Psychopathy is a personality disorder typically defined by certain personality traits and behaviours such as lack of empathy and guilt, manipulation of others and severe antisocial or violent behaviour (Viding E, McCrory E, Seara-Cardoso A, 2014). It is a developmental disorder due to the fact that it can be recognised in both childhood and adulthood (Frick, O'Brien, Wootton, & McBurnett, 1994; Hare, 1980, 1991), and is suffered by approximately 0.75–1% of the population (Viding E, McCrory E, Seara-Cardoso A, 2014). In this essay I will discuss the factors that cause psychopathy; these factors have been debated over time – on one hand it is argued that genetic influences on a person are what determines the development of psychopathy, nevertheless on the other hand, it is argued that social or environmental factors are what determines the development of psychopathy (R.J.R. Blair K.S. Peschardt S. Budhani D.G.V. Mitchell D.S. Pine, 2006).
It is argued that there is a genetic cause for psychopathy, and in order to investigate this, many psychologists have used twin studies in their research. Blonigen et al used 626 pairs of 17-year-old male and female twins and assessed them using the Multidimensional Personality Questionnaire. They found significant genetic influence on the two psychopathic traits: ‘Fearless dominance’ and ‘Impulsive Antisociality’, as twins showed similarities in their traits (Blonigen, Hicks, Krueger, Patrick & Iacono, 2005). In addition, Viding et al studied just under 3,500 twin pairs in the Twins Early Development Study, rating their callous-unemotional traits and antisocial behaviour. They found that exhibiting high levels of callous-unemotional traits and antisocial behaviours is under strong genetic influence and is under no influence of shared environment (Viding E, Blair R.J, Moffitt T.E, Plomin R, 2005.). These twin studies are a very efficient way of testing genetics, as twins are either monozygotic – where they share 100% of the same DNA – or dizygotic – where they share 50% of the same DNA; this means that researchers can have greater genetic control in the experiment. In addition, the twins will also almost always be subject to very similar upbringings and experiences, and therefore the researcher can be more confident that the results are due to genetics. This evidence can show that psychopathy, or psychopathic traits, has some genetic basis, however it could simply be that genetics are probabilistic and not deterministic – they do not ensure one will develop psychopathy but increase the likelihood of it.
Furthermore, research carried out on psychopathy has found that there is a fundamental neural region that appears to be dysfunctional in psychopaths: the amygdala (Blair R.J.R, 2007). The amygdala is a complex structure in the brain that is linked to fear and emotion control (Pessoa L, 2010), and neuroimaging has found low activation in this area in those with psychopathic traits. In addition, in a study carried out by Yang et al, participants underwent amygdala volume analysis and measurement, and it was found that individuals with psychopathy had significant reductions in volume of their amygdala in comparison to the control groups (Yang Y, Raine A, Narr K.L, 2009). This evidence can explain why individuals with psychopathy show a lack of guilt and emotion, as their emotional processing is affected. Nevertheless, it is possible that this effect on the amygdala could be a result of social or environmental factors, and therefore further research could be required into the lives of the psychopathic individuals.
In addition, it has been found that those with psychopathic traits such as antisocial or aggressive behaviour have a dysfunction in the operation of their MAOA gene – Monoamine oxidase A. MAOA is an enzyme that is used for monitoring and controlling levels of neurotransmitters in the brain, breaking them down after a nerve impulse has been transmitted. For the people whose MAOA gene does not work correctly, levels of neurotransmitters in the brain will be affected. A study carried out by Brunner et al looked into low MAOA activity that has been shown to be associated with various forms of aggressive and antisocial behaviour. Brunner et al studied 28 members of a Dutch family who had been involved in impulsively aggressive and violent criminal behaviours including rape and assault; they found that all these men had abnormally low levels of MAOA in their brains (Brunner H.G, Nelen M, Breakefield X.O, Ropers H.H, 1993). This also shows that there is a strong genetic basis in the development of psychopathy, nevertheless again this malfunction of the MAOA gene could be due to social and/or environmental factors and therefore further research into the participant’s lives and backgrounds could be required to improve this research.
An alternative explanation for the causation of psychopathy is that it could be down to social or environmental factors. Many studies have correlated an upsurge of psychopathic characteristics to poor or inconsistent parenting (McDonald R, Dodson MC, Rosenfield D, Jouriles E.N, 2011), specifically “poor supervision”, “physical punishment”, and “poor parent-child communication” (Pardini D.A & Loeber R, 2008). A study was conducted by Muratori et al, focusing on the effects of positive and negative parenting practices on the levels of callous-unemotional traits on 126 Italian children. They were treated by a multi-modal approach including parent-training, and it was found that increased levels of positive parenting predicted a decrease in the levels of callous-unemotional traits in the children (Muratori P, Lochman JE, Lai E, Milone A, Nocentini A, Pisano S, Righini E, Masi G, 2016). Moreover, it has been found that parental warmth displayed to children can have an effect on their behaviour: Hawes et al found that low levels of warmth predict increases in child’s callous-unemotional behaviour (Hawes, D., Dadds, M., Frost, A., & Hasking, P, 2011). These findings could be extremely important for the prevention of the development of psychopathy, as parents can be advised about the way they raise their children and the issue may be preventable. Nevertheless, a concern with these studies is that they have short follow-up times of one to four years, meaning we do not have a full understanding of the extent of the effects on the participants; to improve this research longer follow-up periods may be required.
There is also considerable evidence of an association between physical and sexual abuse and increased risk of aggression and impulsivity – prominent psychopathic traits (Dodge, Pettit, Bates, & Valente, 1995; Farrington & Loeber, 2000; Widom, 1992). A study was carried out by Weiler and Widom where previously abused and neglected individuals were matched to a control group of non-abused or neglected individuals, and measures of psychopathy were assessed using Hare’s Psychopathy Checklist. It was found that the victims of childhood abuse and/or neglect had significantly higher scores on Hare’s Psychopathy Checklist than the control group, even when there had been controls put in place to match demographic characteristics and criminal past in both groups (Weiler B.L & Widom C.S, 1996). In support of this, another study was carried out by Lang and Klinteberg investigating possible implications of childhood neglect and/or abuse on development of adult psychopathy. They used participants who had suffered high and low victimisation of childhood neglect and/or abuse in their lives. The researchers found those who had been victims of abuse and/or neglect exerted significantly more violence and had higher “Adult Psychopathy Checklist” scores than those who had lower victimisation, who had ”’none to minor’ later indications of violence, and low PCL scores” (Lang S & Klinteberg A.F.B, 2002). This evidence indicates that environmental and social factors have a prominent effect on the development of psychopathy, nevertheless we cannot rule out the possibility that these individuals may be genetically predisposed to the development of psychopathy.
Overall, the evidence provided in this essay shows that psychopathy has a strong genetic basis, with evidence showing elements of the brain having been affected, such as the amygdala and the MAOA gene, and twin studies showing twins sharing psychopathic traits. Nevertheless, the complex nature of psychopathy means it cannot be solely explained by genetics, as social and environmental factors also play a role in the development of psychopathy. Elements of people’s lives such as parenting and abuse or neglect are also shown to have an impact on the development of psychopathy in people. Therefore, the evidence indicates that both biological and social/environmental factors play a large role in causing the development of psychopathy in people.