
Psychiatric News June 17, 2005
Volume 40 Number 12
© 2005 American Psychiatric Association
p. 22
Clues to Criminal Mind Found in Prefontal Cortex
Joan Arehart-Treichel
A relatively intact prefrontal cortex may provide psychopaths with the
cognitive resources to manipulate and con others successfully and the
wherewithal to avoid detection and capture.
Not all criminal brains are created equal, a new study suggests. The study,
published in the May 15 Biological Psychiatry, was conducted by
Adrian Raine, Ph.D., a professor of psychology at the University of Southern
California, and colleagues. Raine is an international authority on the
psychophysiology of criminals.
During the past few years, evidence has been building that the prefrontal
cortexa region involved in judgment, planning, and decision
makingis often not the same in criminals and potential criminals as in
the general population.
In 2000, for example, Raine and coworkers reported that the prefrontal
cortex of violent, antisocial men was smaller than that of controls
(Psychiatric News, March 3, 2000). In 2002, two University of
Connecticut scientists reported that brain-wave responses to a memory task
were less potent in the prefrontal cortex of teens with conduct disorder than
in the prefrontal cortex of teens without the disorder (Psychiatric
News, April 5, 2002).
But how might the prefrontal cortex of successful criminals (those who
avoid capture) compare with that of unsuccessful criminals (those who get
caught)?
Raine and his team used five temporary employment agencies in Los Angeles
to recruit volunteers for their study. They gave the volunteers various tests
including the Psychopathy ChecklistRevised, Structured Clinical
Interview for the DSM-IV Mental Disorders (SCID I), and SCID Axis II
Personality Disorders (SCID II) to determine whether they had psychopathic
characteristics and, if so, to what degree. The researchers also determined
whether subjects had committed any crimes by examining state court records and
by asking subjects directly whether they had committed any offenses. To
minimize the chance that subjects would not admit to having committed crimes,
the investigators assured them that any admission they made would be
confidential. The scientists were able to do so because they had obtained a
certificate of confidentiality from the secretary of Health and Human
Services.
The researchers used the test results and crime information to compose a
study sample of 52 subjects13 with high psychopathy scores who had
escaped detection for their crimes, 16 with high psychopathy scores who had
been detected and convicted for their criminal acts, and 23 control
subjects.
The scientists then used structural magnetic resonance imaging (MRI) to
determine the volume of prefrontal gray matter in each of the subjects. They
found that the volume of prefrontal gray matter in the unsuccessful
psychopaths was 22 percent smaller than in the control subjectsa highly
significant difference. The volume of prefrontal gray matter was a little
smaller in the successful psychopaths than in the control subjects, but the
difference was not significant.
These results remained the same even when possibly confounding factors such
as age, socioeconomic status, substance abuse, or a history of head injury
were taken into consideration.
Although Raine and his team are not sure how to interpret these findings,
they propose a possible explanation in their study report: "In contrast
to unsuccessful psychopaths, successful psychopaths show a relative sparing of
prefrontal gray matter. Relatively intact prefrontal structure may provide
successful psychopaths with both the cognitive resources to successfully
manipulate and con others as well as sufficiently good decision-making skills
in risky situations to avoid legal detection and capture.
"In contrast, prefrontal structural deficits may render unsuccessful
psychopaths particularly susceptible to poor decision making; interpersonally
inappropriate, impulsive, disinhibited, unregulated, reward-driven antisocial
behavior; and reduced sensitivity to environmental cues signaling danger and
capture."
The study was funded by the National Institute of Mental Health and the
Wacker Foundation.
An abstract of "Volume Reduction in Prefrontal Gray Matter in
Unsuccessful Criminal Psychopaths" is posted online at
<www.journals.elsevierhealth.com/periodicals/bps/article/PIIS0006322305000983/abstract>.
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