Abstract and Introduction
Abstract
Fossil records showing trephination in the Stone Age provide evidence that humans have sought to influence the mind through physical means since before the historical record. Attempts to treat psychiatric disease via neurosurgical means in the 20th century provided some intriguing initial results. However, the indiscriminate application of these treatments, lack of rigorous evaluation of the results, and the side effects of ablative, irreversible procedures resulted in a backlash against brain surgery for psychiatric disorders that continues to this day. With the advent of psychotropic medications, interest in invasive procedures for organic brain disease waned.
Diagnosis and classification of psychiatric diseases has improved, due to a better understanding of psychiatric patho-physiology and the development of disease and treatment biomarkers. Meanwhile, a significant percentage of patients remain refractory to multiple modes of treatment, and psychiatric disease remains the number one cause of disability in the world. These data, along with the safe and efficacious application of deep brain stimulation (DBS) for movement disorders, in principle a reversible process, is rekindling interest in the surgical treatment of psychiatric disorders with stimulation of deep brain sites involved in emotional and behavioral circuitry.
This review presents a brief history of psychosurgery and summarizes the development of DBS for psychiatric disease, reviewing the available evidence for the current application of DBS for disorders of the mind.
Introduction
In The Cure of Folly (c. 1475–1480), Hieronymous Bosch depicts what is touted as the first great artistic representation of neurological surgery. The surgeon, wearing what resembles a dunce cap, operates on the cranium of his hapless patient, who exhorts him to "dig out the stones of my folly." Subsequent work in the 15th and 16th centuries depicts surgeons cutting for stones in patients' heads to cure mental illness, but whether this represented contemporary mental health practices or merely commentary on the plight of patients at the mercy of medical malfeasants remains debatable. Nevertheless, this painting recapitulates the tensions underlying the increasing interest in neurosurgery for psychiatric illness today: the desire to affect human behavior and consciousness through physical action on the brain; the hope of treating or curing disabling illness by such action; the uncertainty regarding the underlying physiology, safety, and efficacy of such interventions; the willingness of the patient to undergo procedures with dubious benefit when no other effective treatment is available; and the popular perception of those performing and undergoing such procedures.
The cost of psychiatric illness justifies addressing these difficult issues. Across the world, neuropsychiatric disease is the most important cause of disability, accounting for in excess of 37% of all healthy life-years lost to disability. In fact, depression is the single leading cause of disability in both males and females, affecting 10%–15% of the population. Notably, between 50% and 66% of treated patients do not respond fully to medical therapy alone, requiring additional psychosocial interventions, and between 10% and 30% of patients are resistant to multiple classes of treatment. In the US, more than one-quarter of the population at large has a mood, anxiety, or substance abuse problem. Faced with this disease burden, enthusiasm for a surgical treatment for psychiatric disease is understandable—if the procedures are safe and effective.
With the increasing recognition of the burden of psychiatric disease there is a concomitant increase in interest in the development of safe and efficacious surgical treatment of that subset of patients who remain refractory to medical treatment. Psychosurgery has endured popular backlash after indiscriminate application in the face of dubious efficacy in the first half of the 20th century. Compared with the imprecise destructive procedures of that era, DBS has the advantages of being precisely targeted, relatively minimally invasive, essentially reversible and nondestructive, and adjustable with respect to stimulation parameters. This article examines the growing body of evidence for the application of DBS technology in the treatment of psychiatric disease (Fig. 1).
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Figure 1.
Schematic showing locations of common targets of DBS for psychiatric disease, with indications, in parasagittal, axial, and coronal sections. GPe = GP externus. Copyright Andrew J. Rekito. Published with permission.