Twin studies, which are designed to discern between genetic and environmental effects, have reported significant genetic influences on antisocial behavior and conduct disorder.In the specific genes that may be involved, one gene that has seen particular interest in its correlation with antisocial behavior is the gene that encodes for monoamine oxidase A (MAO-A), an enzyme that breaks down monoamine neurotransmitters such as serotonin and norepinephrine. Various studies examining the genes relationship to behavior have suggested that variants of the gene that results in less MAO-A being produced, such as the 2R and 3R alleles of the promoter region, have associations with aggressive behavior in men. The association is also influenced by negative experience in early life, with children possessing a low-activity variant (MAOA-L) who experience such maltreatment being more likely to develop antisocial behavior than those with the high-activity variant (MAOA-H). Even when environmental interactions (e.g. emotional abuse) are controlled for, a small association between MAOA-L and aggressive and antisocial behavior remains.The gene that encodes for the serotonin transporter (SCL6A4), a gene that is heavily researched for its associations with other mental disorders, is another gene of interest in antisocial behavior and personality traits. Genetic associations studies have suggested that the short "S" allele is associated with impulsive antisocial behavior and ASPD in the inmate population. However, research into psychopathy find that the long "L" allele is associated with the Factor 1 traits of psychopathy, which describes its core affective (e.g. lack of empathy, fearlessness) and interpersonal (e.g. grandiosity, manipulativeness) personality disturbances.
It would later resurface as the name of a diagnosis in the ICD manual produced by the WHO, later spelled dissocial personality disorder and considered approximately equivalent to the ASPD diagnosis.The DSM-III in 1980 included the full term antisocial personality disorder and, as with other disorders, there was now a full checklist of symptoms focused on observable behaviors to enhance consistency in diagnosis between different psychiatrists (inter-rater reliability). The ASPD symptom list was based on the Research Diagnostic Criteria developed from the so-called Feighner Criteria from 1972, and in turn largely credited to influential research by sociologist Lee Robins published in 1966 as "Deviant Children Grown Up". However, Robins has previously clarified that while the new criteria of prior childhood conduct problems came from her work, she and co-researcher psychiatrist Patricia ONeal got the diagnostic criteria they used from Lees husband the psychiatrist Eli Robins, one of the authors of the Feighner criteria who had been using them as part of diagnostic interviews.The DSM-IV maintained the trend for behavioral antisocial symptoms while noting "This pattern has also been referred to as psychopathy, sociopathy, or dyssocial personality disorder" and re-including in the Associated Features text summary some of the underlying personality traits from the older diagnoses. The DSM-5 has the same diagnosis of antisocial personality disorder. The Pocket Guide to the DSM-5 Diagnostic Exam suggests that a person with ASPD may present "with psychopathic features" if he or she exhibits "a lack of anxiety or fear and a bold, efficacious interpersonal style".