioral problems caused by neurologic disorders.

While this definition of neuropsychiatry accurately captures the clinical and research interests of many modern neuropsychiatrists, the field is more broadly and fully defined as:

Neuropsychiatrists subscribe to the philosophical position that mental states are brain states. As such, all disturbances of cognition, emotion, and/or behavior reflect brain disturbances. In this view, psychiatric illnesses are by definition neurologic illnesses.

Additionally, it is further understood that many neurologic illnesses will entail disturbances of cognition, emotion, and behavior.

Followed to its extreme, this definition suggests that any categorization of brain disorders as either exclusively neurologic or psychiatric is, at best, arbitrary.

By extension, this definition suggests that psychiatry and neurology are themselves two somewhat arbitrarily defined divisions of the much broader medical specialty, neuropsychiatry.

This very broad and inclusive definition of neuropsychiatry, or other similar versions of it, is often met with skepticism and resistance among both psychiatrists and neurologists.

Although modern psychiatrists are increasingly mindful of the biological bases of mental illness, most do not consider themselves neuropsychiatric sequelae of neurologic conditions (e.g., stroke, dementia Opens in new window, multiple sclerosis, etc.), but do not typically consider themselves experts in either the study or treatment of neuropsychiatric problems.

Indeed, many clinicians in both specialties continue to make the distinction between disorders that are “organic” and those that are “functional,” and regard the former as the province of neurology and the latter as the focus of general psychiatry Opens in new window.

Certainly, this distinction facilitates referral to the physician whose training and experience are most likely to best serve patients — those with schizophrenia Opens in new window are best treated by psychiatrists, and those with strokes are best cared for by neurologists. However, the recent decades of basic and clinical neuroscience research make clear that the distinction between psychiatric and neurologic conditions is not as unambiguous as has been presumed during most of the twentieth century.

Further, it is becoming increasingly clear that neither specialty alone, at least insofar as they have been traditionally practiced, provides a framework in which the broad range of problems experienced by so many of our patients can be fully understood or optimally treated.

For example, older patients with depressed mood Opens in new window may be in the early stages of a dementing illness — if the depression Opens in new window is the focus of treatment and the patient remains under the care of a general psychiatrist, will this result in optimal evaluation and treatment of the dementia Opens in new window as it progresses?

If the patient is instead referred to a general neurologist, will the depression (including its impact on the patient’s family) be optimally managed?

What if electroconvulsive therapy for the dementing patient’s treatment-resistant depression is indicated — who now is the best physician for the job?

Similarly, if schizophrenia Opens in new window is indeed a disorder of impaired cognition (as has recently been suggested by many experts in the field), is it still a psychiatric disease, or is it now a neurologic disease?

Who is best suited to care for these patients if the early (and fundamentally neurological) formulation of this problem, namely dementia praecox, turns out to be the most correct one?

If it is true that mental states are brain states, and therefore all disorders of cognition, emotion, and behavior are brain disorders, then dichotomizing brain disorders into those that are psychiatric and those that are neurological is indeed both arbitrary and artificial.

History shows us that this dichotomization occurred relatively recently, as did the division of neuropsychiatry into the subdisciplines of psychiatry Opens in new window and neurology.

It also may be suggested that these divisions are better explained as consequences of sociopolitical and medicopolitical forces than as the logical consequence of a valid and sound scientific thesis.

A brief review of this history, beginning with the early origins of mind–body and mind–brain dualism and proceeding to the twentieth century, may permit a clearer understanding of how this schism between psychiatry and neurology developed.

With this history understood we hope to encourage you to reconsider the traditional divisions between these specialties and the various disorders to which they lay claim. From the new perspective on neuropsychiatry that this review provides, we invite you to begin to engage in the study and treatment of your patients using the introductory approach to neuropsychiatry presented in this literature.

A Brief Historical Perspectives

Although philosophers and physicians have long debated the nature of mind: whether it is spiritual (nonmaterial) or physical (material), resolution of this debate has been hampered by the lack of a technology of sophistication sufficient to permit scientific study of this problem.

Many early philosophers believed that the body was infused with “vital spirits” which, when not present in the appropriate form or amount, produced mental and physical infirmity. Plato (fourth century BC) was an early advocate of this position, and in Phaedrus describes madness as:

a divine release of the soul from the yoke of custom and convention … prophetic, initiatory, poetic, [and] erotic.Plato (fourth century BC)

Interestingly, although Plato is often referred to as an early mind-body dualist, it is not clear that his philosophy was entirely that of substance dualism. In the same passage from Phaedrus where he seemingly advocates a dualist position, he also describes another form of madness, one “produced by human infirmity,” and ostensibly related to problems of the body–brain.

Less ambivalent on this issue, Democritus (fourth century BC) offered a fundamentally materialist notion of the mind, claiming that since the world consists of nothing more than atoms and the void, the mind is simply a remarkably organized collection of atoms.

Similarly, Hippocrates (fourth century BC) rejected entirely the notion of a divine origin of mental illness, stating his position quite clearly in On the Sacred Disease:

Men ought to know that from nothing else but the brain come joys, delights, laughter and sports, and sorrows, griefs, despondency, and lamentations … All these things we endure from the brain.Hippocrates (fourth century BC)

However, without the scientific methods or tools needed to investigate these brain–behavior relationships, early philosophers and physicians were unable to make any definitive attributions of mental function to brain function.

Early western religions also subscribed to a version of Platonic mind–body dualism, making the mind indistinguishable from the soul. Since the soul was the province of the Church, it was therefore excluded from the realm of acceptable philosophical and scientific inquiry.

In this context, such inquiries were potentially heretical and dangerous, and consequently there was little in the way of philosophical or medical dissent from the traditional dualist perspective for many centuries.

Restoring the study of brain-behavior relationships as an acceptable field of philosophical and scientific inquiry was accomplished almost single-handedly by Descartes (1596–1650).

In A Discourse on Method, Descartes asserted that the brain is simply the material “machine” through which the non-physical mind–soul operated. In this light, the brain is simply another body part to be studied, and though the elements of the brain might be associated with certain functions of the mind, the operations of the brain are not equated with the mind itself.

In this fashion, Descartes offered a solution to the mind–body problem that simultaneously preserved religious notions of freewill, moral agency, and the soul and permitted investigation of the brain as the machine through which the mind operated in the physical world.

The historical importance of Descartes’ work cannot be overstated, and must be recognized for its instrumental role in the genesis of neuropsychiatry. Indeed, in the remainder of the seventeenth century neuropsychiatry began to emerge as a distinct specialty, with the alienists as its practitioners, and began focusing on the humane treatment of the insane.

However, while Descartes’ dualist solution to the mind–body problem permitted humane treatment of those whose mind “machine” had malfunctioned, it nonetheless excluded from science any serious inquiry into the essential nature of the mind and mental processes, relegating such inquiries to philosophy and theology.

Despite Descartes’ work and the societal/religious orthodoxy of the time, many Renaissance era neuropsychiatrists remained committed to the thesis that mental states are brain states, and that aberrations of mental functioning are the products of a disordered brain.