1. ¹Section of Brain Maturation, Institute of Psychiatry, De Crespigny Park, London, UK
2. ²Natbrainlab, Institute of Psychiatry, De Crespigny Park, London, UK
3. ³Section of Neuroimaging, Institute of Psychiatry, De Crespigny Park, London, UK
4. ⁴Department of Forensic Mental Health Science, Institute of Psychiatry, De Crespigny Park, London, UK

Correspondence: Dr MC Craig, Psychological Medicine, Institute of Psychiatry, PO50, 16 De Crespigny Park, Denmark Hill, London SE5 8AF, UK. E-mail: m.craig@iop.kcl.ac.uk

Received 7 August 2008; Revised 25 February 2009; Accepted 13 April 2009; Published online 9 June 2009.

Abstract

Psychopathy is strongly associated with serious criminal behaviour (for example, rape and murder) and recidivism. However, the biological basis of psychopathy remains poorly understood. Earlier studies suggested that dysfunction of the amygdala and/or orbitofrontal cortex (OFC) may underpin psychopathy. Nobody, however, has ever studied the white matter connections (such as the uncinate fasciculus (UF)) linking these structures in psychopaths. Therefore, we used in vivo diffusion tensor magnetic resonance imaging (DT-MRI) tractography to analyse the microstructural integrity of the UF in psychopaths (defined by a Psychopathy Checklist Revised (PCL-R) score of 25) with convictions that included attempted murder, manslaughter, multiple rape with strangulation and false imprisonment. We report significantly reduced fractional anisotropy (FA) (P<0.003), an indirect measure of microstructural integrity, in the UF of psychopaths compared with age- and IQ-matched controls. We also found, within psychopaths, a correlation between measures of antisocial behaviour and anatomical differences in the UF. To confirm that these findings were specific to the limbic amygdala–OFC network, we also studied two 'non-limbic' control tracts connecting the posterior visual and auditory areas to the amygdala and the OFC, and found no significant between-group differences. Lastly, to determine that our findings in UF could not be totally explained by non-specific confounds, we carried out a post hoc comparison with a psychiatric control group with a past history of drug abuse and institutionalization. Our findings remained significant. Taken together, these results suggest that abnormalities in a specific amygdala–OFC limbic network underpin the neurobiological basis of psychopathy.