<unk>  disorders are seen to be caused by a combination and interaction of genetic and environmental influences. Genetically, it is the intrinsic temperamental tendencies as determined by their genetically influenced physiology, and environmentally, it is the social and cultural experiences of a person in childhood and adolescence encompassing their family dynamics, peer influences, and social values. People with an<unk>  or alcoholic parent are considered to be at higher risk. Fire-setting, and cruelty to animals during childhood are also linked to the development of<unk><unk> . The condition is more common in males than in females, and among incarcerated populations. Genetic Research into genetic associations in<unk>  suggests that<unk>  has some or even a strong genetic basis. Prevalence of<unk>  is higher in people related to someone afflicted by the disorder. Twin studies, which are designed to discern between genetic and environmental effects, have reported significant genetic influences on<unk>  behavior and conduct disorder. In the specific genes that may be involved, one gene that has seen particular interest in its correlation with<unk>  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<unk>  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<unk>  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<unk>  behavior and<unk>  traits. Genetic associations studies have suggested that the short "S" allele is associated with impulsive<unk>  behavior and<unk>  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)<unk>  disturbances. 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<unk>  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<unk>  is comorbid. Furthermore, the study found that those who carry 4 mutations on chromosome 6 are 50 percent more likely to develop<unk>  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<unk> . 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<unk>  is serotonin, also known as 5HT. A meta-analysis of 20 studies found significantly lower 5-HIAA levels (indicating lower serotonin levels), especially in those who are younger than 30 years of age. While it has been shown that lower levels of serotonin may be associated with<unk> , there has also been evidence that decreased serotonin function is highly correlated with impulsiveness and aggression across a number of different experimental paradigms. Impulsivity is not only linked with irregularities in 5HT metabolism, but may be the most essential psychopathological<unk> ect linked with such dysfunction. Correspondingly, the DSM classifies "impulsivity or failure to plan ahead" and "irritability and aggressiveness" as two of seven sub-criteria in category A of the diagnostic criteria of<unk> . Some studies have found a relationship between monoamine oxidase A and<unk>  behavior, including conduct disorder and symptoms of adult<unk> , in maltreated children. Neurological<unk>  behavior may be related to head trauma.<unk>  behavior is associated with decreased grey matter in the right lentiform nucleus, left insula, and frontopolar cortex. Increased volumes have been observed in the right fusiform gyrus, inferior parietal cortex, right cingulate gyrus, and post central cortex. Intellectual and cognitive ability is often found to be impaired or reduced in the<unk>  population. Contrary to stereotypes in popular culture of the "psychopathic genius",<unk>  is associated with both reduced overall intelligence and specific reductions in individual<unk> ects of cognitive ability. These deficits also occur in general-population samples of people with<unk>  traits and in children with the precursors to<unk> . People that exhibit<unk>  behavior tend to demonstrate decreased activity in the prefrontal cortex. The association is more apparent in functional neuroimaging as opposed to structural neuroimaging. The prefrontal cortex is involved in many executive functions, including behavior inhibitions, planning ahead, determining consequences of action, and differentiating between right and wrong. However, some investigators have questioned whether the reduced volume in prefrontal regions is associated with<unk> , or whether they result from co-morbid disorders, such as substance use disorder or childhood maltreatment. Moreover, it remains an open question whether the relationship is causal, i.e., whether the anatomical abnormality causes the psychological and behavioral abnormality, or vice versa. Cavum septi pellucidi (CSP) is a marker for limbic neural maldevelopment, and its presence has been loosely associated with certain mental disorders, such as schizophrenia and post-traumatic stress disorder. One study found that those with CSP had significantly higher levels of<unk><unk> , psychopathy, arrests and convictions compared with controls. Environmental Family environment Many studies suggest that the social and home environment has contributed to the development of<unk>  behavior. The parents of these children have been shown to display<unk>  behavior, which could be adopted by their children. A lack of parental stimulation and affection during early development leads to high levels of cortisol with the absence of balancing hormones such as oxytocin which disrupts and overloads the child's stress response systems, which is thought to lead to underdevelopment of the child's brain that deals with emotion, empathy and ability to connect to other humans on an emotional level. According to Dr. Bruce Perry in his book The Boy Who Was Raised as a Dog, "the infant's developing brain needs patterned, repetitive stimuli to develop properly. Spastic, unpredictable relief from fear, loneliness, discomfort, and hunger keeps a baby's stress system on high alert. An environment of intermittent care punctuated by total abandonment may be the worst of all worlds for a child." Cultural influences The sociocultural perspective of clinical psychology views disorders as influenced by cultural<unk> ects; since cultural norms differ significantly, mental disorders such as<unk>  are viewed differently. Robert D. Hare has suggested that the rise in<unk>  that has been reported in the United States may be linked to changes in cultural mores, the latter serving to validate the behavioral tendencies of many individuals with<unk> . While the rise reported may be in part merely a byproduct of the widening use (and abuse) of diagnostic techniques, given Eric Berne's division between individuals with active and latent<unk>  – the latter keeping themselves in check by attachment to an external source of control like the law, traditional standards, or religion – it has been suggested that the erosion of collective standards may indeed serve to release the individual with latent<unk>  from their previously prosocial behavior. There is also a continuous debate as to the extent to which the legal system should be involved in the identification and admittance of patients with preliminary symptoms of<unk> . Controversial clinical psychiatrist Pierre-Édouard Carbonneau suggested that the problem with legal forced admittance is the rate of failure when diagnosing<unk> . He contends that the possibility of diagnosing and coercing a patient into prescribing medication to someone without<unk> , but is diagnosed with<unk> , could be potentially disastrous. But the possibility of not diagnosing<unk>  and seeing a patient go untreated because of a lack of sufficient evidence of cultural or environmental influences is something a psychiatrist must ignore; and in his words, "play it safe". ICD-10 The WHO's International Statistical Classification of Diseases and Related Health Problems, tenth edition (ICD-10), has a diagnosis called dissocial<unk>  disorder (): :It is characterized by at least 3 of the following: :# Callous unconcern for the feelings of others; :# Gross and persistent attitude of irresponsibility and disregard for social norms, rules, and obligations; :# Incapacity to maintain enduring relationships, though having no difficulty in establishing them; :# Very low tolerance to frustration and a
Antisocial personality disorder
Sadistic personality disorder
Obsessive–compulsive personality disorder
Psychopathy
Haltlose personality disorder
Histrionic personality disorder
Self-defeating personality disorder
Organic personality disorder