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Intermittent Explosive Disorder

Intermittent Explosive Disorder

Intermittent Explosive Disorder

Intermittent Explosive Disorder (IED) is characterized by extreme expressions of anger, often to the point of uncontrollable rage, that are disproportionate to the situation at hand.

It is currently categorized as an Impulse Control Disorder.

Impulsive aggression is unpremeditated, and is defined by a disproportionate reaction to any provocation, real or perceived.  Some individuals have reported affective changes prior to an outburst such as tension, mood changes, energy changes, etc.

Individuals diagnosed with IED report their outbursts were brief (lasting less than an hour), with a variety of bodily symptoms (sweating, chest tightness, twitching, palpitations).

Violent acts may be accompanied by a sensation of relief, and in some cases, pleasure, then remorse after the fact.

Criteria:

  • Occurrence of discrete episodes of failure to resist aggressive impulses that result in violent assault or destruction of property
  • Degree of aggressiveness expressed during an episode is grossly disproportionate to provocation or precipitating psychosocial stressor
  • Diagnosis is made when other mental disorders that may cause violent outbursts (e.g., antisocial personality disorder, borderline personality disorder, oppositional defiant disorder, etc.) have been ruled out.

In other words:

  • Several episodes of impulsive behavior that result in serious damage to either persons or property
    • The degree of the aggressiveness is grossly disproportionate to the circumstances or provocation
      • The episodic violence cannot be better accounted for by another mental or physical medical condition.

Findings suggest that IED may result from abnormalities in the areas of the brain that regulate behavioral arousal and inhibition.  Indicating that impulsive aggression is related to abnormal brain mechanisms in a system that inhibits motor (muscular movement) activity, called the serotoninergic system.  This system is directed by a neurotransmitter called serotonin, which regulates behavioral inhibition (control of behavior).  

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.

Impulsive behavior, and especially impulsive violence predisposition has been correlated to a low brain serotonin turnover rate, indicated by a low concentration of 5-Hydroxyindoleacetic acid (5-HIAA) in the cerebrospinal fluid (CSF).  This substrate appears to act on the suprachiasmatic nucleus in the hypothalamus, which is the target for serotonergic output from the dorsal and median raphe nuclei playing a role in maintaining the circadian rhythmand regulation of blood sugar.  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.  

Studies using positron emission tomography (PET) scanning have found lower levels of brain glucose (sugar) metabolism in patients who act in impulsively aggressive ways.

Other traits that correlate with IED are low vagal tone and increased insulin secretion.  

Some studies have correlated IED with abnormalities on both sides of the front portion of the brain.  These localized areas in the front of the brain appear to be involved in information processing and controlling movement, both of which are unbalanced in persons diagnosed with IED.  

IED may also be associated with lesions in the prefrontal cortex, with damage to these areas, including the amygdala, increasing the incidence of impulsive and aggressive behavior and the inability to predict the outcomes of an individual’s 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.

Quoted from Sources:
wikipedia.org – Intermittent Explosive Disorder
minddisorders.com – Intermittent Explosive Disorder

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