A Research on Psychopathy as a Neuro-developmental Disorder

Psychopathy is a personality disorder characterized by a certain set of traits. It can be broken down to 16 key characteristics combined of behavioural, interpersonal and cognitive. A psychopath can be described as an individual who suffers from constant antisocial behaviour, lack of remorse, lack of empathy and damaged egotistical traits. Descriptions of psychopaths can vary slightly and exist in most cultures. Cleckley proposed that “psychopaths wear a superficial mask of intelligence and charm but are susceptible to impulses and show lack of remorse” (Cleckley, H. 1941). It is most commonly assessed with the Psychopathy checklist (PCL-R), based on the concepts of Cleckley and Joan McCord. A neurodevelopmental disorder can best be described as disturbed development of the central nervous system and abnormalities in the brain. This can then lead to neuropsychiatric problems, impaired motor function, difficulties in verbal and no verbal communication. Most origins often start at a young age during childhood and this then runs a stable course throughout the rest if that individual’s development, without much relapse or remission. This is then continued into adult life and can result in many impairments in occupation and academia. The main of this essay is to understand whether psychopathy is a neurodevelopmental disorder as the similarities between both seem to be significant.

One of the main areas which is still actively being explored are abnormalities and damages within the brain and neural system. Abnormalities with the amygdala and the prefrontal cortex has been heavily associated with impairments relating to social skills and learning – areas connected to psychopathic behaviour. when looking at individuals who have suffered traumatic brain injuries in these regions, they tend to lack moral reasoning and the ability to behave correctly in society. One of the earliest cases of this condition is that of Phineas Gage (Harlow JM 1941). In this case the damage done to the frontal lobe region had resulted in psychopathic like features such as lack of empathy, erratic behaviour and the inability to control emotion. The same can be seen when looking at neurodegenerative diseases which attach parts of the brain. Patients often suffer from bursts of violent episodes and empathy. We can see evidence of this from MRI studies with abnormalities within the brain of psychopathic individuals that control areas such as impulsivity, emotion and morality. A 2010 meta-analysis found that psychopathic individuals had damaged structure in the prefrontal cortex and orbitofrontal cortex. When looking at PCL-R scores between those who have neural impairments compared to those who do not; a notable difference is seen in the amygdala, hippocampus and temporal cortex (Weber, Sabrina, 2008). This suggests that these internal abnormalities are key in processes such as learning and social development and having any sort of damage or abnormality will greatly affect the individual. Previous research further illustrates this point as individuals who score higher than 25 on the PCL-R and who have a history of violence have reduced white matter which connects the amygdala and orbitofrontal cortex. This may explain offending behaviour, as the amount of abnormality directly correlates to the extent of an individual’s psychopathic tendencies. The reduction of matter can also be seen in a study conducted by Raine et al which also showed reduced grey matter volumes with individuals with ASPD scored highly on psychopathy (Raine A, Lencz T, 2000). On the other hand, there have been studies where people who have scored highly on factors relating to cunning and manipulativeness actually have increased white matter, but still decreased grey matter. The increase in white matter suggests increased ability of processing information which can enable an individual’s ability to lie quicker in situations. A recent moral decision-making study where psychopathic people were asked to make decisions of a highly emotional nature shows the effects of the amygdala levels. The results showed that participants who scored high on the interpersonal factor had reduced functioning in the amygdala, which is thought to be key in decision making and behaving in a moral manner. This gives a key insight into a psychopath’s decision-making process as they are able to seamlessly lie in situations, but still lack the morality needed from them in society.

When looking at neuroimaging studies the link between psychopathy and neurodevelopment is more compelling. There have been numerous studies conducted where patterns in the temporal lobe are examined in response to emotional words. Two groups are compared; one made up of criminals and the other of volunteers. The results indicated that abnormalities in the amygdala results in low levels of fear and cognitive learning – traits similar to those with psychopathy. This is further seen in other similar studies conducted on criminals and control groups. The results conclude that reduced grey matter reduction on the prefrontal cortex contribute to poor decision making, impaired judgement and lack of emotion. The low levels of fear are also similar to that of one of the sub groups in the triarchic model - boldness. This factor is argued to be associated with reduced activity in the amygdala when presented with fearful stimuli. Further evidence that psychopathy is a neurodevelopmental disorder can be seen with psychophysiological studies. This type of study mainly focuses on the nervous system function and the reaction to neutral or emotional stimuli. Electrodermal activity is measured as it reflects sensations such as arousal and responsivity. When looking at these types of studies that focus on the sympathetic and parasympathetic nervous system, the general conclusion to be drawn is; that psychopathic individuals compared to non-psychopathic individuals seem to be less responsive to aversive stimuli (Arnett PA.1997). The limitations of this type of research is that the same responses have been identified in individuals with psychopathic like disorders, such as those with conduct disorder.

External factors starting from a young age can be seen as the leading factor is the onset of psychopathy and this hypothesis can combat the notion that psychopathy is purely a neurodevelopmental disorder. A PCL:SV study with a group of males from the ages of 8 to 48 studied which factors scored ten or more. The results of the study concluded that factors such as low income, neglect and a absent father scored strongly. Other significant factors also included depressed family members, harsh discipline and poor housing suggested the onset of psychopathy (Hare, Robert D. 1999). However more research is needed, and the overarching view is that psychopathy is hereditary and internal factors are more compelling compared to external factors.

Although this type of research is compelling, the overall literature is still largely unclear and needs more exploration. General trends of reduced activity in the brain during MRI, PET and fMRI studies are common with individuals with psychopathy. The research across all studies has shown that abnormal (smaller) amygdala size equates to lower emotional activity, which as a result offers a likely explanation as to why psychopaths have low empathy levels. This trend can further be seen in studies with children and young adolescents. These emotional and moral impairments at a young age may result in the young individual never fully developing their sense of reasoning and instead become characterized by aggression and violence. The findings also suggest that no one single region of the brain will result in an individual to psychopathy and people who incur neurological damage are likely to suffer psychopathic like characteristics.

It is fair to say that psychopathy may have a neurodevelopmental basis and future research with genetic studies, combined with longitudinal imaging studies are needed to further substantiate this neurodevelopmental hypothesis. This is largely being due to the fact that neurodevelopmental disorders are viewed to have a significant genetic basis. There has been evidence from behavioural genetic studies which have indicated an influence of genes on psychopathy. Although conducting these types of studies poses difficulties, examining the development of the neurobiological measures for psychopathic traits from an early age is crucial to furthering our knowledge. The results can be used to help with prevention and management of psychopathy through child, adolescent and even adulthood. For the time being there are several areas of previous research that need more exploration; the main being if that brain deficits actually result to the development of psychopathy, or whether an individual’s lifestyle lead to brain dysfunction in the first place.

References

1. Arnett PA. Autonomic responsivity in psychopaths: a critical review and theoretical proposal. Clin Psychol Rev. (1997); 903–936.
2. Board, Belinda Jane; Fritzon, Katarina. 'Disordered personalities at work'. Psychology, Crime & Law. (2005); 17–32.
3. Cleckley, H. The mask of sanity. 1st ed. St Louis (MI): CV Mosby; (1941).
4. Craig, M C; Catani, M; Deeley, Q; Latham, R; Daly, E; Kanaan, R; Picchioni, M; McGuire, P K; Fahy, T; Murphy, D G M. 'Altered connections on the road to psychopathy'. Molecular Psychiatry. (2009); 946–53.
5. Dawel, Amy; O'Kearney, Richard; McKone, Elinor; Palermo, Romina. 'Not just fear and sadness: meta-analytic evidence of pervasive emotion recognition deficits for facial and vocal expressions in psychopathy'. Neuroscience and Biobehavioral Reviews. (2012): 2288–2304
6. Glenn AL, Raine A, Schug RA. The neural correlates of moral decision-making in psychopathy. Mol Psychiatry. (2009);5–6.
7. Hare, Robert D. (1999). Without Conscience: The Disturbing World of the Psychopaths Among Us. New York: Guilford Press.
8. Harlow JM. Passage of an iron bar through the head. Boston Med Surg J. (1848); 389–393.
9. Pridmore, Saxby; Chambers, Amber; McArthur, Milford. 'Neuroimaging in psychopathy'. Australian and New Zealand Journal of Psychiatry. (2005); 856–65.
10. Raine A, Lencz T, Bihrle S, et al. Reduced prefrontal grey matter volume and reduced autonomic activity in antisocial personality disorder. Arch Gen Psychiatry. (2000); 119–127.
11. Weber, Sabrina; Habel, Ute; Amunts, Katrin; Schneider, Frank. 'Structural brain abnormalities in psychopaths—a review'. Behavioral Sciences & the Law. (2008); 7–28.
12. Yang, Y.; Raine, A. (2009). 'Prefrontal Structural and Functional Brain Imaging findings in Antisocial, Violent, and Psychopathic Individuals: A Meta-Analysis'.
13. Yang Y, Raine A, Lencz T, et al. Volume reduction in prefrontal grey matter in unsuccessful criminal psychopaths. Biol Psychiatry. 2005; 1103–1108.