Literature Review on the Evolution of Psychopathy

Evolution of Psycopathy
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Evolution of Psychopathy
Abstract
Traditionally, traits such as selfishness, deceit, lack of empathy, egocentricity and manipulativeness used to play a crucial role in the conceptualization of psychopathy. In the past three decades, psychopathy has been redefined by the continuous violations of social norms such as stealing, inconsistent work behavior, lying and truancy. Due to this, psychopathy is considered as a personality disorder that is being characterized by strong antisocial traits. Its defining features are risk factors that influence violent behaviors. Researchers and neuroscientists have suggested that both orbitofrontal neuropsychological performance and genetic factors are developmental factors for psychopathy.
Introduction
Psychopathy is a personality disorder that is being characterized by behavioral, interpersonal and lifestyle traits such as lack of empathy and remorse, manipulation, glibness, grandiosity, shallow effect, irresponsible lifestyle and persistent violations of the social norms. The development and implementation of Hare’s psychopathy checklist-revised had improved the evaluation of this disorder. From PCL-R assessment, interpersonal and personality traits such as lying, lack of remorse and empathy, and manipulation are related to psychopathy. These traits are grouped in Factor 1 (F1). Antisocial traits such as impulsivity, irresponsibility and criminal behavior belong to Factor 2 (F2) (Hare, & Neumann, 2008).
Neuroscientists have established a connection between psychopathy and violent behaviors. They have suggested that the deficiency of violence inhibitors such as emotional ties, self-justifications, fear to punishments, and empathy facilitates the violent behaviors that are witnessed in psychopaths. Also, there is a proposition that psychopathy in adolescents may lead to the development of antisocial behaviors and violation of the law in adulthood.
However, there is a suggestion that the etiology of psychopathy contains an important biological component. This is due to recent studies that have demonstrated that genetic factors are contribute to the development of antisocial personality disorder (ASPD) that is linked to psychopathy. Genetic factors are believed to account for more than 50% of ASPD. Additionally, it has been demonstrated that some of the contributing factors for the development of psychopathy characteristics such cruelty, unemotional traits; detachment and manipulation in men are genetic factors (Furguson, 2010).
A reason why genes have been linked to psychopathy is the modulation of serotonin (5HT) on violent behaviors. This suggests that there is a relationship between serotonin and violent behaviors in which more violent individuals possess more psychopathic characteristics (Dolan, Anderson, & Deakin, 2001).
Monoamine oxidase A (MAOA) is one of the genes that have been linked to psychopathy. MAOA is an enzyme that catalyzes monoamines in the brain and is contains strands of 5HT. It is located in X chromosome (Xp 11.4-Xp 11.3) (Shih, Chen, & Ridd, 1999). The polymorphism repetitions (MAOA-uVNTR) have been described. MAOA-uVNTR is a repetition of more than 30 base sequences in the promoter region that affects the transcription in vitro. Carriers of 3.5-4 repetitions (alleles MAOAH) has higher expressions of the enzymes while lower expressions are present in carriers 2, 3, 5 repetitions (alleles MAOAL) (Sabol, Hu, & Hamer, 1998).
Molecular studies follow the same suggestion of linking ASPD and psychopathy, especially MAOAL allele is related to certain traits of psychopathy such as ASPD, impulsivity, and violence. In their study, Fowler and his colleagues established that MAOAL allele and psychopathy traits are associated.
A recent study by Romero-Rebollar et al. (2015), reveal that MAOA is linked with psychopathy. The study also demonstrates psychopathy and violence are strongly related. In the study, MAOL carriers demonstrated a strong relationship between low orbitofrontal performance and high factor 2 scores. The authors also propose that the low activity allele is a related to an increase in violent traits such as instrumental use and impulsivity. This is supported by the findings from fMRI’s studies that the development of these characteristics can be due to the tendency of individual experiencing negative emotions as MAOL carriers exhibit hyperactivity in emotion-related brain structures to negative emotional functions. Consequently, at behavioral level, MAOAL carriers exhibit an increase in personal distress and impulsivity.
Consequently, other structural MRI studies demonstrate that normal MAOL carriers demonstrate differences in the concentration of gray matter on the orbitofrontal area of frontal-inferior gyrus. In consideration of this functional and structural evidence, it is likely that MAOAL carriers will fail to process some cues that may inhibit them from violent behaviors and experience negative emotions.
Neurological Bases
Prefrontal Cortex
The first cases to suggest that damage to a specific area of the brain can cause personality changes was that of Phineas Gage who suffered a head wound that damaged his prefrontal cortex (Macmillan, 2000). The prefrontal cortex is related to the working memory and is important in attention and behavioral inhibition (Miller et al., 2002). Gage is believed to have survived the trauma but he demonstrated certain behavioral and personality trait changes such irresponsibility, verbal abusiveness, and became sexually promiscuous (Macmillan, 2000). These behaviors are associated with psychopathy. Based on Gage’s case, Macmillan argues that “the case took on a life of its own, accruing novel additions to Gage’s story without factual basis,” concluding that the case provides more evidence than the scientific evidence.
Due to the behavioral overlap, impulsivity being a psychopathy trait, and control of impulse is among the functions of the prefrontal cortex, it is likely that the damage of the prefrontal cortex is a cause of psychopathy.
Orbitofrontal Cortex (OFC)
Blumer and Benson’s study (1975; cited in Kiehl, 2006), demonstrated a condition referred to as “pseudopsychopathy" that is characterized by problems such as empathy, irresponsibility, reactive aggression, and impulsivity. All these are psychopathic traits but Hornak et al. (2003) suggest that there must be a bilateral OFC damage to cause these changes. Despite the damage of OFC accounting for some of the traits related to psychopathy, it does not affect an individual’s use of instrumental violence which is one of the major characteristics of psychopathy (Vien & Beech, 2006). Additionally individuals with OFC damage do not exhibit cruelty which is observed in most victims. OFC damage affects factors that are related to factor 1 and 2 of the 4 factor model.
Ventral Striatum
Carre et al. (2013) explored the role played by reactivity in the ventral striatum of psychopaths during a card-guessing game. The ventral striatum plays a crucial role is forecasting and informing rewards, and it is indicated in the “processing the motivational salience of stimuli,” (Carre et al., 2013). Damage to the ventral striatum may lead to the gambling addictions exhibited by psychopaths. In Carre et al.’s study, a total of 200 participants who had a high score on SRP-SF test were given a card that faced down and were expected to guess whether or not the value was higher or lower than five as they underwent the fMRI scanning. They were promised a monetary reward if their guess was right.
The interpretation of Carre et al.’s findings suggests that an increasing risk-taking behavior in psychopaths may be related to ventral striatum’s hyperactivity. They conclude that a ventral striatum dysfunction coupled with amygdale dysfunction accounts for all the four factors of psychopathy.
Amygdala
Earlier studies on the bases of psychopathy, amygdala dysfunction have been the major suspect that causes psychopathy (Moll, de Oliveira-Souza, Bramati, &Grafman, 2002). The amygdala is responsible for controlling individual emotions and instrumental learning. While psychopathy individuals are believed to be emotionless, recent studies experiments in amygdala dysfunction in psychopaths demonstrated hyperactivity to angry faces which is a contributor to reactive aggression. Despite amygdala dysfunction being responsible for most of psychopathic factors, it does not account for the full spectrum such as drug addiction.
Other Bases
According to Vien and Beech (2006), anterior temporal epilepsy contains most of...