The Neuroanatomy of Psychopathy

Dr Cesare Lombroso

Lombroso believed that 40% of criminals were ‘born criminals’ who could be distinguished by physical features including relatively long arms, prehensile feet with mobile big toes, low and narrow forehead, large ears, thick skull, large jaw, etc. The main objection to his hypotheses were his campaign on the basis of his theory for a preventive criminology: ‘society need not wait for the act itself, for physical and social stigmata define the potential criminal. He can be identified, watched and whisked away at the first manifestation of his irrevocable nature’.

As than as well as now the findings in the field of neuroscience of psychopathy does not legitimize the preventive incarceration of a ‘high-risk’ individual. Nor does it approve a therapeutically nihilistic approach to such an individual on the grounds that he is ‘beyond rehabilitation’.

What is psychopathy?
Psychopathy is a disorder, defined by Hare’s Psychopathy Checklist — Revised (PCL—R) and characterized in part by a diminished capacity for remorse and poor behavioral controls. Psychopathy is defined not only by antisocial behavior but also by emotional impairment such as the lack of guilt. The emotional impairment found in individuals with psychopathy interferes with socialization such that the individual does not learn to avoid antisocial behavior.

Psychopathy is not an official psychiatric DSM diagnosis. In the DSM it’s replaced by antisocial personality disorder. Only one third of those who are diagnosed with antisocial personality disorder meet criteria for psychopathy. Antisocial behavior shown by individuals with psychopathy is that it is mostly instrumental in nature, i.e. goal-directed towards achieving money, sexual opportunities or increased status. In British psychiatry psychopathy is still in use and studied. Most authors say that a diagnosis of psychopathy, unlike antisocial personality disorder, is informative regarding a patient’s future risk.

For a more extensive description of psychopathy have a look at article in Wikipedia

High level of psychopathy is associated with reduced amygdaloid volume and amygdala dysfunction. The amygdala is involved in emotions. It’s needed to recognize fearful and sad faces, it’s the “fear center”. The amygdala plays a primary role in the processing and memory of emotional reactions. Fear as well as learning from punishment is lacking in psychopathy. Amygdala dysfunction is believed to be one of the core neural systems implicated in the pathology of psychopathy.

Other scientists believe the main neural system associated with psychopathy is the orbitofrontal cortex and other regions of the prefrontal cortex. These brain structures are essential for learning from experience such as learning from punishment.

The more likely and more recent hypothesis suggested instead that the social and emotional deficits of psychopaths may reflect an interaction between orbitifrontal cortex and amygdala dysfunction.

In a recent publication in Molecular Psychiatry another area is added to this complex. The white matter that link the amygdala with the orbitofrontal cortex called the uncinate fasciculus is abnormal. For the location of the uncinate fasciculus see the picture below.

Unincate fasciculus

Interview with the researchers: Brain difference in psychopaths identified

In even a more recent publication the researchers of another group used a cortical pattern-matching method with MRI to investigate cortical gray matter thickness in psychopaths (n=27) and in non-psychopathic controls (n=32). Compared to non-psychopaths, the psychopaths had significant cortical gray matter thinning in the right frontal and temporal cortices.

The finding of right hemisphere pathology in psychopaths is consistent with observations from lesion studies, showing that damage to the right hemisphere impairs the ability for effective recognition, especially for negative facial expression, similar to dysfunctions documented in psychopaths

cortical thinning

It is unclear whether differences from control subjects in psychopaths are secondary or primary to the abnormalities in the amygdala and orbitofrontal cortex. Moreover, these are observational studies. It doesn’t give us a clue to what was first, nor does it exclude the consequences of the environment on the brain. We can’t distinguish cause and effect.

For a more in depth discussion about psychopathy and neurobiology please read: Psychopaths (sociopaths): White matter, unplugged
Benning, T. (2003). Neuroimaging psychopathy: lessons from Lombroso The British Journal of Psychiatry, 183 (6), 563-564 DOI: 10.1192/bjp.183.6.563
Blair, R. (2003). Neurobiological basis of psychopathy The British Journal of Psychiatry, 182 (1), 5-7 DOI: 10.1192/bjp.182.1.5
Craig, M., Catani, M., Deeley, Q., Latham, R., Daly, E., Kanaan, R., Picchioni, M., McGuire, P., Fahy, T., & Murphy, D. (2009). Altered connections on the road to psychopathy Molecular Psychiatry DOI: 10.1038/mp.2009.40
Yang, Y., Raine, A., Colletti, P., Toga, A., & Narr, K. (2009). Abnormal temporal and prefrontal cortical gray matter thinning in psychopaths Molecular Psychiatry, 14 (6), 561-562 DOI: 10.1038/mp.2009.12