I came across a really intersting meta-analysis which suggests that psychopathy may be an adaptation, rather than a mental disorder.
The meta-analysis includes 16 studies that investigated the association between psychopathy and handedness in various populations.
Although psychopathy is already widespread as a mental disorder among the scientific community, “an alternative, evolution-minded perspective has been proposed: that psychopathy is instead a life history strategy of social exploitation maintained by negative frequency-dependent selection,” write Lesleigh E. Pullman and colleagues.
According to the evolutionary view, the risk taking, opportunistic, and callous behavior exhibited by psychopaths would have increased reproductive success in ancestral environments under certain conditions (such as a high ratio of cooperators to psychopaths). Consequently, these traits would have been favored by selection over successive generations.
This study concerns a meta-analysis of one testable hypothesis related to the debate concerning psychopathy as a mental disorder versus an alternative life history strategy: the extent to which psychopathic individuals are more or less likely to exhibit signs of neurodevelopmental perturbations compared to nonpsychopathic individuals. Neurodevelopmental perturbations are difficult to assess directly, but can be measured indirectly. Nonright-handedness (left-handedness, mixed-handedness) is a sign of neurodevelopmental problems (Brandler & Paracchini, 2014; Carlsson et al., 1992; Oh et al., 2009; Orsini & Satz, 1986; for a review, see Schmitz et al., 2017; c.f. Bishop, 1990).
Therefore, this meta-analysis focuses on an accessible proxy for neurodevelopmental perturbations: the extent to which psychopaths are more likely to display nonright-handedness compared to nonpsychopathic individuals.
The results indicate that Pullman and colleagues did not find support for the mental disorder model of psychopathy, with the meta-analysis providing partial support for the adaptive life history model of psychopathy.
-There were no differences in the rate of non right-handedness between community participants scoring high (vs. low) in psychopathy.
-And while there was no difference in rates of non right-handedness between psychopathic (vs. non psychopathic) offenders, there was a tendency for those with higher scores on the interpersonal/affective dimension of psychopathy to have lower rates of non right-handedness, while those scoring higher on the behavioural dimension had higher rates of non right-handedness. -The behavioural dimension of psychopathy may be “conceptually more similar to [antisocial personality disorder] and life-course-persistent offending.”
-Lastly, there were no differences in rates of non right-handedness between psychopathic (vs. non psychopathic) mental health patients.
The study, “Is Psychopathy a Mental Disorder or an Adaptation? Evidence From a Meta-Analysis of the Association Between Psychopathy and Handedness”, was authored by Lesleigh E. Pullman, Nabhan Refaie, Martin L. Lalumière, and DB Krupp.