Psychopathy may be an evolutionary adaptation rather than a mental disorder

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Historically, psychopathy has been conceptualized as a mental disorder, along with antisocial personality disorder. However, there is growing evidence that it is more the result of a process of natural selection, through an adaptive strategy. Canadian researchers have just presented the results of a meta-analysis of 16 studies which works in this direction: there would be no difference in the rates of non-right-handedness (an indicator of neurological disturbance) between psychopaths and non-psychopaths. However, the results should be qualified, because the meta-analysis has some limitations.

A psychopathic personality is notably characterized by antisocial, impulsive, manipulative and insensitive behavior. Several of the criteria defined in the Diagnostic and Statistical Manual of Mental Disorders (DSM) lead to the conclusion of the existence of an antisocial personality disorder (APD), also called psychopathy.

However, the two syndromes can be distinguished, with some claiming that APD represents the lower or less severe end of the continuum of psychopathy. ” A diagnosis of APD is strongly linked to the behavioral/antisocial dimension of psychopathy, but it is less strongly linked to the interpersonal/affective traits of psychopathy, which are often considered to be the hallmarks of this syndrome. write Lesleigh E. Pullman and her colleagues in their study.

Psychopathy has long been considered a mental disorder, although there are another perspective, focused on evolution: it would rather be a strategy of social exploitation of life history maintained by frequency-dependent negative selection “, report the Canadian researchers. From this perspective, “risk-taking, opportunism, and insensitive behavior,” characteristic of psychopaths, would have increased reproductive success in ancestral environments, under certain conditions (psychopathic individuals might have exploited the trust of others to improve their chances of reproduction). According to the authors, these psychopathic traits would have been favored by selection over successive generations.

Estudy the non-droitisation to explain the origin of psychopathy

The meta-analysis of 16 studies (between 1985 and 2017) aims to verify this hypothesis, using the “non-droitisation” (left-handedness, mixed or ambidexterity, measured by self-reported hand preference or hand preference during writing) as an indicator of neurological disturbance. Indeed, compared to healthy control groups, there are more non-right-handed people in people with schizophrenia and depression. The same is true for low birth weight and complications, prenatal stress, and prenatal hormone exposure, suggesting that non-straightening may be related to impaired pre- and perinatal brain development.

Furthermore, even if the origin of mental disorders is not entirely clear, it is probably a disturbance of neurological development. Psychopaths should therefore be predominantly non-right-handed if their problem stemmed primarily from a mental disorder, according to the researchers. Otherwise, they are considered neurologically healthy and the adaptive strategy perspective is preferred.

The researchers examined the association between psychopathy and being right-handed for a total of 1818 participants. Ultimately, there was no difference in rates of non-right-handedness between participants with high and low levels of psychopathy, and between psychopathic and non-psychopathic patients. In contrast, the authors noted a tendency for offenders scoring higher in the behavioral dimension of psychopathy to be more non-right-handed; the reverse is true for offenders scoring higher on the interpersonal/affective dimension of psychopathy.

The behavioral dimension of psychopathy can be conceptually closer to [trouble de la personnalité antisociale] and persistent delinquency throughout life “, report the researchers. ” Thus, our results do not support the mental disorder model and partially support the adaptive strategy model. “.

Limitations of the meta-analysis

The results on the origins of psychopathy remain to be nuanced, because there are many limitations presented by the researchers themselves. First, a small number of primary studies have examined the relationship between psychopathy and nonrighting, and thus the statistical power was relatively low. Then, the fact that psychopaths may have other mental illnesses was not taken into account in the work, which could have led to other results.

Finally, you should know that the adaptive model of psychopathy concerns men. However, the samples of participants were partially or totally composed of women, which can also disturb the results.

Source : Evolutionary Psychology

Psychopathy may be an evolutionary adaptation rather than a mental disorder