Seminar: University Seminar on Cognitive and Behavioral Neuroscience (603)

Date: December 12, 2002

Title: The Neurological Contribution to Violence

Speaker: Jonathan Pincus, M.D., Washington VA Hospital

Attendees: Yaakov Stern, Co-Chair, Sergievsky Center, CPMC

Herb Terrace, Co-Chair, Psychology Department, Columbia University

Peter Balsam, Co-Chair, Psychology Department, Barnard College

Michael Goldberg, Neurobiology & Behavior Program, Columbia University

Janet Metcalfe, Psychology Department, Columbia University

Dustin Merritt, Psychology Department, Columbia University

Lance Kriegsfeld, Psychology Department, Columbia University

Ilia Karatsoreos, Psychology Department, Columbia University

N.J. Macintosh, Psychology Department, Yale University

Dani Brunner, PsychoGenics Company

Tammy Moscrip, Psychology Department, Columbia University

Jon Horvitz, Psychology Department, Columbia University

Jacqui Rick, Psychology Department, Columbia University

Kate Lynch, Psychology Department, Columbia University

Anja Soldan, Psychology Department, Columbia University

Nate Kornell, Psychology Department, Columbia University

Herman Buscke, Department of Neurology, Albert Einstein College of Medicine

Jackie Gottlieb, Neurobiology & Behavior, Columbia University

Robert L. Thompson, Psychology Department, Hunter College

Peter Schofield, Neuropsychiatry Department, Newcastle University

Rapporteur: Michael R. Drew

Summary:

Dr. Pincus began by remarking that the existence of neurology and psychiatry as two separate fields institutionalizes the mind/body distinction. The distinction, said Pincus, is false, as is the common belief that ethics and morals do not come from the brain. Pincus’ research is based on the supposition that ethics and morals do come from the brain. The brain’s role in these processes is illustrated by the famous story of Phineas Gage, a 19^th century railroad worker who sustained significant frontal lobe damage when a tamping rod shot through his head. Gage survived the injury without losing consciousness. Indeed, he walked himself a mile to the nearest tavern for medical treatment. Although the injury did not affect Gage’s cognitive ability – he could read, write, and perform arithmetic normally-- there were horrible changes in his behavior, characteristic of a loss of ethics, morals, and the sense of responsibility for his actions. Gage became a drinker, carouser, and fighter, ending up in ruin as a vagrant. His skull was put in the medical museum at Harvard because it was so shocking at the time that a lesion to the brain could affect ethics and morality without affecting other cognitive functions.

Pincus’ believes that the story of Phineas Gage provides a clue as to what makes people violent. Very few people are violent in adulthood: 70% of violent acts are committed by only 5% of the population. Most people don’t strike others in adulthood; adults may feel like it but they don’t do it. What controls this impulse? Pincus believes that some inhibitory process develops during childhood. Much aggression occurs in kindergarten, but the rate of violence declines sharply as children reach high-school age. The decline in violence occurs at a time when brain size is increasing significantly. The increase in brain size is due not to the creation of new neurons, but to the development of synapses and myelin. The myelination occurs primarily in the frontal lobe; the other lobes are myelinated much earlier in development. So the developmental decrease in violence may depend on normal development of the frontal lobe.

Pincus advanced the thesis that 3 elements combine and interact to produce violence. The first element, illustrated in the Phineas Gage story, is neurological damage that impedes ability to control aggressive impulses. Such damage can be temporary (e.g., drug-induced) or permanent. The second element is psychiatric illness. The illness need not fit into the neat categories used by psychiatrists. For example, paranoia itself is not a diagnosable psychiatric condition, but it is a real phenomenon that can cause one to misunderstand social situations and cause violence. But brain damage and mental illness alone do not make people violent.

The third factor is the experience of abuse in childhood. Abuse here is defined as treatment that leads to a legitimate and daily fear of injury or loss of life. Abuse alone does not lead to violence in adulthood: 80-90% of abused children do not commit abuse in adulthood.

These three elements interact to produce violence. Abuse provides a great deal of anger. When a history of abuse coexists with neurological damage or mental illness, there is a vulnerability to violence. Violence in this case refers to severe violence, including murder and sex crimes. The research leading to this model started with an idea from Dorothy Lewis, a friend and collaborator, who noticed that many violent juvenile offenders were prone to seizures. Pincus decided to look at the differences between violent and nonviolent juvenile offenders at a reform school. He initially doubted he would find an increased rate of brain abnormality in the violent. To his great surprise, however, all the violent offenders were neurologically impaired. Their disorders included dyslexia, epilepsy, and corticospinal abnormalities. In all, 2/3 of the violent offenders exhibited all three predisposing factors. By contrast, 50% of the nonviolent offenders had none of the factors, and overall there was a much lower rate of predisposing factors in the nonviolent. This finding was replicated at Bellevue Hospital in single blind study of violent and nonviolent juvenile inpatients. Pincus then undertook a longitudinal study of 32 children participating in the Police Athletic League in Hell’s Kitchen, New York. The violent and nonviolent groups were counterbalanced for sex, socioeconomic background, age and race. In the initial screening the 3 predisposing factors were significantly more prevalent in the violent. The children were assessed again 7 years later. Among those without the 3 predisposing factors in the initial screen, only 15% were violent during the intervening 7 years, but among those with all predisposing factors, 100% per violent. The violent offences included armed robbery, sexual assault, and homicide.

After these studies were published, the work received some media attention, and Pincus was asked by a defense lawyer to evaluate 15 death row inmates in Florida. All 15 inmates exhibited severe neurologic and psychiatric illness. Half had been in mental hospitals before committing the crimes for which they were being punished. All had been severely abused. Pincus then evaluated 14 of the 32 current (at the time) death row inmates who committed their crimes before the age of 18. All but one of the 14 had been abused severely. Two-thirds were brain damaged. Eighty percent were mentally ill. Two-thirds had been in a mental hospital before committing their crime.

Pincus then summarized the functional anatomy of the frontal cortex, with a view to elucidating its role in violence. The frontal cortex has 5 subdivisions. The precentral gyrus is the primary motor cortex, and it exhibits direct control over many motor functions. Just anterior to the precentral gyrus is a closely related area, supplementary motor area (SMA), which also controls movement. The areas anterior to the SMA are often called “prefrontal,” which Pincus believes to be a derogatory term assigned because neurologists under-appreciate the prefrontal cortex (PFC). Neurologists sometimes refer to the PFC as a “silent” area because damage to it does not affect performance on standard cognitive and neurosurgical exams. In fact, the PFC has many functions. The dorsolateral PFC controls executive functions, including goal-direction, judgment, planning, self-criticism, and social pragmatics. The cingulate gyrus, most of which is in the PFC, is associated with motivation, drive, and initiative. The orbitofrontal cortex is implicated in excitability, behavioral inhibition, judgment, and personality. The orbitofrontal area may play a role in inhibiting subcortical areas, such as the amygdala, that mediate anger and other emotions. Because its functions fall under the subjective rubrics of judgment and personality, orbitofrontal dysfunction is particularly difficult to identify in neuropsychological and neurological exams. Phineas Gage’s injury was to the orbitofrontal area.

Pincus has found that frontal dysfunction is prevalent in those predisposed to violence. Of 29 murderers he examined, all but 2 showed abnormal signs on neurological tests of frontal functioning. The signs included impaired visual tracking, impaired performance on the Luria tasks (movement sequencing and repetition tasks), and paratonia (inability to relax the extremities). For the remainder of the talk, Pincus described specific clinical cases.

The first case was that of a child molester. He showed a number of frontal neurological signs, as well as a severe magnetic gait symptomatic of Pick’s disease. The gait problems were ameliorated when cues were available to direct his movements. For instance, the patient had no difficulty climbing stairs, and placing footprint markers on the floor significantly improved his walking. The patient had normal cognitive functioning.

The second case was that of a woman who beat her husband. The violence began contemporaneously with a significant change in personality, including a drastic elevation in mood and expressiveness. The patient was euphoric and prone to wander the hospital interacting inappropriately with strangers. The patient performed normally on all neurologic exams, but a CT scan revealed a large tumor in the orbitofrontal cortex.

The third patient was a young man who tried to steal a truck in the middle of a crowded street. He was apprehended and sent to a mental institution. The patient exhibited choreic movements, and there was a family history of Huntington’s disease. The primary neuropathology in Huntington’s is a deterioration of basal ganglia pathways. The basal ganglia have prominent interconnections with frontal areas, raising the possibility the patient’s poor judgment and planning resulted from frontal dysfunction secondary to basal ganglia dysfunction.

The fourth case was that of a physician who underwent a drastic change in personality, marked by an increase in promiscuity and aggressiveness. He beat his wife, provoked fights, and touched his patients inappropriately. The physician was aware that his behavior was wrong and abnormal, but he felt powerless to stop it. The patient had severe difficulty with executive functions. He was unable to set up and sequence the supplies for starting an IV. He had severe difficulty altering ongoing behavior. The patient had three auto accidents, all due to his inability to change lanes in advance of the lane ending. In the neurological exam, the patient showed abnormal visual tracking and impairment on the Luria tasks. A CT scan revealed a very large lesion to the frontal lobe. The orbitofrontal cortex was completely obliterated.

The fifth patient was Joel Rifkin, a serial murderer who killed 17 people. Dr. Pincus evaluated Rifkin, and showed clips from a television newsmagazine that reported on the evaluation. Rifkin had normal cognitive functions and a superior IQ, but was impaired on the Luria tasks. A SPECT scan revealed some frontal abnormalities.

Discussion:

Dr. Goldberg: Is there a higher incidence of child abuse in violent delinquents versus nonviolent delinquents?

Dr. Pincus: Yes. Almost 100% of the violent offenders we’ve seen have experienced abuse.

Goldberg: If you look at violent and nonviolent prisoners with the same socioeconomic background, do you still see the correlation?

Pincus: It is hard to do that because many people who are incarcerated for nonviolent crimes are still violent. I would assume that most people who have all 3 predisposing factors are not violent. This is because most of the people who are violent and have these factors are not violent most of the time. For instance, Joel Rifkin killed 4 people per year; so most of the time he was not killing. This could be due to differences in opportunity. So it matters over what period of time you observe people.

Dr. Terrace: Does child abuse leave any signature in the brain?

Pincus: The trauma resulting from child abuse can. Shaking causes brain trauma. Abused children would be especially likely candidates for the 2^nd impact syndrome --a second concussion causes significantly more brain damage than does a first.

Terrace: What about abuse that is not obviously physical?

Pincus: The fear and the learning that results from abuse could cause structural changes in the brain. It could interfere with critical periods. The immature nervous system is very sensitive to deprivation and abnormal stimulus. As Hubel and Wiesel have shown, the brain cannot develop normally if it does not receive normal amounts and types of stimulation during certain early critical periods. I would imagine that there are psychosocial critical periods. Moreover, if there is some pre-existing neurological condition, that could cause abuse to be more severe.

Dr. Gottlieb: Could you discuss why violence is predominantly a male trait?

Pincus: Every group that is violent should be looked at using these same criteria. Depression is more common in women; violence is more common in men. Abuse tends to be more severe in boys. A big difference is that neurologic disorders are 5-7 times more common in males than females. Boys probably have delayed frontal myelination due to testosterone, and this may play a role in the violence. Within the family, however, 60% of violent acts are committed by women. So the setting is a moderating factor. Violence is one way for men to attain status, especially if they are no good at sports or academics. For women, violence is usually not an option, so they may instead turn to promiscuity.

Dr. Balsam: Could it be that violent kids are more likely to experience head trauma than are nonviolent kids, and this is responsible for the correlation?

Pincus: Violent kids are indeed more likely to experience head injury, so it could be that the violence is causing the head injury and not the other way around. But there are stories that lead you to the other conclusion. There was a guy who was abusing his stepdaughter sexually. Until the age of 15 he was sexually abused by his father and grandfather. For next 15 years he was normal. He had a steady job. He got married. But all that time he was fantasizing about having sex with a child. Then he got into a car accident and sustained a frontal injury. And after that he began sexually abusing his stepdaughter.

Dr. Macintosh: Have you studied any violent females?

Pincus: They have the same history. There was a girl in a halfway house who killed another girl with premeditation. The murderer experienced terrible abuse as a child. She showed abnormal neurological signs indicating frontal dysfunction. She showed symptoms of obsessive-compulsive disorder. She was depressed when she killed the other girl.

Dr. Gottlieb: You cast violence in very medical terms. But if you take a wider view of it, you see that violence is not limited to humans. It occurs in apes and other species as well. The violence that occurs in animals is of a different kind than that of which you have been speaking. Are you limiting yourself to a certain type of violence?

Pincus: I have not studied political violence. But I would guess that suicide bombers do have these predisposing factors. I bet they are depressed, neurologically damaged, and horrendously abused. Rape of boys is very common Arab societies. But I have not studied this; this is just my guess. In Nazi Germany there were up to 500,000 murderers. But that was only a small proportion of the population. There were 50 million people in the country, and 10 million men in the army. Maybe 5 million men had the opportunity to kill. But only 500,000 – that’s 10%-- of them chose to kill. What made them kill? What is different about those men? In Palestine there is a tremendous amount of social support for suicide bombers, but still the vast majority of Hamas members are not interested in becoming suicide bombers. I suspect there is something different about those who choose to become suicide bombers.