This article originally appeared in Medical Ethics, Vol. 10, Issue 3 (Fall 2003) and is reprinted with permission from the Lahey Clinic.

Traumatic Brain Injury and Criminal Responsibility

By William J. Winslade, PhD, JD Professor of Psychiatry and Behavioral Sciences, Institute for the Medical Humanities University of Texas Medical Branch, Galveston

Traumatic brain injury for decades has been, and continues to be, a major public health problem in the United States. Car crashes, gunshot wounds, falls and sports injuries account for two million brain injuries a year, nearly 400,000 hospital admissions, and at least 60,000 deaths. Approximately 90,000 people suffer a severe brain injury and survive but require extended, expensive rehabilitation. Some 2,000 people a year lapse into permanent unconsciousness lasting for months or years before they die.
Some survivors of traumatic brain injury fully recover, but many others experience a multitude of cognitive, emotional and behavioral disabilities. For example, attention deficit and memory loss may affect cognitive functioning. People with brain injuries often deny their disabilities; yet they are extremely frustrated by their inability to think clearly or perform tasks that came easily before their injury. Personality changes are common. Those who were calm and controlled may become quick-tempered and impulsive. In some people anger erupts into aggressive attacks on others. Many with severe brain injuries lack the ability to control their thoughts, emotions, impulses and their conduct. They may become uninhibited, promiscuous, anxious, paranoid or violent.1
People with severe brain injury may require close supervision in a controlled environment to prevent violent outbursts and other impulsive behavior. It is because such people lack the ability to control their impulses and conduct, that they may pose a threat to others and themselves. Although not all people with severe brain injury are dangerous, a history of traumatic brain injury is more common among prisoners than the general population.2 In two classic studies of 15 adults and 14 juveniles on death row in the mid-1980s, psychiatrist Dorothy Otnow Lewis found all 29 inmates had a history of traumatic brain injury. One might assume that their brain injuries would have been discovered and taken into consideration during their trials or at sentencing. Yet Lewis reported that evidence of brain injury was not uncovered at all, much less presented in the legal proceedings.3, 4
When I was invited in 2000-15 years after Lewis' studies were published-to speak to the National Public Defenders Association about traumatic brain injury and criminal responsibility, I discovered that only a few of the 800 public defenders were familiar with Lewis' research. This provoked me to explore further the relevance of brain injury to criminal responsibility. It also raises questions about the roles of psychiatrists, psychologists and other health care professionals in evaluating the impact of brain injury on behavior.
Criminal responsibility presumes that people have the capacity to control their conduct and to choose whether to commit crimes. Those whose mental capacity is severely impaired may be found not guilty by reason of insanity for an act they committed that would otherwise be a crime. Although disagreement exists about the tests for insanity, it is sometimes clear that traumatic brain injury can cause cognitive and behavioral changes in a person who meets the test for insanity.
One dramatic example is that of a 20-year-old man severely brain damaged from a near fatal car crash. Although before his accident he was a responsible, polite, nonviolent young adult, afterward he became increasingly suspicious and delusional. He formed an overwhelming paranoid delusion that his mother, with whom he had previously had a good relationship, had become part of a conspiracy to kill his father. One day he was at the drugstore with his mother when she was picking up some cardiac medication (coumadin) for his father. The pharmacist said to her jokingly, "What are you going to do with all this rat poison?" The young man's paranoid delusion about the conspiracy intensified and he felt compelled to kill his mother to protect his father. When he and his mother got home, he shot her to death. The psychiatrists who evaluated the young man all
agreed, as did the attorneys, that he was insane because they thought he was a paranoid schizophrenic. Although it was clear that he was legally insane, after he was committed to a mental institution, it was discovered he was not suffering from schizophrenia. Only later did his physicians realize that his traumatic brain injury rather than schizophrenia caused his paranoia.5
For purposes of criminal responsibility it is always relevant, as the Lewis research demonstrates, to evaluate psychiatric, neurological and neuropsychological factors that may have influenced the behavior of a person accused of a crime. When a person seems to have undergone a sudden personality change or acted wholly out of character in a strange manner, possible links to brain injury should be assessed. A history of traumatic brain injury may shed light on an accused person's conduct as well as their cognitive and emotional capacities. Although brain injury-even severe brain injury-may not provide sufficient evidence for insanity, it may help to explain criminal behavior, even if it does not excuse it. Evidence of brain injury may, however, be a factor that affects whether an alleged crime is classified as a serious felony or a lesser offense. If a person is convicted of a crime, evidence of brain injury may be considered as a mitigating factor with regard to severity of punishment. In view of the relevance of brain injury to criminal responsibility, attorneys have a responsibility to consider whether brain injury may have influenced a defendant's behavior. Appropriate health professionals, especially neuroscientists, neurologists and neuropsychologists, can conduct evaluations to diagnose brain injury. Recent refinements in neuroimaging techniques-such as CT scans, MRIs or PET scans-and psychological testing for impulse control disorders may help explain a defendant's behavior. As diagnostic techniques become more precise and our understanding of how brain injuries may influence behavior increases, the legal system should take new knowledge into consideration in assessing criminal responsibility. As health professionals, we must be cautious to avoid making premature claims about our knowledge of how brain function affects behavior. At the same time evidence of brain injury is relevant to judgments about the degree to which a behavior is subject to a person's control. Health professionals should present reliably obtained relevant evidence. Judges and juries must decide how much credibility and weight to assign to the evidence. We know enough already to know that our brains influence our behavior and that damaged brains impair control of behavior. The scientific community should give closer scrutiny to the connections between brain injury and behavior, not only to assist the legal system in assigning criminal responsibility, but also to help discover better ways to help persons with brain injuries to regain control of their impulses and their conduct.

1 Winslade WJ. Confronting Traumatic Brain Injury: Devastation, Hope and Healing, New Haven and London: Yale University Press, 1998.
2 Morrell RF, Merbitz CT, Jain S, Jain S. Traumatic brain injury in prisoners. Journal of Offender Rehabilitation 1998;27(3/4):1-8.
3 Lewis DO, Pincus JH, Feldman M, Jackson L, Bard B. Psychiatric, neurological, and psychoeducational characteristics of 15 death row inmates in the United States. AmJ Psychiatry 1986;143:838-45.
4 Lewis DO, Pincus JH, Bard B, Richardson E, Prichep LS, Feldman M, Yeager C. Neuropsychiatric, psychoeducational, and family characteristics of 14 juveniles condemned to death in the United States. Am J Psychiatry 1988;145:584-9.
5 Winslade WJ. Traumatic brain injury and legal responsibility. In Marcus SJ (ed). Neuroethics: Mapping the Field Conference Proceedings, May 13-14, 2002, San Francisco, California. Dana Press: New York, 2002;74-82. Available in PDF format at ( press/neuroethics/).