ADOLESCENT KILLERS EXHIBIT MARKED NEUROLOGICAL DEFICITS

A study of juveniles condemned to death reports compelling evidence that they exhibited serious neurological impairment at the time they committed their crimes.

Dorothy Otnow Lewis and colleagues evaluated 18 males who had received the death penalty in Texas. All had been 17 years old at the time they committed murder. At the time of the evaluations, the subjects were in their mid-20s. Each subject underwent neurological, neuropsychological, psychiatric, and educational evaluations.

The researchers report that:

• Three subjects had been born prematurely (one weighing only 3 pounds), a fourth was delivered by Cesarean section because the umbilical cord was wrapped around his neck, and the mother of a fifth had attempted to abort him. Overall, the researchers report, "six (33 percent) of the group began life with potentially compromised central nervous system functioning, and a seventh reportedly was the product of a difficult delivery."
• All but one of the subjects had a history of multiple head injuries, often resulting in loss of consciousness.
• Neurological evaluation revealed that five of 17 subjects (one did not undergo neurological testing) exhibited one abnormal finding on testing of prefrontal lobe functioning, three had two abnormal findings, two had three abnormal findings, and three had four or more abnormal findings. "It should be noted," the researchers say, "that most normal individuals have no signs of frontal lobe impairment on neurological examination." In addition, three subjects exhibited significantly impaired motor function.
• Neuropsychological testing revealed impairment on at least two traditional structured tests of "executive functions" (brain functions including planning and organization) in 10 of the subjects. On the unstructured Iowa Gambling Task, which also measures executive functions, 84 percent of subjects exhibited marked impairment. Overall, the researchers say, "every subject demonstrated signs of prefrontal cortical dysfunction on neurologic examination, neuropsychological testing, or both."
• Psychiatric evaluation revealed that eight subjects had histories and signs and symptoms consistent with early-onset bipolar spectrum disorder, while another four had histories and signs and symptoms consistent with early-onset schizoaffective disorder. Of the remaining six subjects, the researchers say, "three were clearly hypomanic" and one exhibited paranoia. Another subject apparently had committed his crime while sleepwalking, and his father had also exhibited parasomnia (unusual behavior during sleeping). Many subjects reported experiencing dissociative symptoms ("spacing out" or "out-of-body" episodes). Six had started abusing alcohol or drugs before their 13th birthdays.
• All but one of the subjects came from very violent or abusive families, "in which mental illness was prevalent in multiple generations."
• Only one subject was mentally retarded, with one other diagnosed as "borderline." However, six had lower reading scores than would be predicted by their IQ scores. The majority showed significant impairment in math, with 12 subjects exhibiting at least a 20-point discrepancy between overall IQ and mathematical reasoning ability scores. Eight subjects repeated grades in school, and the other 10 had been placed in special education classes or transferred to alternate schools. By second grade, more than one- third were having serious problems in school; by sixth grade, 78 percent had been identified as needing special assistance (primarily for emotional rather than intellectual reasons).

The researchers cite current evidence showing that the prefrontal cortex and temporal lobes (both critical to reasoning and self-control) do not mature until late adolescence. Teens with brain dysfunction and/or mental illness, they note, would be even more vulnerable to impairments in judgment and impulse control. Thus, they say, "Our data... raise a question of ethics: to what degree does it behoove our justice system to modify its criteria for mitigation and culpability and adopt rules consistent with the findings of early 21st century neuroscience?"

In earlier research involving adult murderers (see related article, Crime Times, 1995, Vol. 1, No. 4, Page 1), study coauthor Pamela Blake and colleagues reported that "specific neurologic diagnoses could be established in 20 of the 31 subjects."

"Ethics questions raised by the neuropsychiatric, neuropsychological, educational, developmental, and family characteristics of 18 juveniles awaiting execution in Texas," Dorothy Otnow Lewis, Catherine A. Yeager, Pamela Blake, Barbara Bard, and Maren Strenziok, Journal of the American Academy of Psychiatry and the Law, Vol. 32, 2004, 408-29. Address: Dorothy Otnow Lewis, 10 St. Ronan Terrace, New Haven, CT 06510, dorothy.lewis@yale.edu.

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