Vol. 5, No. 3, 1999 Page 4

Signs of neurological dysfunction highest in repeat,
violent offenders, study shows

A large percentage of criminal offenders show signs of possible neurological dysfunction, "with the highest percentage being found among repeat violent offenders," according to a recent study by Matthew Robinson and Tom Kelley.

The researchers asked probation officers to randomly select several cases each, and grouped the selected offenders into three categories: 19 repeat violent offenders, 19 repeat nonviolent offenders, and 18 first-time offenders. The average age of the offenders was similar in all categories. Each probation officer was asked to assess the cases using the Kelley Form, designed by one of the authors for use in detecting warning signs of neurological dysfunction. In making their evaluations, the probation officers screened all medical and legal documents accessible to them, and interviewed the offenders when possible.

Robinson and Kelley say that an overwhelming percentage of offenders in all groups were substance abusers and exhibited psychological abnormalities (e.g., learning disabilities, attention deficits, memory problems, or behavior problems such as aggression or insensitivity). Other signs and symptoms of neurological dysfunction included:

In addition, they say, 42% of repeat violent offenders showed evidence of exposure to environmental toxins such as lead.

"With few exceptions," the researchers say, "[our data demonstrate] that a higher percentage of repeat violent offenders were characterized by cues of neurological brain dysfunction than repeat nonviolent offenders and first-time offenders." The factors that most differentiated repeat violent offenders from the other two groups, they say, were birth complications, family abuse, head injury, parental drug use, abnormal interpersonal characteristics such as aggression or lack of empathy, and substance abuse.

"Also," they say, "both repeat violent and repeat nonviolent offenders can be differentiated from first-time offenders in terms of maternal drug use during pregnancy," with 26% of repeat offenders but only 5% of first time offenders having been exposed to drugs before birth. "This would suggest," they say, "that among our sample of offenders, maternal drug use during pregnancy would appear to be a risk factor for repeat involvement in criminal activity, both violent and nonviolent in nature."

In addition to finding that violent repeat offenders are more likely to suffer from neurological dysfunction than nonviolent or first-time offenders, the researchers found that the violent, chronic criminals showed higher levels of dysfunction, averaging significantly more symptoms per offender than did the other groups.

The researchers note that all of the probation officers commented on the lack of medical data available to them in making assessments of offenders' neurological status, and they speculate that even higher levels of dysfunction probably existed among the population they studied. Yet even given the paucity of data available, they note, the number of offenders exhibiting evidence of probable neurological dysfunction was extremely high.

Even more importantly, Robinson and Kelley say, the study revealed that a high percentage of the offenders they studied suffered at very early ages from correctable conditions including toxic exposure, birth complications, poor diet, and medical problems. "Any and all of these potential sources of neurological brain dysfunction can be reduced or even eliminated," they say, "suggesting that repeat offending and violent repeat offending behaviors which relate to these conditions may also be reduced or prevented."


"The use of neurological cues by probation officers to assess brain dysfunction in offenders," Matthew Robinson and Tom Kelley, presentation to the Annual Meeting of the Academy of Criminal Justice Sciences, March 1998. Address: Matthew Robinson, Appalachian State University, Dept. of Political Science and Criminal Justice, Boone, NC 28608. Conference paper posted online at: http://www.acs.appstate.edu/dept/ps-cj/neurology.htm.

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