Abstract
Psychopathy appears to be comprised of two broad dimensions: impulsivity/antisocial behavior and interpersonal detachment/callousness. This study examined the extent to which variance in these 2 psychopathy trait dimensions was associated with common or unique genetic, shared, and nonshared environmental factors in two independent samples of reared together 16-18-year-old male twins. One sample included 142 monozygotic (MZ) and 70 dizygotic (DZ) pairs; the other sample included 128 MZ and 58 DZ pairs. Boys completed the Minnesota Temperament Inventory (MTI), a 19-item measure that contains separate subscales: Antisocial and Detachment. Variance in the Antisocial and Detachment scales was associated with additive genetic factors and neither scale was associated with shared environmental factors. As expected, the bivariate biometric analysis suggested genetic influence on the covariance of the scales. The results are consistent with theoretical models of psychopathy that posit some independence in the etiology of the two major trait dimensions of psychopathy.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 633-645 |
| Number of pages | 13 |
| Journal | Journal of Abnormal Child Psychology |
| Volume | 31 |
| Issue number | 6 |
| DOIs | |
| State | Published - Dec 2003 |
Bibliographical note
Funding Information:Our expectations were supported by the results from the analysis of two independent twin samples. The sizable correlation (r D :74) between the genetic factors associated with individual differences in the Antisocial and Detachment scales coupled with the finding of common genetic variance in the two scales indicates that some set of genetic factors contributes to the expression of different features of psychopathy. Early biological models of psychopathy and other forms of disinhibited psychopathology implicated a disruption of a system in the brain composed of the medial septum, the hippocampus, and the orbitofrontal cortex (Gorenstein & Newman, 1980). Others have suggested that psychopathy stems from a weakness in a hypothesized behavioral inhibition system (BIS) that mediates responses in situations where negative consequences are expected (Fowles, 1988). Gray (1987) proposed the neural mechanism for the BIS, which includes the prefrontal cortex, hippocampal formation, and septal areas (including the medial septum). More recently, Blair and his colleagues (Blair, 1995; Blair & Coles, 2001; Blair, Morris, Frith, Perrett, & Dolan, 1999) have found support for the notion of distinct biological substrates for different patterns of aggression: the orbito-frontal circuitry is linked to reactive, impulsive, or hostile aggression, whereas, proactive, instrumental, or planful aggression is linked to amygdala dysfunction. This is of particular interest given that child psychopathy has been characterized by elevations in both reactive and proactive aggression (Frick & Ellis, 1999). The biological substrates of psychopathy are proposed to lie in certain brain structures in the frontal and temporal lobes. The present findings of common genetic influence on the two major trait dimensions of psychopathy are consistent with the notion of common biological substrates for impulsivity/antisocial behavior and emotional detachment. However, the present results indicated that only half of the genetic variance in emotional detachment could be attributed to genetic factors associated with impulsivity/ antisocial behavior, which is consistent with the idea that there may be some independence in the biological substrates underlying the two major trait dimensions of psychopathy.
Keywords
- Adolescent
- Genetic, twin
- Psychopathy