What Causes Psychopathy?

There is much disagreement as to whether psychopathy is a function of neurological factors or the result of some aspect of environment.

A study of 1,000 boys in New Zealand found a version of a gene that is linked with antisocial behaviour but that only appears to lead to criminality when its possessor is raised in an abusive environment. While this particular interaction provides a basis for criminality but not necessarily psychopathy, it does illustrate the importance of both nature and nurture in the expression of personality. Evidence suggests that nature, or heredity, accounts for approximately 50% of the expression of psychopathic traits, and environment the remainder.

Nature: Psychopathic Brains Work Differently

There is evidence that psychopathy is to some degree a heritable neurological problem. Studies have shown that:

    • Psychopaths don’t have the same physiological responses to fear that constrain the behaviour of normal people, such as rapid heartbeat, sweating, dry mouth, trembling and muscle tension.
    • Psychopaths don’t have physiological responses to emotionally charged words such as “love” and “death” the way regular people do, suggesting that they process emotional stimuli differently.
    • When one identical twin is psychopathic, the other is more likely to be psychopathic than those in the general population.
    • Adoption studies indicate that children can inherit psychopathic traits from a psychopathic parent even when they are raised by different parents.
    • When compared to non-psychopaths, differences have been found in a number of brain chemicals among psychopaths.

Some individuals who sustain damage to the frontal lobes exhibit behavioural similarities to psychopaths, such as poor long-term planning, shallow affect, aggressiveness, low tolerance for frustration and impulsivity. However, research has not found brain damage in diagnosed psychopaths.

Nurture: Psychopathic Traits May Be Exacerbated by Abuse

It is now well-known that those who are abused and traumatized in childhood are more likely to abuse others in adulthood (though it should be noted that the majority of abuse victims break the cycle and do not go on to become perpetrators). Unfortunately, this has made it easier for psychopaths to do what they do best—play on the sympathies of others—by claiming to have suffered abusive childhoods. But psychopaths are just as likely to have come from loving, nurturing homes as from abusive ones, and many abused children do not grow up to be psychopaths.

Although abuse can worsen existing psychopathic traits, it does not cause psychopathy. However, it can shape the way in which this personality disorder manifests. A psychopath raised in a loving home is more inclined to become a shady businessman, a romantic user or a nonviolent criminal, whereas one raised in a violent, neglectful home is more likely to become a violent criminal.

Children who suffer from a lack of attachment due to early deprivation and neglect often exhibit symptoms similar to those of the psychopath including law breaking and cruelty. However, they can be distinguished by a propensity for psychological distress, anxiety and low self-esteem, in contrast to the psychopath who has a high opinion of himself and is not inclined to suffer from anything other than frustrated desires. Also, while psychopaths usually work hard at appearing normal in order to manipulate people, those with attachment disorder are more likely to be chronically hostile and off-putting, swinging between belligerence and desperate neediness rather than exhibiting the surface charm of the psychopath. Additionally, the majority of psychopaths do not suffer severe early childhood deprivation.

Social Forces: Some Aspects of Culture and Society May Promote Psychopathic Behaviour

Many criminologists and sociologists believe that psychopathy is caused entirely by social forces, which include not only childhood home life but also the broader social environment. There is some support for this theory in the fact that certain cultures have a higher incidence of psychopathy than others. Places such as the United States where the incidence is as high as 4% and increasing steadily ascribe to an individualist, self-promoting ethic, whereas places where the incidence is just 0.03-0.14%, such as Japan and China, favour an ethos of connectedness and personal responsibility.

Psychopaths exist in all cultures, even the relatively isolated Inuit, who view them as irredeemable and have traditionally dealt with them by shoving them off ice flows. It is possible that a similar percentage of people are born with the innate tendency for psychopathy in every culture. However, in some places all elements of the social environment strongly discourage the expression of the associated behavioural traits. In other words, being a psychopath is more likely to pay off in America than it is in Japan, so the uglier traits are more inclined to be expressed in one place and suppressed in another.

Evolution and Natural Selection: Psychopathy May Confer Some Survival Advantages

There are two potential strategies for getting genetic material into the next generation. The first is to have few children and take very good care of them in the hope that they will survive to reproduce. A second strategy is to have as many children as possible in the hope that even if you don’t care for them, at least some will survive into adulthood. Psychopaths follow the second strategy.

Psychopaths are notoriously irresponsible when it comes to birth control. They also tend to be sexually promiscuous, and to abandon lovers and families regularly when they move onto the next conquest. Though they tend to have many children, most don’t take care of them, and those that do often abuse them in some way. Even if their children die through neglect (which is particularly common among psychopathic mothers), they are likely to have more. Diane Downs, killer of her own children, worked as a surrogate mother. Another female psychopath said chillingly, “I can always have another,” after one of her lovers beat her young daughter to death.

Those with psychopathic personality disorder are found in all walks of life, from white collar criminals to petty thieves. A significant proportion of wife beaters, rapists, scam artists, organized criminals, doctors who have had their licenses taken away, unscrupulous businesspeople, terrorists, child abusers, professional gamblers, mercenaries, cult leaders, and serial killers are sociopaths.

Promiscuous, charming, and careless about birth control, psychopaths often have many children. Because they are unrestrained by conscience, they often come out on top in social interactions. So why has evolution not favoured the psychopath over those capable of guilt, empathy, and self-restraint?

Psychopaths suffer from a profound emotional poverty that renders them unable to experience genuine love or compassion. They will never be driven by high spiritual motivations or a desire to serve humanity, and they suffer a constant, aggravating sense of boredom that can only be mitigated by taking increasingly dangerous risks. Self-obsession can lead to paranoia and hypochondria, and even those with talent are not inclined achieve anything substantial because they lack the self-discipline to sustain effort over the long term. Disconnected from others, they are adrift on a sea of meaninglessness.

Sociopaths miss out on what gives meaning to the lives of regular people. However, a life without meaning, while unappealing to most, shouldn’t be enough to knock psychopaths out of the gene pool. Rather, it is the propensity to take excessive risks and harm others that keeps their numbers low. Psychopaths often fall victim to either their own recklessness or violent retaliation from those they have mistreated.

Because they lack the inhibitory mechanisms of fear and guilt, psychopaths take foolhardy risks and don’t plan ahead. As a result, they’re inclined to end up broke, jailed, injured, alone, or the victims of fatal violence. Many dictators and criminals have wound up suffering painful and ignoble deaths, in some cases torn apart by angry mobs of those they have wronged. Less spectacularly, the majority end up alone, bored, and miserable because they have no higher purpose to sustain them. As they get older, it gets harder and harder to manipulate others because they can’t play the role of the poor vulnerable young person who just needs a break in life.

Psychopaths suffer many misfortunes of their own making. Their lives are punctuated by disasters, flights from responsibility, stints in jail, running from the law, injuries through carelessness and risk taking, and finally, debilitating illnesses caused by poor lifestyle choices and perhaps exacerbated by the chronic anger that results from frustrated desires.

Our early ancestors would not have survived the brutal conditions of cave-dwelling existence had they not cooperated and cared for one another. There is evidence that primitive humans took care of the ill and infirm among them. People looked after one another to increase their chances of survival, and they would not have done so if the majority had not been endowed with a sense of responsibility and the capacity for empathy. Those with a conscience would have taken better care of their children and other family members, and so those carrying similar genetic material would have been more likely to survive into adulthood and reproduce, thus carrying on the genetic lineage that favours a conscience.

The evolutionary roots of empathy can be seen in the behaviour of many animals, particularly among our close cousins, the bonobo monkeys. Primatologist Frans de Waal offers the touching story of a female bonobo who cared for an injured bird. The bird, having crash-landed in her enclosure, was unable to fly. The bonobo gently stretched out its wings and gave it a light toss. When this didn’t work, she carried it to the top of a tree and sent it sailing to the ground. The bird was still unable to fly, so the bonobo sat with it, comforting and protecting it until it had recovered sufficiently to fly out of the enclosure. Those who work with animals have witnessed many incidents suggestive of empathy, and among the more intelligent animals, these may cross species boundaries, indicating that compassion is part of the basic nature of most intelligent beings.

The existence of the emotions that lead to the development of a conscience—anxiety, empathy, shame, and guilt, increase the chances of both individual and group survival, as well as the survival of one’s offspring. Thus, having a conscience is useful. However, there are situations in which conscience can be overridden in all but the most psychologically strong individuals.

Under Certain Circumstances, Non-Psychopaths May Behave Like Psychopaths

There are certain circumstances in which non-psychopathic people will cause significant harm to innocent individuals. An experiment conducted by Stanley Milgram found that the majority of people were willing to give dangerous shocks to another person if an authoritative individual told them to do so. This gives insight as to why seemingly ordinary people commit wartime atrocities. Such studies indicate the dangers of training children to blindly obey authority figures rather than teaching them to critically analyze what is being asked of them. Appealing to patriotism is a tool used by many political leaders to ensure reflexive obedience to authority.

However, even in wartime, many people don’t want to kill. A study of World War II soldiers found that while most soldiers would fire their weapons if their commanders were present, firing dropped 15-20% as soon as leaders left the area. Soldiers who are forced to kill others often suffer post-traumatic stress disorder (PTSD) later on, while soldiers in dangerous areas who are not forced to kill are no more likely to acquire PTSD than those who never leave home in the first place. Only by viewing opponents as subhuman can the non-psychopathic person kill without remorse.

For more psychology articles, see the main Psychology page.


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    • Stout, M., PhD. (2005). The Sociopath Next Door. Crown Archetype.
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