Book Review

Neurobiology of Violence

N Engl J Med 1995; 333:1653December 14, 1995

Article

Neurobiology of Violence
By Jan Volavka. 397 pp. Washington, D.C., American Psychiatric Press, 1995. $54. ISBN: 0-88048-543-4

Volavka's introduction to violence began at the age of 10 in a Nazi prison: “I would not recommend such experience to future researchers into violence, but it certainly focussed my mind on the problem.” Perhaps for that reason, he makes short work of Nazi “theoreticians” and their Soviet and American counterparts, who would trace propensities for violence to the shape of a person's skull or the color of his or her skin. Since 1980 Volavka has written articles and book chapters on such diverse aspects of the issue as its neurobiology, epidemiology, clinical manifestations, and pharmacotherapy. In this, his first book, he pulls it all together in an up-to-date review (over 800 references) of a scientific literature ordinarily fragmented between disciplines.

This is a sensitive subject, to say the least. For example, when the head of the Alcohol, Drug Abuse, and Mental Health Administration casually suggested in 1992 that monkey models might prove useful in understanding inner-city violence, his departure was not long in coming. Undeterred, Volavka reviews the animal models of aggression. In the process, he provides a nosology of violence, including predatory violence, competitive violence, defensive violence, and irritable violence (i.e., being in a really bad mood). It is hardly likely that all types of violence are mediated by a single underlying mechanism, so there will probably never be a “grand unifying theory of aggression,” as the author puts it, just as there cannot be a grand unifying theory of birth defects.

Absent a grand unifying theory, it was Volavka's original intent to write a book centered on neurotransmitters, wherein disturbances in specific neurotransmitter systems lead to violent behavior and, in turn, pharmacologic intervention corrects the behavior by correcting the original disturbance — a kind of Inborn Errors of Metabolism of violence. He actually got as far as chapter 3 before realizing that such a book “was beyond the current state of knowledge.” By my guess, it will be at least 20 years before such a book can be written. Given his broad knowledge of the field, it surprises me that Volavka even considered it possible at this time.

The author sensibly scaled back his ambitions to present us with a Neurobiology of Violence that is, in effect, a snapshot of a field in progress. In the process, he has broadened the scope of the book. As it now stands, only the first third of the book concerns the neurobiology of violence itself (chapters 2, 3, and 4); the second third concerns congenital and environmental antecedents of violence (chapters 5, 6, 7, and 8), and the last third the clinical ability to predict violence and the pharmacotherapy of violence (chapters 9, 10, and 11).

Throughout, Volavka is careful to emphasize the complex interplay between biology and environment. For example, placebo-controlled studies have shown that alcohol consumption increases the probability of aggression, but only in settings in which physical aggression is at least tacitly encouraged. Work in animal models demonstrates that brain serotonin regulates violent behavior, such that decreased serotonergic activity leads to increases in violence, and vice versa. Oppressive environments cause long-lasting decreases in brain serotonergic activity, leading to long-term increases in violent behavior. Large-scale studies of adopted children have demonstrated that there is no gene for violence; propensities for violence are not inherited.

Finally, with respect to violence in America, what is the relative importance of biology and of environment? The author does not touch on this question, but I will. Homicide rates in the United States are 10 times higher than those in most other Western countries; they are also 10 times higher than those in most traditional African societies that have remained politically stable. If it is assumed that biologic factors in violence are evenly distributed across countries and societies, it follows that only 10 percent of U.S. homicides are attributable to biologic forces, the other 90 percent being environmental in origin. Neurobiology of Violence is a useful reference book for exploring further the scientific literature concerning the biologic side of the equation.

Brandon S. Centerwall, M.D., M.P.H.
University of Washington, Seattle, WA 98195