Intermittent explosive disorder (IED) is a disorder characterized by impulsive acts of aggression, as contrasted with planned violent or aggressive acts. The aggressive episodes may take the form of "spells" or "attacks," with symptoms beginning minutes to hours before the actual acting-out. The Diagnostic and Statistical Manual of Mental Disorders, fourth edition, text revision (also known as DSM-IV-TR) is the basic reference work consulted by mental health professionals in determining the diagnosis of a mental disorder. DSM-IV-TR classifies IED under the general heading of "Impulse-Control Disorders Not Elsewhere Classified." Other names for IED include rage attacks, anger attacks, and episodic dyscontrol.
Description
Intermittent explosive disorder was originally described by the eminent French psychiatrist Esquirol as a "partial insanity" related to senseless impulsive acts. Esquirol termed this disorder monomanies instinctives, or instinctual monomanias. These apparently unmotivated acts were thought to result from instinctual or involuntary impulses, or from impulses related to ideological obsessions.
People with intermittent explosive disorder have a problem with controlling their temper. In addition, their violent behavior is out of proportion to the incident or event that triggered the outburst. Impulsive acts of aggression, however, are not unique to intermittent explosive disorder. Impulsive aggression can be present in many psychological and nonpsychological disorders. The diagnosis of intermittent explosive disorder (IED) is essentially a diagnosis of exclusion, which means that it is given only after other disorders have been ruled out as causes of impulsive aggression.
Patients diagnosed with IED usually feel a sense of arousal or tension before an outburst, and relief of tension after the aggressive act. Patients with IED believe that their aggressive behaviors are justified; however, they feel genuinely upset, regretful, remorseful, bewildered or embarrassed by their impulsive and aggressive behavior.
Causes
Recent findings suggest that IED may result from abnormalities in the areas of the brain that regulate behavioral arousal and inhibition. Research indicates 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). 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. Studies using positron emission tomography (PET) scanning have found lower levels of brain glucose (sugar) metabolism in patients who act in impulsively aggressive ways.
Another study based on data from electroencephalograms (EEGs) of 326 children and adolescents treated in a psychiatric clinic found that 46% of the youths who manifested explosive behavior had unusual high-amplitude brain wave forms. The researchers concluded that a significant subgroup of people with IED may be predisposed to explosive behavior by an inborn characteristic of their central nervous system. In sum, there is a substantial amount of convincing evidence that IED has biological causes, at least in some people diagnosed with the disorder.
Other clinicians attribute IED to cognitive distortions. According to cognitive therapists, persons with IED have a set of strongly negative beliefs about other people, often resulting from harsh punishments inflicted by the parents. The child grows up believing that others "have it in for him" and that violence is the best way to restore damaged self-esteem. He or she may also have observed one or both parents, older siblings, or other relatives acting out in explosively violent ways. In short, people who develop IED have learned, usually in their family of origin, to believe that certain acts or attitudes on the part of other people "justify" aggressive attacks on them.
Although gender roles are not a "cause" of IED to the same extent as biological and familial factors, they are regarded by some researchers as helping to explain why most people diagnosed with IED are males. According to this theory, men have greater permission from society to act violently and impulsively than women do. They therefore have less reason to control their aggressive impulses. Women who act explosively, on the other hand, would be considered unfeminine as well as unfriendly or dangerous.
Symptoms
IED is characterized by violent behaviors that are impulsive as well as assaultive. One example involved a man who felt insulted by another customer in a neighborhood bar during a conversation that had lasted for several minutes. Instead of finding out whether the other customer intended his remark to be insulting, or answering the "insult" verbally, the man impulsively punched the other customer in the mouth. Within a few minutes, however, he felt ashamed of his violent act. As this example indicates, the urge to commit the impulsive aggressive act may occur from minutes to hours before the "acting out" and is characterized by the buildup of tension. After the outburst, the IED patient experiences a sense of relief from the tension. While many patients with IED blame someone else for causing their violent outbursts, they also express remorse and guilt for their actions.
Demographics
IED is apparently a rare disorder. Most studies, however, indicate that it occurs more frequently in males. The most common age of onset is the period from late childhood through the early 20s. The onset of the disorder is frequently abrupt, with no warning period. Patients with IED are often diagnosed with at least one other disorder—particularly personality disorders, substance abuse (especially alcohol abuse) disorders, and neurological disorders.
Diagnosis
As mentioned, IED is essentially a diagnosis of exclusion. Patients who are eventually diagnosed with IED may come to the attention of a psychiatrist or other
mental health professional by several different routes. Some patients with IED, often adult males who have assaulted their wives and are trying to save their marriages, are aware that their outbursts are not normal and seek treatment to control them. Younger males with IED are more likely to be referred for diagnosis and treatment by school authorities or the juvenile justice system, or brought to the doctor by concerned parents.
A psychiatrist who is evaluating a patient for IED would first take a complete medical and psychiatric history. Depending on the contents of the patient's history, the doctor would give the patient a physical examination to rule out head trauma, epilepsy, and other general medical conditions that may cause violent behavior. If the patient appears to be intoxicated by a drug of abuse or suffering symptoms of withdrawal, the doctor may order a toxicology screen of the patient's blood or urine. Specific substances that are known to be associated with violent outbursts include phencyclidine (PCP or "angel dust"), alcohol, and cocaine. The doctor will also give the patient a mental status examination and a test to screen for neurological damage. If necessary, a neurologist may be consulted and imaging studies performed of the patient's brain.
If the physical findings and laboratory test results are normal, the doctor may evaluate the patient for personality disorders, usually by administering diagnostic questionnaires. The patient may be given a diagnosis of antisocial or borderline personality disorder in addition to a diagnosis of IED.
In some cases the doctor may need to rule out malingering, particularly if the patient has been referred for evaluation by a court order and is trying to evade legal responsibility for his behavior.
Treatments
Some adult patients with IED appear to benefit from cognitive therapy. A team of researchers at the University of Pennsylvania found that cognitive approaches that challenged the patients' negative views of the world and of other people was effective in reducing the intensity as well as the frequency of violent episodes. With regard to gender roles, many of the men reported that they were helped by rethinking "manliness" in terms of self-control rather than as something to be "proved" by hitting someone else or damaging property.
Several medications have been used for treating IED. These include carbamazepine (Tegretol), an antiseizure medication; propranolol (Inderal), a heart medication that controls blood pressure and irregular heart rhythms; and lithium, a drug used to treat bipolar type II manic-depression disorder. The success of treatment with lithium and other mood-stabilizing medications is consistent with findings that patients with IED have a high lifetime rate of bipolar disorder.
Prognosis
Little research has been done on patients who meet DSM-IV-TR criteria for IED, although one study did find that such patients have a high lifetime rate of comorbid (co-occurring) bipolar disorder. In some people, IED decreases in severity or resolves completely as the person grows older. In others, the disorder appears to be chronic.
Prevention
As of 2002, preventive strategies include educating young people in parenting skills, and teaching children skills related to self-control. Recent studies summarized by an article in a professional journal of psychiatry indicate that self-control can be practiced like many other skills, and that people can improve their present level of self-control with appropriate coaching and practice.
Baumeister, Roy F., PhD. Chapter 8, "Crossing the Line: How Evil Starts." In Evil: Inside Human Violence and Cruelty. New York: W. H. Freeman and Company, 1999.
Beck, Aaron T., M.D. Prisoners of Hate: The Cognitive Basis of Anger, Hostility, and Violence. New York: HarperCollins, 1999.
Tasman, Allan, and others, eds. Psychiatry. 1st edition. Philadelphia: W. B. Saunders Company. 1997: 1249-1258.
PERIODICALS
Bars, Donald R., and others. "Use of Visual Evoked-Potential Studies and EEG Data to Classify Aggressive, Explosive Behavior of Youths." Psychiatric Services 52 (January 2001): 81-86.
McElroy, Susan L. "Recognition and Treatment of DSM-IV Intermittent Explosive Disorder." Journal of Clinical Psychiatry 60 (1999) [suppl. 15]: 12-16.
Strayhorn, Joseph M., Jr. "Self-Control: Theory and Research." Journal of the American Academy of Child and Adolescent Psychiatry 41 (January 2002): 7-16.
