Brain Difference in Psychopaths Identified by DT-MRI Tractography

The study investigated the brain biology of psychopaths with convictions that included attempted murder, manslaughter, multiple rapes with strangulation, and false imprisonment. Using a powerful imaging technique, the researchers have highlighted biologic differences in the brain that may underpin these types of behavior and provide a more comprehensive understanding of criminal psychopathy.

The study was conducted by Prof. Declan Murphy and colleagues Dr. Michael Craig and Dr. Marco Catani from the Institute of Psychiatry at King's College London (UK). The results of their study were published in the June 9, 2009, issue of the journal Molecular Psychiatry. Dr. Michael Craig said, "If replicated by larger studies the significance of these findings cannot be underestimated. The suggestion of a clear structural deficit in the brains of psychopaths has profound implications for clinicians, research scientists and the criminal justice system.”

While psychopathy is strongly associated with serious criminal behavior (e.g., rape and murder) and repeat offending, the biologic basis of psychopathy remains poorly understood. Moreover, some investigators stress mostly social reasons to explain antisocial behaviors. To date, nobody has investigated the "connectivity” between the specific brain regions implicated in psychopathy.

Earlier studies had suggested that dysfunction of specific brain regions might underpin psychopathy. Such areas of the brain were identified as the amygdale, i.e., the area associated with emotions, fear, and aggression, and the orbitofrontal cortex (OFC), the region that handles with decision-making. There is a white matter tract that connects the amygdala and OFC, which is called the uncinate fasciculus (UF). However, no one had ever studied the UF in psychopaths. The investigators from King's used an imaging method called in vivo diffusion tensor magnetic resonance imaging (DT-MRI) tractography to analyze the UF in psychopaths.

The investigators found a significant reduction in the integrity of the small particles that make up the structure of the UF of psychopaths, compared to control groups of people with the same age and intelligence quotient (IQ). In addition, the level of abnormality was significantly related to the degree of psychopathy. These results suggest that psychopaths have biologic differences in the brain that may help to explain their offending behaviors.

Dr Craig added, "This study is part of an ongoing program of research into the biological basis of criminal psychopathy. It highlights that exciting developments in brain imaging such as DT-MRI now offer neuroscientists the potential to move towards a more coherent understanding of the possible brain networks that underlie psychopathy, and potentially towards treatments for this mental disorder.”

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Institute of Psychiatry at King's College London