A Criticism on the Genetics of Psychopathy Essay

A Criticism on the Genetics of Psychopathy Essay

The 17th Century was still a time where the feudal class system was in power, especially in England. There still existed a rigid hereditary monarchy and aristocracy and the unquestioned power of the Church. However, the 17th Century also saw great changes in science as well as philosophy. Many ideas were brought up about the human mind and body – everyone sought a connection between the two aspects of human nature. John Locke an English philosopher was the first to talk about the notion of the ‘blank slate’ or tabular Rasa in Latin. Locke expresses the mind as a sheet of White paper’ to be filled up with the influences of experience’.
Despite Locker’s work, throughout the 17th to the 19th Century there existed a relatively fixed notion that human nature was dominant. That is, experience or one’s surroundings simply had nothing to do with it. The questionable pseudo sciences of phrenology and eugenics were parroted around and racial prejudice took a centre stage in many countries.A Criticism on the Genetics of Psychopathy Essay.  Significantly, the publication of Darning’s theory of evolution led some to believe that non-white races were the White Man’s Burden’ and thus placed a scientific badge to Justify imperialism and racial superiority.
The pseudo-science of eugenics coined by Darning’s own cousin, Francis Gallon advocated ‘selective breeding. This developed over a few decades into mass involuntary sterilizations of whole ethnic groups over a series of appalling world events that would permanently change intellectual thinking. World events such as the Holocaust – the murder of Jewish populations, Gypsies and homosexuals numbering in the millions; and persecution and segregation of African-Americans in American states solidified the doctrine of the blank slate as the modern perspective on theories of the mind (Pinker, 2004, p. 16).
In his book ‘The Blank Slate’, Steven Pinker follows the events in history which led to such differences in intellectual thinking then and today. This shift in thinking rejected the idea of human nature and racial superiority and saw the takeover’ of the doctrine of the Blank Slate; the belief that everyone despite ethnicity, gender or social background was born equal and shaped by their experiences. This revolution in intellectual thinking saw many countries begin to tackle internal problems to benefit the less fortunate groups. More attention was delegated to child development and social problems.
What is a Psychopath? A psychopath is an individual who is devoid of any empathy and moral compass. His/ her behavior will continually challenge the accepted behavior in society and the law. The psychopath’s inability to feel fear, guilt or empathy inhibits the individual to comprehend ethics and morality. As a result, the psychopath, without limitations and moral decency becomes a self-serving criminal. Psychopaths are known social predators and are adept at hiding what they are; blending seamlessly into communities. A Criticism on the Genetics of Psychopathy Essay. With no moral compass, they can lie, steal and kill without any remorse (Penn, 2013, p. 9). The Debate I will add a sense of structure to this debate by defining the opposing views. The many views that constitute this debate actually fall into a spectrum of opinions. There are the two extremist views situated at opposite ends of the spectrum and some that fall in between. Atone end is the view of ‘Biological Determinism’ and at the other is the ‘Doctrine of the Blank Slate’. Respectively, the term of ‘Naturists’ and ‘Nurtures’ are used to refer to individuals who take up either side of the debate. According to Jesse J. Print in ‘Beyond Human Nature’ and Steven Pinker in ‘The Blank
Slate’ the debate can be structured in this manner: The current situation of the debate remains at a position in which both sides have agreed that an individual’s traits and behaviors is an interaction between both genetic and environmental factors. The ideas promoted by the extreme ends of the spectrum have been abandoned and Nurtures now agree that a trait and/or behavior is determined by some (albeit little) genetic influence. It is evident that now the debate rests on the degree to which human nature or genes have a hold on who we become.
Biological Determinism believes that an individual’s traits and behavior is entirely encoded in heir genetic makeup. The Doctrine of the Blank Slate believes that an individual’s traits and behavior is entirely shaped by one’s surroundings. Thoroughgoing Nurturing Nurtures believe genetics plays a limited role in an individual’s development. We are almost entirely shaped by our experiences. It is not to be denied that we are born with a few innate ideas and our genes have some control over our lives but ultimately it is environmental influences that define us.
Main areas of environmental influences (Pinker, 2002, p. 56): Prenatal Environment (in utter) Education Domestic Life Peer Influence Culture Thoroughgoing Naturism This perspective follows the school of thought that an individual’s mind is born with innate ideas and moral compasses. Their traits and behavior is encoded in their genetic makeup and define who they are. Environmental influence can have some affect but these effects will be within the limitations set by a person’s genes.

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Epigenetic This is a relatively new branch of science that received little interest despite its discovery in the asses (most likely due to the excitement surrounding the human genome). The science of epigenetic challenges a whole host of ingrained notions about human DNA. It was originally believed that our lifestyles and choices would only affect our personal health in some way or the other. So when it was time to raise our kids, they would not and could not be affected; their genetic slate would be wiped clean’ (Cloud, 2010). A Criticism on the Genetics of Psychopathy Essay.
However, recent studies have shown substantial evidence that epigenetic is a force to contend with. Lifestyle choices such as smoking and overeating can leave a mark on the pigeon. If this is so, think of the potential lifestyle choices and powerful environmental conditions such as famine may have on the type of person our child grows up to be I. . Their personality, traits and behavior. This is highly relevant to the Nature-Nurture debate as it presents a fresh perception on the rather stagnant debate. What can epigenetic mean for the Naturists and Nurtures?
Well, it certainly threatens the nature debate as its implications means that our DNA can be changed by our environment. More importantly, what can epigenetic mean for psychopath? These questions will be answered further on. How can Genes and our Surroundings affect us? Consider the Nature-Nurture debate in a wider perspective: where it can affect every single one of us. It can be argued that a person’s destiny or self-identity is made up of their traits and behavior. We are who we are as a direct result of our personality and our actions.
Where we end up in life and the person we become is essentially determined by our traits and our behavior. There are a number of physical characteristics that are controlled by a small group of genes. These include sensory abilities such as color vision and blood group. These have less of an impact on our traits and behavior. For example, humans are able to see color due to the photosensitive cells in the retina called ‘cones’. There are 3 kinds of cones and each sensitive to short, medium and long lightfaces.
Light reflects off objects in different lengths of lightfaces and the color you see depends on the proportion of each length of lightface (Print, 2013, p. 23). There is a distinct biological link between color vision and genes that allow photosensitive cells to be produced. On the other hand, as we move into more complex psychological traits, we find that the link between genes and behavior becomes distorted. The reason for this is due to the fact that many psychological traits involving the human mind, is often controlled by ore than one gene. It is multimedia.
There can even be non-genetic factors at play I. E. Environmental factors affecting a psychological trait. The question of the moment regarding Nature and Nurture, is how much are genes contributing? The Nature- Nurture debate and Psychopath When we focus in onto the situation of psychopaths and their position in the Nature- Nurture debate, we see a whole lot of elements that we do not understand yet. I aim to shed some light and understanding on the debate and especially on psychopath and how they are linked to this debate. One of the critical questions in psychopath s What makes a psychopath?
Is it a matter of genetics that determines if a child will grow up to be psychopathic? Or is it an interaction of the environment that shapes a psychopath? In psychopathic individuals it forms a major problem when it comes to dealing with them because we do not understand them. Therefore, it becomes even harder to distinguish their position in society. Are they within medical help? In which case, as it is in many parts of the world, the psychopath is treated as an individual requiring medical treatment. Are they able to be re-introduced back into society and not pose a threat?
And if they are not, what is to become of the psychopath then? Ultimately, in most instances it has been shown that psychopaths are beyond medical help. A Criticism on the Genetics of Psychopathy Essay. Many clinically diagnosed psychopaths have shown almost no improvement after long periods of medical and psychiatric treatment. The only to do is diagnosis: the devised method for diagnosing psychopath is through observation of an individual’s behaviors. Robert Hare (2008, p. 23) developed the most commonly used guidelines for doing the Job called the ‘Psychopath Checklist-Revised’ or the PC-R. The following twenty traits are used: 1 .
Glibness and superficial charm 2. Grandiose self-worth 3. Pathological lying 4. Cunning/manipulative 5. Lack of remorse or guilt 6. Shallow affect / emotional poverty 7. Callous/lack of empathy 8. Fails to accept responsibility for own actions 9. Needs stimulation/prone to boredom Parasitic lifestyle 10. Poor behavioral controls 11. No realistic long-term goals 12. Impulsiveness 13. Irresponsible 14. Juvenile delinquency (between ages of 13-18) 15. Early behavior problems (before age 13) 16. 17. Revocation of Conditional Release (e. G. Violating probation) 18.
Promiscuity Many short-term marital relationships 19. Criminal versatility (variety of criminal offenses) 0. The ‘Psychopath Checklist-Revised’ shows the 20 most common traits compiled by Robert Hare over many years of observing known psychopaths in America’s prisons. The Nurture Debate The main areas of environmental influences can affect us in different ways. Additional elaboration has been given to each of these aspects explaining Just how they can affect our traits and behaviors. Prenatal Environment is sometimes termed ‘in utter’ which refers to the fetal surroundings inside the womb.
There has been substantial evidence demonstrating the effects of malnutrition prenatal as well as postnatal. These are long term consequences and are caused by inadequate caloric/ vitamin intake during fetal development. The effect of excessive fat, carbohydrate or protein intake can also have permanent consequences on the baby, resulting in the child being predisposed to cardiovascular disease, diabetes and cancer. (Misses-Alloy, G. , 2008) Education makes a fundamental difference in lives today. Armed with institutional qualifications, we gain better Job prospects and consequentially better financial prospects.
Consider poorer countries where an education is hard won and you can already envision a bleaker future. Furthermore, the influence of an optimal learning environment I. E. School can increase your ‘Q! IQ scores have been shown to increase by 2. 7 and 4. 5 points with every year of schooling and during summer vacations IQ scores have shown decreases and corresponding increases during the school year (Print, 2013, p. 71) Peer influence involves the type of friends that you surround yourself with. Peer influence encompasses the dangers of simply having the wrong peers as well as peer pressure.
Particularly during impressionable years such as adolescence; peer influence and peer pressure can have a magnified affect n an individual. Teens may feel obligated to adopt certain fads and trends that their peers are taking on and the need to feel accepted and a sense of belonging can drive them to to great lengths to fit in’. Domestic life encapsulates the environment of the household. This environment is shaped very strongly by the presence of authority figures primarily these being the maternal and paternal roles. Evidently, when domestic life is stable this has profoundly positive effects on the child. A Criticism on the Genetics of Psychopathy Essay.
When the child experiences a loving and healthy lifestyle, the child is able to grow and be shaped by these positive environments. With the absence of stability in domestic life and in some cases an absence of a home at all, there can be detrimental consequences to the child. In many instances, having a ‘rough childhood’, a rocky relationship with parents, negative childhood experiences or even no childhood at all will change the path of life of an individual negatively and permanently. Culture is defined as the behaviors and beliefs characteristic to a social/ethnic/age group (Merriam-Webster, n. . Web, Seep 2013). Culture plays a large role in defining who we are and essentially the surroundings that we most associate ourselves with. It takes the shape of our everyday domestic life, our lifestyle and the society we live in. There are a whole host of cultures embedded everywhere all around the world and this is perhaps an explanation for the variation around the world. Evidence supporting Nurture The nurture argument provides some strong and irrefutable cases that point to the idea that human beings are governed strongly by environmental influences.
It is not to be denied that ultimately, we are who we are as a result of a complex interaction of both genes and environment. Despite this, increasing evidence displays that more often than not environment has a larger impact on our traits and behavior. Take the Flynn Effect as an example. It was revealed in the asses by James Flynn a political scientist, that in all the countries for which data existed, there was a rise in IQ. These were dramatic increases with ‘scores rising by about three points every decade’ and some countries where there was a ’20 point increase between one generation’ (in Print, 2012: 71).
There are a number of proposed explanations for the Flynn Effect with the more likely being the effect of the modern environment on human intelligence. Children are spending more time in school, nutrition in many countries are at a high standard and the exposure of television, books, films and media in today’s society are some of the factors that make up our ‘modern environment’ A genetic explanation for the rise in IQ has been largely discredited (even by Flynn himself). Although it may have some effect on intelligence, it is restricted because as do many other things; there are host of factors that contribute to an individual’s intelligence.
Additionally, famous conditioning studies done by John Watson in the sass (Cherry, 2005) provides some strong support for Nurturing because it demonstrates that emotional responses can be conditioned in humans through the environment. In his experiments, Watson used a 9 month old male infant dubbed ‘Little Albert’ and exposed him to several objects or stimuli. These objects include a white rat, a white rabbit, a monkey, masks, burning newspaper, etc. Before conditioning, Little Albert displayed no fear to any of these objects. Then Watson began pairing the appearance of the white rat with a loud metallic clanging sound.
This time, Albert began to cry after being shown the white rat. Psychological indignation involves encouraging a subject to behave a certain way or have a desired reaction through positive or negative reinforcement. In this case, it was negative reinforcement and fear was associated with the white rat creating a conditioned response of fear in Little Albert. A Criticism on the Genetics of Psychopathy Essay. Nurture and Psychopath Some specific cases have shown a relationship with psychopath and these are studies where the results not only strengthen the nurture debate but may also explain what goes into making a psychopath.
Print (2013) makes the point that culture and society can influence our emotions – happiness as well as sadness. These an come in the form of the more obvious cultural conditions such as war, poverty and oppression. However, even seemingly stable societies can cause us to feel negative emotions and this is through stratification. Furthermore, societies can unwittingly create psychiatric disorders including psychopath. This is done through the labeling of mental illnesses and the dire consequences on an individual who is stigmatize and marginal’s by his/her society.
A ‘mad’ person may not feel ‘mad’ or self conscious if society and science did not label him/her so. Thus, we can see the consequences of society and one’s environment on a person. He argues that whilst psychopaths are a medical category, it is also a social category reflecting our attitudes towards personalities and traits that we as a society, struggle to understand. After all, it is society that places labels on certain groups and individuals and essentially all of us are defined by our society view of what is normal. Prenatal environment is undeniably crucial in the child development and further strengthens the Nurture argument.
There is evidence to show that prenatal smoking as well as prenatal cocaine use has a statistical correlation with early childhood conduct problems especially with prenatal smoking) and problems with neurological functions. (Managua et al, 2004)(William et al, 2011). Significantly Managua and his collaborators (2004) discovered that prenatal smoking resulted in an increased risk for antisocial behavior in children. This may have some impact on psychopath because antisocial behavior is one of the signature traits of the psychopath. Domestic life can also be linked to shaping a psychopathic individual.
Studies show that the presence of maternal depression can lead to children developing ’emotional and behavioral problems’ (Kim-Cohen, 2005). It is posited that depressed mothers end to provide a lack of emotional support, poor quality interactions and create ‘stressful family contexts’. This is supported by results showing that children with depressed mothers between ages 5 and 7 displayed an increase in antisocial behavior by age 7. This can be easily linked to psychopath as the PC-R (Hare’s Psychopath Checklist) marks antisocial behavior as one of the key characteristics in determining a psychopath.
In fact, psychopath comes under the medical diagnosis of anti social personality disorders. Research has shown that personality traits correlate with your geographical location. Say you’re living in America; this corresponds to a widely different culture and society surrounding you compared to if you were living in China for example. An effort involving 100 social, behavioral and biological scientists from 56 nations sent out 9 page questionnaires to 100 men and women volunteers.
All 56 nations were grouped into the following 10 geographic regions: North America, South America, Western Europe, Eastern Europe, Southern Europe, Middle East, Africa, Oceania, South and Southeast Asia and East Asia. The questionnaires were designed to score on the 5 personality dimensions of the acronym ‘OCEAN’: Openness (are you open to new experiences? ), Conscientiousness (disciplined and dutiful), Extroversion (outgoing), Agreeableness (co-operation skills), Neurotics (are you emotionally unstable? ) (Schmitt et al, 2007). A Criticism on the Genetics of Psychopathy Essay.
If it were that genetics played a more important role in shaping an individual, it is expected that we would find personality traits evenly distributed across all cultures. However the results yielded startling cross cultural differences showing that ‘North Americans are more extroverted and less neurotic than people in East Asia. Africans are more agreeable than western Europeans… South Americans are more open to new experiences than south Asians. ‘ Print mentions that these differences also correlate with ‘economic and political variables, such as… The prevalence of status hierarchies. ‘(2013, p. 2) These cross-cultural differences signify the possibility of mental illness (as displayed in scores for neurotics), including psychopath correlating with where you live in the world. These results could potentially lead to the idea that your geographical location and corresponding culture and society could have a correlated risk of displaying psychopathic traits. Research has shown that our personality changes across a lifespan and these are marked with important life experiences which suggest that drastic changes in your lifestyle/ immediate surroundings can bring about significant changes in personality.
Psychologist Norma Han (in Print, 2013: 42) found by investigating a variety of different traits over a 50 year period, personality traits do not stabilize until people are in their ass. They have been shown to change with key life events such as marriage and employment status. In light of this, it can be argued that major negative life experiences such as a car accident can impact a person’s personality. Negative life experiences such as these may often have long term implications in the form post traumatic stress and depression.
These two chronic mental problems can encourage antisocial behavior towards other people and thus potential psychopathic traits. Another example of the strength of environmental influence is explored in Stanley Amalgam’s experiments which talk about the essence of obedience and significantly the dangers of blind obedience are. Subjects were told that the experiment was on the effects of punishment on learning and memory and their role clearly laid out as the teacher’. Their Job was to administer shocks of increasing voltage when the ‘learner’ would answer incorrectly.
The ‘learner’ was a hired actor. Amalgam’s intentions were to test how much pain an ordinary citizen would inflict on another person’ at the orders of an ‘experimental scientist’. The startling results showed that 65 percent of the subjects obeying orders punished the victim right up to the largest shock available. In the ‘Perils of Obedience’ (1974), Amalgam postulates that obedience has a fundamental characteristic that explains why normal members of society can become impelled to commit acts of evil and cruelty when instructed by an authority.
This characteristic causes the subordinate to feel an ‘instrument’ to carry out the demands of the authority. Consequently, the subordinate feels responsibility shifting entirely from him/her to the authority. Now the subject feels responsible to the authority and even how acceptably the task has been performed. This supports the Nurture debate because it suggests that capability of ‘evil’ is influenced strongly by environment. When placed in situations that obligate them to commit acts which are orally perverse, normal individuals can easily become willing instruments.
Towards psychopaths, Amalgam’s findings suggest that evil can arise even in individuals who are deemed mentally sound by society and more importantly individuals that do not have a supposed genetic predisposition to psychopathic symptoms. This greatly changes the view that psychopaths are what they are due to genetics. In addition, these findings emphasis that we ought to be more attentive to another danger in society that can arise through the power of obedience and authority.
This phenomenon has been known to re-occur many times throughout history, where wrought the power of suggestion and obedience whole countries and whole masses have been coerced and compelled to commit heinous crimes against humanity such as murder, rape and massacres. In these cases, it is more often than not that a particular group or race is being persecuted. In these instances, it has been a source of much confusion as to the innocence of the mass of people who had been instructed to carry out these acts. Are they to be Judged as mentally insane individuals?
Or simply human beings who had followed orders and ‘done their duty? Such was the case in Coachman’s trial where this heavily publicized court ruling was o decide the fate of an ex-Nazi AS-Lieutenant Colonel who facilitated the mass deportation of millions of Jewish people into ghettos and extermination camps. Doll Coachman was tried in Israel following his capture by Israeli agents in Argentina. In his testimony, Coachman demonstrates incredible normalcy – a thing that many find hard to believe considering the atrocities that he had committed.
Coachman claims that he believes he did nothing wrong and his defense for condemning millions of Jews to death was not because he hated them but because he had been under orders of the Fuehrer. (Loan, 2004, p. 22) Nurture and its Consequences Other than considering the strength of the evidence supporting the nurture debate, it is useful to postulate the potential consequences if nurture was proved to be more influential in determining psychopath than genetics. One of these consequences would be the sudden shift of attention away from human DNA and more towards environment.
Instead of tinkering away at bending DNA to our will, why not invest more attention towards looking at the effects of prenatal environment, learning environment and domestic abuse on children. Thus with the rise of nurture over nature, a rise in the importance of parenting would be expected in science and society. Another probable consequence would be the effect of nurture over nature for psychopathic individuals. The idea that some are innately programmed to be evil would give way to fresh hope that perhaps ‘evil’ in adults can be avoided by cultivating a positive environment during childhood.
This is similar to the popular What if question: what if Hitler had been accepted into art school The Nature Debate In the nature debate, it is defended that genetics have a larger impact on us as individuals than the environment. Naturists believe that psychological traits are unethically controlled and whilst the environment can have some impact, it is insignificant. Most naturists have abandoned the view that genes directly cause psychological traits and have since changed to claims that genes can only predispose us to certain behaviors.
Evidence supporting Nature and Psychopath An example of nature and biology playing an important role in determining psychopath is R. James Flair’s work on the ‘Neurological basis of psychopath (2003) reveals that studies with mortgaging scans (MR.) have shown that high levels of psychopath are linked with ‘reduced amygdaloidal volume’. This is the area of the brain where responses to fearful and sad facial expressions are processed and thus impairments in these neural structures may explain the reason why psychopaths are able to commit such transgressions against others.
However, it is important to note that the subjects investigated were not psychopathic individuals but only violent offenders. Blair notes that these differences are crucial because violent offenders still possess some morality. In addition, Blair highlights that studies done on psychopathic individuals with violent tendencies found that their frontal orate (heavily interlinked with the magical) were intact. Limitations of the Nature There is still a lot of research that provides evidence for the Nature debate, but these are more often than not methodologically flawed. A Criticism on the Genetics of Psychopathy Essay.
One example of is twin studies which have proved extremely useful in demonstrating the influence of genes and the influence of environment on human beings. The idea is that any differences between minimization (identical) twins are attributed to the environment because they share the same genetic information. Similarly, any differences between dogmatic (fraternal) wins will be attributed to genetics because fraternal twins share similar environments e. G. Through living in the same home.
But as of late, it has become evident that twin studies tend to exaggerate the genetic influence. For example, it is common for minimization twins to be mistaken for each other. Print (2013) suggests that being mistaken for each other or being treated the same will cause twins to behave more like each other. If being treated the same by other people will cause identical twins to behave more like each other, then isn’t the similarities that minimization twins caused by environmental influences?
The idea that being treated the same will yield similar behavior is supported by the research done by Sandra Scar and Louise Carter-Salesman (in Print, 2013: 38) who investigated minimization and dogmatic twins. The subjects were twins who had been mistaken about their zygotic I. E. Identical twins were misidentified as fraternal and fraternal twins misidentified as identical. They reasoned that fraternal twins mistaken for being identical would share more similarities than fraternal twins who did not have mistaken zygotic.
In their study, it was found that twins who looked more alike performed more similarly in an intelligence test. One example off twin study is when Viding and his collaborators (2005) demonstrated that psychopathic traits observable in children age 7 is under strong genetic influence. The two traits focused upon were the callous-unemotional trait (CUE) and antisocial behavior (AS). Viding explains that these 2 particular traits are usually early warning signs of psychopathic tendencies in the child.
The method Viding used to obtain results involved the use of teacher’s ratings of CUE and ABA for 3687 identical twins. They focused on the individuals who scored highly on these traits and named this ‘extreme CUE’ or ‘extreme ABA’. The scientists here were extremely careful and chose not to use parent ratings as this showed unreliability. We should be cautious about findings such as these because they do not acknowledge the possibility of the similarities between the identical twins being attributed to the fact that they are commonly treated the same.
Receiving similar treatment, as we have seen, has the potential to result in similar behavior. If this was the case, it might be that Viding results were not due to genetic influences and rather environmental influences. In defense to this, it may be argued that twin researchers not only use identical and arterial twins but also what is becoming increasingly useful is investigations done into twins raised together and twins that were raised apart. Studies investigating twins reared apart claim that identical twins reared apart show more similarities than fraternal twins reared apart.
This suggests a dominance of genetic influence over the environment as twins reared apart do not have a shared environment. A Criticism on the Genetics of Psychopathy Essay. But what many do not know is the limitations of these studies. Currently, there are 2 major registries for twins reared apart situated in Minnesota and Sweden. These are seed extensively for research and studies. However, what is not said is that the separated twins often have been in contact with each other before and during these studies. According to Print (2013, p. 9), the twins in these registrars had on average 112. 5 weeks in contact with each other and a startling 75 percent of twins had contacted each other during the separation. During this time, it is likely that the twins influenced each other We often see scientists touting around a ‘gene that codes for a particular psychological trait. ‘ When such claims are made, it is misleading to suggest hat genes can directly cause us to behave a certain manner because this is not the case!
When genes code for certain behavior, it is more correct to say that genes code for amino acids; and these amino acids are somehow involved in the production of cells which play a role in the production of behavior. It may be that these amino acids are neurotransmitters in the brain for example. In all cases, being genetically predisposed towards a psychological trait arises from a complex interaction of the environment as well as genetics. The Warrior Gene: MAO-L Recently some findings have revealed that the gene MAO-L (amniocentesis’s-low arrant) creates a predisposition to chronic violence and anger.

Little research has examined genetic and environmental contributions to psychopathic personality traits. Additionally, no studies have examined etiological connections between psychopathic traits and the broad psychopathological domains of internalizing (mood and anxiety) and externalizing (antisocial behavior, substance abuse). The current study was designed to fill these gaps in the literature.

Method

Participants were 626 pairs of 17-year-old male and female twins from the community. Psychopathic traits were indexed using scores on the Multidimensional Personality Questionnaire (MPQ). Symptoms of internalizing and externalizing psychopathology were obtained via structured clinical interviews. Structural equation modeling was used to estimate genetic and environmental influences on psychopathic personality traits as well as the degree of genetic overlap between these traits and composites of internalizing and externalizing. A Criticism on the Genetics of Psychopathy Essay.

Results

Twin analyses revealed significant genetic influence on distinct psychopathic traits (Fearless Dominance and Impulsive Antisociality). Moreover, Fearless Dominance was associated with reduced genetic risk for internalizing psychopathology, and Impulsive Antisociality was associated with increased genetic risk for externalizing psychopathology.

Conclusions

These results indicate that different psychopathic traits as measured by the MPQ show distinct genetically based relations with broad dimensions of DSM psychopathology.

Psychopathy is a disorder marked by a constellation of maladaptive personality traits. Within this literature, some scholars have postulated that the disorder comprises distinct facets including interpersonal-affective traits (e.g. superficial charm, manipulativeness, poverty of affect) and antisocial traits (e.g. impulsivity, aggression; Hare, 1991, 2003; Cooke & Michie, 2001). In terms of etiology, while many studies have investigated phenotypes related to psychopathy (e.g. delinquency, antisocial behavior), very little is known about the genetic and environmental structure of psychopathy per se, as virtually no studies have investigated the genetic and environmental contributions to the interpersonal-affective traits (see Blonigen et al. 2003 for an exception).

In the present investigation, we examined the biometric structure of the interpersonal-affective and antisocial traits of psychopathy using a community sample of male and female adolescent twins. Previous findings suggest that these traits exhibit divergent phenotypic relations with internalizing (Int) (mood and anxiety) and externalizing (Ext) (antisocial behavior and substance abuse) psychopathology (Patrick et al. 2003; Benning et al. in press). Therefore, we also examined the degree of genetic overlap between psychopathic traits and these broader psychopathological domains to further clarify the underlying etiological bases of psychopathy and its relations with common mental disorders.

Psychopathy: description and behavior genetic investigations

The predominant view of psychopathy derives from the personality-based clinical conceptions of the syndrome (Cleckley, 1941/1976; Karpman, 1948; McCord & McCord, 1964) in which core interpersonal-affective deficits are emphasized (e.g. superficial charm, absence of nervousness, guiltlessness, pathologic egocentricity, dishonesty) rather than the commission of specific antisocial acts. Other theorists (Karpman, 1941; Lykken, 1957; Blackburn, 1975) have elaborated on this conceptualization of psychopathy to include primary and secondary subtypes, with the former characterized by low anxiety and antisocial behavior due to a lack of conscience, and the latter characterized by negative affect and impulsivity, and the expression of neurotic conflict as antisocial behavior.

Similar themes are embedded in the most prominent assessment instrument in the field, the Psychopathy Checklist – Revised (PCL-R; Hare, 1991, 2003), a semi-structured interview designed to assess these classic clinical descriptions of psychopathy in incarcerated settings. Factor analytic research (Harpur et al. 1989) has established that this measure captures two distinct facets of the syndrome: Factor 1 is marked by interpersonal-affective traits, and Factor 2 is marked behavioral indicators of antisocial deviance.1 Interestingly, the external correlates of Factors 1 and 2 strongly resemble clinical descriptions of primary and secondary psychopathy, respectively (Blackburn, 1975, 1996).

Although the interpersonal-affective and antisocial facets of psychopathy have received extensive empirical investigation, there is a lack of concomitant research exploring their genetic and environmental underpinnings.A Criticism on the Genetics of Psychopathy Essay.  A primary reason for this is that the item content, use of collateral file information, and lengthy administration of the PCL-R were designed for incarcerated populations and are not conducive for use in epidemiological samples of twins or adoptees. Moreover, most behavior genetic studies have investigated behavior-based phenotypes [e.g. antisocial personality disorder (APD), juvenile delinquency, criminality; Mednick et al. 1984; Cloninger & Gottesman, 1987; DiLalla & Gottesman, 1989; Lyons et al. 1995; McGuffin & Thapar, 1998; Jacobson et al. 2000; Taylor et al. 2000; Goldstein et al. 2001] which preferentially index the antisocial traits of psychopathy and are, therefore, limited in their ability to address the etiology of the core interpersonal-affective features. This is a potentially critical limitation given that some researchers (e.g. Karpman, 1948; Mealey, 1995; Porter, 1996) have theorized that primary and secondary psychopathy may differ in their etiology with the former arising from a constitutional or genetic disposition, and the latter as a manifestation of environmental influences (e.g. parental rejection, abuse, poor socialization). However, such assertions have not been subject to empirical investigation with genetically informative data (see Skeem et al. 2003).

Assessment of psychopathy in the self-report domain

Given the limitations of the PCL-R, some scholars have turned to the self-report domain to investigate psychopathy within the general population. However, most self-report indices preferentially tap the antisocial traits of the disorder (Hare & Cox, 1978; Lilienfeld, 1994, 1998). A self-report measure that has shown potential as an index of both trait dimensions is the Psychopathic Personality Inventory (PPI; Lilienfeld & Andrews, 1996). The PPI was designed to capture a range of psychopathic personalitytraits rather than overt antisocial behaviors. Based on evidence suggesting that it captures both the interpersonal-affective and antisocial traits of psychopathy (Lilienfeld & Andrews, 1996; Poythress et al. 1998), Benning et al. (2003) factor-analyzed PPI subscale scores from a community sample of adult men. Two dominant, orthogonal factors were extracted whose external correlates resembled those of the PCL-R factors. The first factor (PPI-I: Fearless Dominance) was marked by social potency, stress immunity, and fearlessness; core features of the interpersonal-affective traits and analogous to primary psychopathy. The second factor (PPI-II: Impulsive Antisociality) was marked by negative emotionality (aggression, alienation) and low behavioral constraint (impulsivity, sensation seeking), and is analogous to secondary psychopathy. Subsequent validation studies have demonstrated that both PPI factors demonstrate convergent and discriminant validity for the interpersonal-affective and antisocial traits of psychopathy (Benning et al. 2003; Lilienfeld & Skeem, 2004).

Measuring psychopathy via normal personality

A notable finding regarding the PPI factors is that they can be measured effectively using the Multidimensional Personality Questionnaire (MPQ, Tellegen, in press), a broadband measure of personality. Benning et al. (2003) found that the primary scales of the MPQ captures a substantial portion of variance in these factors (R=0.89 for Fearless Dominance; 0.84 for Impulsive Antisociality).2 Recently, Benning et al. (in press) examined the criterion-validity of these factors as estimated from the MPQ in two community samples and a sample of male prisoners. Fearless Dominance was negatively related to social phobia and depression as well as self-reported fear, distress, and anxiety, and correlated positively with indices of fearlessness, sociability, thrill-adventure seeking, narcissism, and PCL-R Factor 1 (Benning et al. in press). Conversely, Impulsive Antisociality was positively associated with substance dependence, child and adult antisocial behavior, self-reported anxiety, disinhibition, and boredom susceptibility, and PCL-R Factor 2, and inversely related to socialization (Benning et al. in press). A Criticism on the Genetics of Psychopathy Essay.

Overall, the external correlates of these constructs are consistent across community and offender samples and largely resemble the external correlates of the PCL-R factors. This suggests that the MPQ-estimated psychopathy factors may index related constructs within the domain of normal personality. Given the feasibility of administering the MPQ in large epidemiological samples of twins or adoptees, the findings of Benning et al. (in press) provide a foundation for studying the genetic and environmental underpinnings of psychopathy within the general population. Accordingly, our first objective was to examine if there is a differential heritability to these psychopathic traits as has been theorized in the literature (see Skeem et al. 2003).

Phenotypic relations with psychopathology: Int and Ext

A notable finding regarding Fearless Dominance and Impulsive Antisociality is that they exhibit divergent phenotypic relations with Int and Ext psychopathology (Benning et al. in press). These dimensions represent systematic covariation among common DSM disorders with the former reflecting the covariation among unipolar mood and anxiety (Vollebergh et al. 2001) and the latter representing the covariance among child and adult antisocial behavior and substance dependence (Krueger et al. 2002). With respect to Int, self-reported fear and anxiety were inversely related to Fearless Dominance, whereas Impulsive Antisociality correlated positively with such measures (Benning et al. in press). Diagnostically, Fearless Dominance was negatively associated with social phobia, simple phobia, and major depression, whereas Impulsive Antisociality was positively associated with major depression (Benning et al. in press). With respect to Ext, Impulsive Antisociality was positively associated with child and adult antisocial behavior and substance dependence, while Fearless Dominance was relatively unrelated to these disorders with the exception of a positive correlation with adult antisocial behavior in a sample of adult men (Benning et al. 2003).

Despite these diverging phenotypic associations with indicators of Int and Ext, the extent to which psychopathic traits relate to these broad factors of psychopathology at a genetic level remains unclear. Thus, a second aim of the present investigation was to estimate the degree of genetic overlap between psychopathic traits and factors of Int and Ext.A Criticism on the Genetics of Psychopathy Essay.  Given the inverse association between Fearless Dominance and indices of Int, and the positive association between Impulsive Antisociality and indices of Ext, we hypothesized a parallel genetic relationship among these variables.

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METHOD

Participants

Participants were 17-year-old male and female twins from the Minnesota Twin-Family Study (MTFS). The MTFS is an ongoing epidemiological-longitudinal study examining the genetic and environmental factors that contribute to the development of substance abuse and related psychopathology in reared together, same-sex twins and their parents. A comprehensive description of the objectives and design of the MTFS has been provided elsewhere (Iacono et al. 1999; Iacono & McGue, 2002). The present investigation involved male twins born between the years 1972–1978, and female twins born between the years 1975–1979. Participating twins were predominately Caucasian (98%), which is consistent with the demographics of Minnesota when the twins were born. Families were excluded from participation if they lived further than a day’s drive from our laboratories in Minneapolis, or if either twin had a serious intellectual or physical disability that would preclude him or her from completing the day-long, in-person assessment. Following the intake assessment, the sample size consisted of 289 male (nMZ=188, nDZ=101) and 337 female (nMZ=223, nDZ=114) twin pairs.

Zygosity was determined by the agreement of three separate estimates: (1) a standard zygosity questionnaire completed by parents, (2) an evaluation by MTFS staff regarding the physical similarity between the twins, and (3) an algorithm comparing twins on ponderal and cephalic indices and fingerprint ridge counts. In situations in which the three estimates did not agree, a serological analysis was performed.

Assessment

Psychopathic personality traits

Because PPI data were not available for members of the current sample, factor scores on Fearless Dominance and Impulsive Antisociality were estimated using the 11 primary scales of the 198-item version of the MPQ. Specifically, regression weights derived from a community sample of adult men (n=353; Benning et al. 2003), were applied to MPQ primary scale scores to estimate factor scores for these psychopathy constructs.3

All families were mailed the MPQ prior to their intake assessment. Participants were asked to bring their completed MPQ with them to their in-person visit. If the MPQ was not completed either upon arrival for their intake assessment or by the end of the day-long visit, participants were asked to complete it at home and return it by mail. MPQ data were available for 1122 individuals (men=502, women= 620). A Criticism on the Genetics of Psychopathy Essay. Consistent with previous investigations (Benning et al. 2003, in press; Patrick, 2004), Fearless Dominance and Impulsive Antisociality were uncorrelated in men and women, r=0.03, n.s. and 0.00, n.s. respectively.

Int and Ext psychopathology

All twins were interviewed in-person for lifetime presence of several common mental disorders according to DSM-III-R criteria (the version of the diagnostic manual current at intake; APA, 1987) including: major depression, social phobia, simple phobia, conduct disorder, antisocial personality disorder (APD), and alcohol, nicotine, and drug dependence. Trained individuals with either a bachelor’s or a master’s degree in psychology conducted the interviews. A modified version of the Structured Clinical Interview for DSM-III-R (Spitzer et al. 1990) was used to assess major depression, social phobia, and simple phobia. Male twins were not assessed for Int disorders at intake, but were at the age 20 follow-up assessment (n= 470–474). Therefore, for men, relations with Int disorders refer to lifetime symptoms assessed at age 20. A structured interview designed by MTFS staff (Holdcraft et al. 1998) was administered to assess symptoms of conduct disorder and adult antisocial behavior (the adult criteria for APD). The Substance Abuse Module of the Composite International Diagnostic Interview (Robins et al. 1987) was used to assess symptoms of alcohol, nicotine, and illicit drug dependence. The drug assessment included amphetamines, cannabis, cocaine, hallucinogens, inhalants, opioids, phencyclidine, and sedatives. The substance for which the participant evinced the maximal number of symptoms was used as their number of drug dependence symptoms. Additionally, mothers reported on symptom presence for conduct disorder and substance dependence disorders in both twins using the parent version of the Diagnostic Interview for Children and Adolescents –Revised (Reich & Welner, 1988). Symptoms were deemed present if reported by either the mother or the twin.

Following the intake assessment, all diagnostic interview data were reviewed in a case conference by at least two graduate students with advanced training in descriptive psychopathology and differential diagnosis. All items scored positive, or about which there was ambiguity regarding scoring, were reviewed with the aid of audiotapes from the interviews in order to achieve a consensus regarding symptom presence. Excellent reliability regarding this consensus process has been previously reported (Iacono et al. 1999) with kappas ranging from 0.78 (social phobia) to 0.95 (adult antisocial behavior). A Criticism on the Genetics of Psychopathy Essay.

In order to examine the genetic overlap between psychopathic personality traits and psychopathology, an Int variable was calculated by taking the average standardized (via z-score transformation) symptom count score among major depression, social phobia, and simple phobia. An Ext variable was calculated in the same manner using symptoms of adult antisocial behavior, conduct disorder, and alcohol, nicotine, and drug dependence. Int and Ext were significantly correlated for women, r=0.21, p<0.001, but not men, r=0.00, n.s.

Data analysis

Model-fitting analyses in the present study involved twin methodology. Twin studies utilize the difference in proportion of alleles shared between monozygotic (MZ) and dizygotic (DZ) twin pairs to estimate the relative genetic and environmental contributions to observed phenotypes. This methodology typically involves the estimation of additive genetic (a2), shared environmental (c2), and non-shared environmental effects (e2). Additive genetic influences involve the summation of individual genes across loci. MZ (identical) twins share 100% of their additive genetic effects while DZ (fraternal) twins share 50% of these effects, on average. Thus, MZ correlations will be roughly twice as large as the DZ correlations if the phenotype in question is primarily due to additive genetic contributions. Shared environmental effects (c2) are environmental effects common to both members of a twin pair that produce similarities between them (e.g. family environment). Substantial c2 effects on a phenotype would generate MZ and DZ correlations similar in magnitude. Non-shared environmental effects (e2) are environmental factors unique to each member of a twin pair that tends to create differences between the twins.

To examine the etiological connections between psychopathic traits and Int and Ext, we fit a Cholesky decomposition to the data, which parses the individual variance of each phenotype as well as the covariance between phenotypes into genetic, shared, or non-shared environmental factors. Using this approach, the amount of shared variance between the psychopathy traits and Int or Ext was partitioned into its genetic and environmental components. This allows for the estimation of the proportion of phenotypic covariance between the psychopathy traits and Int or Ext that is due to genetic, shared, or non-shared environmental effects. Moreover, these effects can then be standardized on their respective variances to compute genetic, shared, or non-shared environmental correlations. These estimates indicate the degree to which the genetic, shared, or non-shared environmental effects of one variable are correlated with that same effect on another variable.

All model-fitting analyses were conducted using Mx, a structural-equation modeling program (Neale et al. 2002). We fit models to the raw data using maximum-likelihood (‘all data’) estimation, which corrects for potential biases due to missing data. Specifically, this technique uses all available information to estimate values for the missing data and then adjusts for the imprecision of the estimated values. When first fitting models to raw data, all means, variances, and covariances are freely estimated to get a baseline index of fit (minus twice the natural log-likelihood of the data; −2 ln L). A comparison of the −2 ln L under this unrestricted model with the −2 ln L under more restrictive biometric models yields a likelihood-ratio χ2 goodness-of-fit test (Δχ2). To guide selection of the best-fitting model, this Δχ2 was then converted to the Akaike information criterion (AIC=χ2 − 2 df; Akaike, 1987). The AIC is a measure of model fit relative to parsimony and is used to assess the comparative fit among a series of competing biometric models.

Generally, parameter estimates could be constrained across men and women without a significant decrement in fit. However, some significant gender differences were observed.  A Criticism on the Genetics of Psychopathy Essay.Therefore, we present results separately for men and women, as well as estimates from combined models in which the unstandardized parameters were equated across the genders.

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RESULTS

Etiological structure of psychopathic traits

Twin correlations estimated from baseline models for univariate biometric models are presented in Table 1. For both men and women, the twin correlations for Fearless DominanceImpulsive Antisociality, Int, and Ext are generally consistent with an additive model of inheritance (MZ correlations approximately twice that of DZ correlations). To test for mean differences across the genders, a model allowing the means to vary was compared to a model in which the means were constrained to be equal. Within this model, men exhibited significantly greater mean levels of psychopathic traits and Ext symptoms than women (χ2(1)=107.7, 53.6, 30.0, all p’s <0.001), for Fearless DominanceImpulsive Antisociality, and Ext respectively, while women exhibited significantly greater mean levels of Int symptoms (χ2(1)=59.7, p< 0.001). Therefore, we allowed the means to vary across gender for all biometric models. Results of the univariate biometric models were consistent with impressions from the twin correlations. For both Fearless Dominance and Impulsive Antisociality, as well as for Int and Ext, the AIC was smallest for the AE model (additive genetic and non-shared environment).4

Table 1

Twin correlations for psychopathic personality traits, internalizing, and externalizing

Men


Women


Combined


MZ (95% CI) DZ (95% CI) MZ (95% CI) DZ (95% CI) MZ (95% CI) DZ (95% CI)
Fearless Dominance 0.42 (0.29–0.54) 0.20 (−0.01 to 0.40) 0.45 (0.34–0.56) 0.21 (0.02 to 0.39) 0.44 (0.36–0.52) 0.20 (0.06–0.34)
Impulsive Antisociality 0.51 (0.39–0.61) 0.17 (−0.05 to 0.38) 0.49 (0.37–0.59) 0.28 (0.10 to 0.44) 0.50 (0.41–0.57) 0.24 (0.10–0.37)
Internalizing 0.48 (0.34–0.59) 0.19 (−0.04 to 0.40) 0.29 (0.17–0.41) 0.14 (−0.05 to 0.32) 0.35 (0.25–0.44) 0.15 (0.01–0.29)
Externalizing 0.70 (0.62–0.77) 0.44 (0.27 to 0.59) 0.68 (0.60–0.74) 0.26 (0.08 to 0.42) 0.68 (0.63–0.73) 0.37 (0.25–0.48)

MZ, Monozygotic twins; DZ, Dizygotic twins; CI, confidence interval.

All twin correlations were estimated by fitting models to the raw data using maximum-likelihood estimation, which corrects for any potential biases due to missing data. n=1252 individuals from 626 twin pairs, some with missing data. Internalizing was calculated by taking the average standardized (via z-score transformation) symptom count score among major depression, social phobia, and simple phobia.A Criticism on the Genetics of Psychopathy Essay. Externalizing was calculated in the same manner using symptoms of adult antisocial behavior, conduct disorder, and alcohol, nicotine, and drug dependence. Combined refers to models in which parameters were equated across the genders.

Table 2 provides the heritability estimates from the best-fitting models. In the combined sample, roughly half the variance in both Fearless Dominance and Impulsive Antisociality was due to additive genetic effects. Moreover, the heritability was moderate for Int and strong for Ext. The heritability estimates for all the variables was very similar for men and women, although a sex difference for Int approached significance, χ2(1)=3.72, p=0.054. There was virtually no evidence of shared environmental contributions to any of the phenotypes. Even when shared environmental effects were included in the model, almost all parameter estimates were zero.

Table 2

Heritability estimates from best-fitting univariate twin models for psychopathic personality traits, internalizing, and externalizing

Men


Women


Combined


Heritability (95% CI) Heritability (95% CI) Heritability (95% CI)
Fearless Dominance 0.46 (0.32–0.57) 0.45 (0.34–0.54) 0.45 (0.37–0.53)
Impulsive Antisociality 0.51 (0.39–0.62) 0.48 (0.37–0.57) 0.49 (0.41–0.56)
Internalizing 0.49 (0.35–0.60) 0.31 (0.18–0.43) 0.36 (0.27–0.45)
Externalizing 0.76 (0.70–0.81) 0.68 (0.60–0.74) 0.73 (0.68–0.77)

n=1252 individuals from 626 twin pairs, some with missing data. CI, confidence interval. The heritability for all variables are due to additive genetic effects. Combined refers to models in which the unstandardized parameters were equated across the genders.

Phenotypic and genetic associations between psychopathic traits and psychopathology

Table 3 contains the phenotypic correlations between the psychopathy variables and symptom counts for each mental disorder as well as the Int and Ext composite variables. For both men and women, Fearless Dominance was negatively related to each Int disorder, whereas Impulsive Antisociality was positively correlated with symptoms of major depression. The Int composite was also negatively correlated with Fearless Dominance for both genders. In women, Int was significantly correlated with Impulsive Antisociality, but this gender difference was not significant. For both men and women, Impulsive Antisociality was positively correlated with each Ext disorder. In men, Fearless Dominance was also weakly but significantly correlated with symptoms of adult antisocial behavior, conduct disorder, and nicotine dependence. For both men and women, the Ext composite was positively correlated with Impulsive Antisociality. In men, but not women, Ext was also significantly correlated with Fearless Dominance, but this gender difference was not significant. A Criticism on the Genetics of Psychopathy Essay.

Table 3

Correlations between psychopathic personality traits and symptoms of common mental disorders

Men


Women


Symptom counts Fearless Dominance Impulsive Antisociality Fearless Dominance Impulsive Antisociality
Major Depression −0.11 0.15* −0.09 0.21***
Simple Phobia −0.13* −0.02 −0.16** 0.05
Social Phobia −0.21** −0.02 −0.24*** 0.04
Adult Antisocial Behavior 0.14* 0.36*** 0.06 0.38***
Conduct Disorder 0.15* 0.30*** 0.04 0.30***
Alcohol Dependence 0.09 0.23*** −0.02 0.29***
Nicotine Dependence 0.15* 0.25*** −0.02 0.36***
Drug Dependence 0.04 0.21** 0.10 0.26***
Internalizing −0.25*** 0.05 −0.26*** 0.16**
Externalizing 0.15* 0.36*** 0.04 0.40***

Correlations were estimated by fitting models to the raw data using maximum likelihood. n=1252 individuals from 626 twin pairs, some with missing data. Significance levels were adjusted by weighting each twin one-half to account for the correlated nature of the observations.

*p<0.05,
**p<0.01,
***p<0.001.

The genetic correlations between each psychopathy variable and Int and Ext are provided in Table 4. Consistent with the phenotypic findings, Fearless Dominance and Impulsive Antisociality evinced a divergent pattern of associations with Int and Ext. For both genders, Fearless Dominance exhibited a moderate negative genetic correlation with Int. Moreover, further analysis revealed that 66% of the phenotypic covariance between these variables was due to genetic contributions. Conversely, Impulsive Antisociality exhibited a moderate positive genetic correlation with Ext, with 76% of the phenotypic covariance between these variables due to genetic factors. In women, but not men, there was a moderate genetic correlation between Impulsive Antisociality and Int, and this gender difference was significant, χ2(1)= 5.77, p=0.016. Moreover, 89% of the phenotypic association between these variables in women was due to genetic effects.A Criticism on the Genetics of Psychopathy Essay.  This indicates that for women, genetic effects that contribute to Impulsive Antisocialityincrease the risk for the expression of both Int and Ext symptoms. In men, but not women, there was a moderate genetic correlation between Fearless Dominance and Ext, and this gender difference was also significant, χ2(1)=6.89, p=0.009, with 100% of the phenotypic covariance due to genetic factors. This indicates that for men, genetic effects that contribute to Fearless Dominance also contribute to the expression of Ext symptoms.5

Table 4

Genetic correlations between psychopathic personality traits, internalizing, and externalizing

Internalizing


Externalizing


Men


Women


Combined


Men


Women


Combined


rg (95% CI) rg (95% CI) rg (95% CI) rg (95% CI) rg (95% CI) rg (95% CI)
Fearless Dominance 0.40 (−0.64 to −0.16) 0.39 (− 0.63 to −0.15) 0.40 (−0.57 to −0.22) 0.36 (0.17 to 0.56) 0.01 (−0.16 to 0.19) 0.16 (0.04 to 0.29)
Impulsive Antisociality −0.03 (−0.27 to 0.20) 0.38 (0.14 to 0.64) 0.20 (0.03 to 0.37) 0.45 (0.28 to 0.60) 0.52 (0.37 to 0.65) 0.49 (0.38 to 0.59)

rg, Genetic correlation; CI, confidence interval.

Correlations in bold are significant (confidence intervals do not include zero). Correlations in bold and italicized are significant and significantly different for men and women. Combined refers to models in which the unstandardized parameters were equated across the genders.

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DISCUSSION

Etiological structure of psychopathic traits: conceptual implications

Behavior genetic studies of psychopathy have been virtually absent in the literature with most investigations only addressing phenotypes related to antisocial behavior (i.e. criminality, juvenile delinquency, APD) rather than the interpersonal-affective traits of the syndrome. However, behavior genetic studies of both are vital given that some scholars (e.g. Karpman, 1948) have posited that primary psychopathy may reflect stronger genetic influences than secondary psychopathy. The present investigation is significant in that it examined the relative genetic and environmental contributions to both the interpersonal-affective (Fearless Dominance) and antisocial (Impulsive Antisociality) traits of psychopathy as measured by the MPQ. The results suggest that these traits are equally and substantially heritable with each accounting for roughly half of the total variance in both men and women. Furthermore, in accordance with their phenotypic independence, Fearless Dominance and Impulsive Antisociality were also genetically uncorrelated for both men (rg=0.12, n.s.) and women (rg=−0.05, n.s.) in the present study.

Collectively, the current data suggest that Fearless Dominance and Impulsive Antisociality may derive from separate etiological processes that are substantially genetic in nature. On a theoretical level, these findings could have wider implications for conceptualizations of the psychopathy construct. A Criticism on the Genetics of Psychopathy Essay. Specifically, in the general population, psychopathy may consist of independently derived maladaptive personality traits that in certain individuals may combine to form a particularly virulent phenotype. Notably, this conceptualization is consistent with the ideas of some personality theorists who view personality disorders as a configuration of certain maladaptive traits (see Grove & Tellegen, 1991).

Associations between psychopathic traits and psychopathology

One of the central findings from the current study was the diverging genetic associations between psychopathic traits and broad factors of psychopathology. First, Fearless Dominance demonstrated a significant negative genetic correlation with an Int composite, a finding consistent with prior evidence of an inverse relationship between the interpersonal-affective facet of psychopathy and self-reported anxiety (Harpur et al. 1989; Patrick, 1994, 1995; Frick et al. 1999, 2000). The present findings are an extension of this work to DSM disorders and demonstrate that genetic influences on Fearless Dominance may provide a resiliency to developing a broad range of Int psychopathology.

Impulsive Antisociality, on the other hand, exhibited a positive genetic correlation with an Ext composite, which is consistent with previous data showing specific relations between PCL-R Factor 2 and substance dependence (Smith & Newman, 1990; Reardon et al. 2002), APD (Harpur et al. 1989), and a latent Ext factor (Patrick, 2003). Given the current findings, the relationship between Impulsive Antisociality and Ext appears to be largely mediated by genetic contributions such that heritable influences to these psychopathic traits may increase one’s vulnerability to a spectrum of disorders marked by disinhibition. A Criticism on the Genetics of Psychopathy Essay.

It is also worth noting that sex differences were found in the genetic correlations between the psychopathic traits and psychopathology with Fearless Dominancegenetically correlated with Ext in men only, and Impulsive Antisociality genetically correlated with Int in women only. This pattern of relations was roughly similar to the phenotypic associations among the variables and suggests that the etiological connections between psychopathic traits and Int and Ext may differ somewhat by gender. Despite the novelty of these findings, further replication of these gender differences is required before drawing any firm conclusions.

Overall, the genetic correlations from the present study help to elucidate the etiological boundaries of psychopathy. The findings suggest that future investigations on the etiology of the syndrome can be informed by an understanding of the common genetic risk factors for psychopathy and Int and Ext rather than simply examining the specific genetic influences on psychopathy. Although genetic links between personality and psychopathology have been repeatedly observed (Carey & DiLalla, 1994; Slutske et al. 2002; Krueger & Tackett, 2003), such findings are relatively novel with respect to the psychopathy literature and demonstrate that different psychopathic traits show distinct genetic relations with broad dimensions of psychopathology.

In terms of the classic clinical conceptions of psychopathy, the finding of divergent genetic relations with distinct psychopathological syndromes aligns closely with Cleckley’s paradoxical description of the psychopath (1941/1976). Specifically, the clinical profile delineated by Cleckley includes several features of overt adjustment (e.g. superficial charm and good intelligence, absence of nervousness or psychoneurosis, suicide rarely carried out) which serve to mask a severe and underlying behavioral pathology in the psychopath (e.g. impulsive antisocial behavior, irresponsibility, promiscuity, failure to follow any life plan). The present findings of divergent genetic relations with distinct psychopathological domains suggests the possibility that this paradoxical presentation may reflect the confluence of two distinct etiological processes; one which serves as a protective factor to Int distress and is phenotypically expressed as adjustment, the other which confers a vulnerability to chronic behavioral deviance.

 

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Limitations and future directions

Some limitations are worth noting. First, we utilized a normal range personality measure to index psychopathic traits rather than the PCL-R, the standard assessment tool for psychopathy in prison samples. A Criticism on the Genetics of Psychopathy Essay. However, there is compelling evidence to suggest that psychopathy can be captured well within structural models of personality (Patrick, 1994, 1995; Widiger & Lynam, 1998; Miller et al. 2001; Verona et al. 2001; Lynam, 2002; Hicks et al. 2004). Moreover, the use of an omnibus personality measure to index psychopathic traits has several advantages, most notably of which is the ability to investigate psychopathy within the general population as opposed to incarcerated or clinical samples. Nonetheless, Benning et al. (in press) do note that the MPQ psychopathy constructs are not intended to be isomorphic or synonymous with the PCL-R factors but instead represent an alternative and complementary conceptualization which relates closely to the personality-based clinical conceptions of psychopathy (cf. Cleckley, 1941/1976).

Second, despite the advantages of our sample (e.g. community sample, men and women), we utilized adolescents (17 years old) rather than adults to examine the heritability and underlying genetic relations of psychopathy. Thus, future investigations are needed to examine whether the present findings will generalize to an adult sample.

In summary, both Fearless Dominance and Impulsive Antisociality (analogous to primary and secondary psychopathy, respectively) have substantial genetic influences with the former conferring a genetic resiliency to Int disorders, and the latter reflecting a genetic vulnerability to Ext psychopathology. This provides construct validation for the notion of psychopathic traits as deriving from separate etiological processes (cf. Patrick, 2001) given that they exhibited convergent and discriminant relations with two distinct domains of psychopathology.

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Acknowledgments

This research was supported in part by USPHS grant nos. AA00175, AA09367, DA05147 and MH65137. Daniel M. Blonigen and Brian M. Hicks are supported by the NIMH training grant MH17069. This work was completed by Daniel M. Blonigen in partial fulfillment of the requirements for the degree of Masters of Arts at the University of Minnesota under the supervision of Robert F. Krueger and Christopher J. Patrick. A Criticism on the Genetics of Psychopathy Essay.