Vol. 12, No. 2, 2006 Page 5
A recent study reveals a high percentage of brain abnormalities in sexual murderers, and suggests "the importance of a comprehensive neurological and psychological examination of this special offender group."
Peer Briken and colleagues evaluated psychiatric court reports of 166 men who committed sexual homicides between 1945 and 1991, and found that 31% of the men showed evidence of brain abnormalities. Abnormalities included epilepsy, traumatic brain injury, childhood encephalitis or meningitis causing brain damage, genetic disorders (including three cases of XYY), and unspecified brain damage. Sixty patients had undergone neuroimaging, and in 34% of these the results revealed pathology. A number of men had multiple signs of brain abnormalities, with 14 exhibiting two signs and six exhibiting three or more.
The sexual murderers with brain abnormalities had a history of more childhood behavior problems than the sexual murderers who did not exhibit brain abnormalities. They also had a higher rate of transvestic fetishism and paraphilias, and there was a trend for sexual sadism to be more frequent in this group. In addition, the subjects with brain abnormalities were significantly more likely to commit multiple murders. Conversely, the men with brain abnormalities were less likely to have alcohol problems or to have offended while under the influence of alcohol, which the researchers say "could indicate that these individuals need less disinhibiting factors to commit a homicide."
The researchers say, "Our findings of a substantial frequency of brain abnormalities and paraphilic psychopathology are… consistent with the hypothesis involving the importance of neurodevelopmental contributions in the genesis of serial sexual homicide."
"The influence of brain abnormalities on psychosocial development, criminal history and paraphilias in sexual murderers," Peer Briken, Niels Habermann, Wolfgang Berner, and Andreas Hill, Journal of Forensic Sciences, Vol. 50, No. 5, September 2005, 1-5. Address: Peer Briken, University Hospital Hamburg-Eppendorf, Martinistrasse 52, D-20246 Hamburg, Germany, briken@uke.uni-hamburg.de.