A study from 2004 by Viding, Blair, Moffitt and Plomin showed strong evidence that psychopathy is genetic.
“Background: Individuals with early warning signs of life-long psychopathy, callous-unemotional traits (CU) and high levels of antisocial behaviour (AB) can be identified in childhood. We report here the first twin study of high levels of psychopathic tendencies in young children.
Methods: At the end of the first school year, teachers provided ratings of CU and AB for 3687 twin pairs from the Twins Early Development Study (TEDS). For the analyses of extreme CU, we selected same-sex twin pairs where at least one twin scored 1.3 or more standard deviations above the mean on the CU scale (612 probands, 459 twin pairs). For the analysis of extreme AB, we selected same-sex twin pairs where at least one twin scored 1.3 or more standard deviations above the mean on AB scale (444 probands, 364 twin pairs). Furthermore, the extreme AB sample was divided into those who were also extreme on CU (children with psychopathic tendencies; 234 probands, 187 twin pairs) and those who did not score in the extreme for CU (children without psychopathic tendencies; 210 probands, 177 twin pairs).
Results: DeFries–Fulker extremes analysis indicated that exhibiting high levels of CU is under strong genetic influence. Furthermore, separating children with AB into those with high and low levels of CU showed striking results: AB in children with high levels of CU is under extremely strong genetic influence and no influence of shared environment, whereas AB in children with low levels of CU shows moderate genetic and shared environmental influence.
Conclusions: The remarkably high heritability for CU, and for AB children with CU, suggests that molecular genetic research on antisocial behaviour should focus on the CU core of psychopathy. Our findings also raise questions for public policy on interventions for antisocial behaviour.”
Evidence for substantial genetic risk for psychopathy in 7-year-olds Here
Also of interest from 2004, Annotation: Understanding the development of psychopathy. Here
Viding et al. in 2007, came to the following conclusion;
“A previous finding from our group indicated that teacher-rated antisocial behaviour (AB) among 7-year-olds is particularly heritable in the presence of callous-unemotional (CU) traits. Using a sample of 1865 same-sex twin pairs, we employed DeFries-Fulker extremes analysis to investigate whether teacher-rated AB with/without CU traits also shows aetiological differences among 9-year-olds. Furthermore, we assessed whether the differences in the magnitude of heritability would be evident even when hyperactive symptoms were controlled for in the statistical analysis. AB among 9-year-olds was more heritable with than without concomitant CU. The heritability difference was even more pronounced in magnitude when hyperactive symptoms were controlled. CU traits thus appear to index one valid way of sub-typing children with early-onset AB.” Heritability of antisocial behaviour at 9: do callous-unemotional traits matter? Here
Another study of interest from 2007 indicated that early warning signs can be detected at age 3. Early temperamental and psychophysiological precursors of adult psychopathic personality. By; Glenn et al. Here
Also of interest from 2007; A structural neural deficit in adolescents with conduct disorder and its association with lack of empathy. Philipp Sterzer et al. Here
Furthermore, a study from 2008, showed “stability of psychopathic personality between mid- and late adolescence”, Genetic effects explain the stability of psychopathic personality from mid- to late adolescence. Here
In 2009 came yet other studies of interest, Size matters: Increased grey matter in boys with conduct problems and callous–unemotional traits. Here and The contribution of callous-unemotional traits and conduct problems to bullying in early adolescence, which stated that, “This study highlights the importance of viewing CU traits and conduct problems, not only as related phenomena, but also as distinct entities in mediating the underlying susceptibility of children to bully others directly. Furthermore, a combination of these traits appears to be a particularly potent risk factor for both direct and indirect bullying. Implications for intervention are discussed, in particular the concern that lack of empathy and insensitivity to punishment in those with CU traits may also make them particularly resistant to current forms of bullying intervention.” Study found Here
Yet another study from 2009, Genetic variation in neuregulin1 is associated with differences in prefrontal engagement in children. Here
In July 2010 Viding et al. study found single-nucleotide polymorphisms (SNPs) “that are potentially associated with psychopathic tendencies, which we believe warrant verification and replication in large independent and clinical samples.” In search of genes associated with risk for psychopathic tendencies in children: a two-stage genome-wide association study of pooled DNA. More Here
Another study from 2010 came to the following conclusion, that; “Poor fear conditioning at age 3 predisposes to crime at age 23. Poor fear conditioning early in life implicates amygdala and ventral prefrontal cortex dysfunction and a lack of fear of socializing punishments in children who grow up to become criminals. These findings are consistent with a neurodevelopmental contribution to crime causation.” Association of Poor Childhood Fear Conditioning and Adult Crime. Here
Also of great interest;
A longitudinal twin study of the direction of effects between psychopathic personality and antisocial behaviour. By; Mats Forsman, Paul Lichtenstein, Henrik Andershed and Henrik Larsson. Journal of Child Psychology and Psychiatry, Volume 51, Issue 1, pages 39–47, January 2010. Here and,
Reduced electrodermal fear conditioning from ages 3 to 8 years is associated with aggressive behavior at age 8 years. By; Yu Gao, Adrian Raine, Peter H. Venables, Michael E. Dawson, Sarnoff A. Mednick. Journal of Child Psychology and Psychiatry, Volume 51 Issue 5, Pages 550 – 558. (May 2010) Here
As is, Heritable Variations in Gray Matter Concentration as a Potential Endophenotype for Psychopathic Traits. (April 2010) Here
Finally, two more studies of great interest, one concerning CU traits; Facial Expression Recognition, Fear Conditioning, and Startle Modulation in Female Subjects with Conduct Disorder. Biological Psychiatry, In Press (Online May 2010) Here and the other concerning ODD,
Impaired Decision Making in Oppositional Defiant Disorder Related to Altered Psychophysiological Responses to Reinforcement. (Online April 2010) Here
As well as; Heritable Variations in Gray Matter Concentration as a Potential Endophenotype for Psychopathic Traits (2010) Here
Young “bullies” cause great suffering and even death wherever they may be, Bullycide: Bullied to Death Memorial (video) Here , Bullycide in America Here Bullycide – Death at playtime Here Bullying, should be noted, is the same all over the world as it involves the same neurodevelopmental damage. It should also be noted that “bullies” enjoy hurting others, as this makes the the feel “powerful”. Bullies may enjoy seeing others in pain: Brain scans show disruption in natural empathetic response. (2008) “Unusually aggressive youth may actually enjoy inflicting pain on others, research using brain scans at the University of Chicago shows.” More Here Anyone who has ever dealt with a “bully” will tell you that “may”, is an understatement.
So what happens when the “bully” grows up? Answer: The individual becomes even more dangerous! Absolute power and control over others are core traits of psychopathy and without a conscience and no empathyand he/she will do anything to “win”, even kill. The “big bullies” we need to worry about are of course, the “bullies in power” which among other things, are showering us with neurotoxins and other unpleasant things from above, see “Chemtrails”, one of many videos, Here which of course is causing great damage to humans and the environment, What in the World Are They Spraying? Part I (March 24, 2010) Here, part II Here GMO, very harmful as it causes damage to the internal organs, A Comparison of the Effects of Three GM Corn Varieties on Mammalian Health. Here It will most likely also render the third generation sterile, more Here and Here and Antibiotic resistance genes from GM plants “unlikely” to transfer to bacteria Here How about the toxic “vaccines” they tried to push on an unsuspecting population in 2009, the big “Swine flu scare” ?
To get some more insight; Psychopaths’ Brains Wired to Seek Rewards, No Matter the Consequences (Mar. 15, 2010) Here and the study, Study Mesolimbic dopamine reward system hypersensitivity in individuals with psychopathic traits. Here Last but not least, Dr. Simon’s recent post, Confessions of a Covert-Aggressive Personality, is also a must to read Here