BOSTON – A traumatic injury to the brain can cause even the most mild-mannered person to act like a hostile, aggressive sociopath, a neuropsychiatrist said at the annual meeting of the American Academy of Psychiatry and the Law.
Agitation and aggression, often lumped together as "socially inappropriate behavior," are common after a traumatic brain injury (TBI), said Dr. Hal S. Wortzel, director of neuropsychiatric consultation services at the Denver VA Medical Center.
Dr. Hal S. Wortzel
But a TBI does not pre-ordain violent or aggressive behavior, and there might be other explanations for antisocial actions, Dr. Wortzel commented.
"Sometimes as clinicians, it’s sufficient to say that aggression in general might be related to this traumatic brain injury," he said. "But as forensic evaluators, we’re often times asked to comment on a specific act of aggression. We have to think about the typologies of violence, because not all aggressive acts are the same," he said.
The link between TBI and aggression has been well known since the famous case of Phineas Gage, Dr. Wortzel noted. Gage was a Vermont railroad worker who in 1848 survived, and, remarkably, recovered rapidly from an accident in which a heavy iron tamping rod more than 3 feet in length was driven by an explosion completely through his skull. After the accident, Gage underwent a dramatic personality change, and began to display irreverent and antisocial behavior, use of sexually explicit language, apparent lack of moral conscience, impulsiveness, irritability and aggressiveness, and an inability to focus on work or plan for the future.
Posttraumatic aggression is a common problem after TBI, usually manifesting within the first year post-injury. It has been associated with frontal lobe lesions and with the presence of major depression. In addition, it is more often occurs in patients who prior to their injury had a history of substance abuse or impulsive aggression.
The severity of a TBI is graded from mild to severe, according to the physical, neurologic, and psychiatric findings at the time of the injury, and not by the subsequent neuropsychiatric changes, Dr. Wortzel emphasized.
"Mild traumatic injuries are different from moderate and severe traumatic brain injuries in terms of outcomes, expected recovery, and the likelihood that neuropsychiatric symptoms, whether [they] be aggression or others down the road, are directly referable to neuronal injury from that event," he said.
Neurobehavioral outcomes after a TBI arise from a combination of pre-injury factors, the nature of the injury itself, and post-injury psychosocial factors. Changes might be come in the domains of cognition (such as disturbed consciousness or impaired attention), emotion (depression, anxiety, lability), behavior (aggression, disinhibition, apathy), and physical (visual problems, vertigo, seizures).
Pre-injury factors contributing to acquired aggression include age and gender, baseline intellectual function, psychiatric problems and substance abuse, sociopathy, risk-taking/novelty seeking behaviors, premorbid behavioral problems, social circumstance, and neurogenetic factors, such as the apolipoprotein E4 allele.
Factors that might exacerbate neuropsychiatric problems after an injury include medical complications, delay in receiving rehabilitative services, lack of education about the course of recovery and interpretation of symptoms, poor family or social support, premature return to work or school, and litigation or other legal problems.
"Sometimes as clinicians, it’s sufficient to say that aggression in general might be related to this traumatic brain injury."
Most people who sustain a mild TBI will recover fully and fairly quickly, Dr. Wortzel said. However, anywhere from 35% to 60% of people who sustain moderate to severe TBI develop chronic neurobehavioral and/or physical symptoms related to the injury, and the more severe the initial injury, the lower the chance of full neurological, neurobehavioral, and functional recovery, Dr. Wortzel said.
He noted that the nature and quality of violent behavior, plus the circumstances under which it occurs, provide clues to whether the aggression might be related to TBI or to some other cause, such as intoxication, delirium, or premorbid antisocial traits.
In a study of 279 Vietnam War veterans with penetrating TBIs, Jordan Grafman, Ph.D., and his colleagues found that frontal ventromedial lesions were significantly associated with higher scores for aggression and violence, although the higher scores were generally associated more with verbal confrontations than with physical assaults (Neurology 1996;46:1231-8).
"It is worth keeping in mind that injury is not destiny, and that most people who sustain brain injuries don’t hurt other people," he said.
Dr. Wortzel’s work is supported in part by the Veterans Affairs’ Mental Illness Research, Education and Clinical Centers. He reported having no relevant financial disclosures.