The category was described as more specific and limited than the existing concepts of "constitutional psychopathic state" or "psychopathic personality" which had had a very broad meaning; the narrower definition was in line with criteria advanced by Hervey M. Cleckley from 1941, while the term sociopathic had been advanced by George Partridge in 1928 when studying the early environmental influence on psychopaths. Partridge discovered the correlation between antisocial psychopathic disorder and parental rejection experienced in early childhood.The DSM-II in 1968 rearranged the categories and "antisocial personality" was now listed as one of ten personality disorders but still described similarly, to be applied to individuals who are: "basically unsocialized", in repeated conflicts with society, incapable of significant loyalty, selfish, irresponsible, unable to feel guilt or learn from prior experiences, and who tend to blame others and rationalize. The manual preface contains "special instructions" including "Antisocial personality should always be specified as mild, moderate, or severe." The DSM-II warned that a history of legal or social offenses was not by itself enough to justify the diagnosis, and that a "group delinquent reaction" of childhood or adolescence or "social maladjustment without manifest psychiatric disorder" should be ruled out first. The dyssocial personality type was relegated in the DSM-II to "dyssocial behavior" for individuals who are predatory and follow more or less criminal pursuits, such as racketeers, dishonest gamblers, prostitutes, and dope peddlers. (DSM-I classified this condition as sociopathic personality disorder, dyssocial type).
This is suggestive of two different forms, one associated more with impulsive behavior and emotional dysregulation, and the other with predatory aggression and affective disturbance, of the disorder.Various other gene candidates for ASPD have been identified by a genome-wide association study published in 2016. Several of these gene candidates are shared with attention-deficit hyperactivity disorder, with which ASPD is comorbid. Furthermore, the study found that those who carry four mutations on chromosome 6 are 50 percent more likely to develop antisocial personality disorder than those who do not. Physiological
Hormones and neurotransmitters
Traumatic events can lead to a disruption of the standard development of the central nervous system, which can generate a release of hormones that can change normal patterns of development. Aggressiveness and impulsivity are among the possible symptoms of ASPD. Testosterone is a hormone that plays an important role in aggressiveness in the brain. For instance, criminals who have committed violent crimes tend to have higher levels of testosterone than the average person. The effect of testosterone is counteracted by cortisol which facilitates the cognitive control of impulsive tendencies.One of the neurotransmitters that has been discussed in individuals with ASPD is serotonin, also known as 5HT.