A tendency towards low 5-HIAA may be hereditary. A putative hereditary component to low CSF 5-HIAA and concordantly possibly to impulsive violence has been proposed. Other traits that correlate with IED are low vagal tone and increased insulin secretion. A suggested explanation for IED is a polymorphism of the gene for tryptophan hydroxylase, which produces a serotonin precursor; this genotype is found more commonly in individuals with impulsive behavior.IED may also be associated with damage or lesions in the prefrontal cortex, with damage to these areas, including the amygdala and hippocampus, increasing the incidences of impulsive and aggressive behavior and the inability to predict the outcomes of an individuals own actions. Lesions in these areas are also associated with improper blood sugar control, leading to decreased brain function in these areas, which are associated with planning and decision making. A national sample in the United States estimated that 16 million Americans may fit the criteria for IED.
This led some researchers to adopt alternate criteria set with which to conduct research, known as the IED-IR (Integrated Research). The severity and frequency of aggressive behavior required for the diagnosis were clearly operationalized, the aggressive acts were required to be impulsive in nature, subjective distress was required to precede the explosive outbursts, and the criteria allowed for comorbid diagnoses with borderline personality disorder and antisocial personality disorder. These research criteria became the basis for the DSM-5 diagnosis. In the current version of the DSM (DSM-5), the disorder appears under the "Disruptive, Impulse-Control, and Conduct Disorders" category. In the DSM-IV, physical aggression was required to meet the criteria for the disorder, but these criteria were modified in the DSM-5 to include verbal aggression and non-destructive/noninjurious physical aggression. The listing was also updated to specify frequency criteria. Further, aggressive outbursts are now required to be impulsive in nature and must cause marked distress, impairment, or negative consequences for the individual. Individuals must be at least six years old to receive the diagnosis. The text also clarified the disorders relationship to other disorders such as ADHD and disruptive mood dysregulation disorder. See also
Episodic dyscontrol syndrome
Passive–aggressive personality disorder

References


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