Intermittent explosive disorder: Taming temper tantrums in the volatile, impulsive adult
More-inclusive diagnostic criteria acknowledge the true prevalence of this aggression disorder, and a new algorithm suggests a two-pronged treatment approach.
Axis II disorders. DSM-IV allows IED diagnosis in individuals with borderline or antisocial personality disorder, as long as these cluster B disorders do not better explain the aggressive behavior. How a clinician makes this distinction is not clear; in fact, most clinicians do not diagnose IED in patients with personality disorders, regardless of the clinical picture.
IED comorbidity with borderline or antisocial personality disorders varies with the sample. Persons with personality disorders who seek treatment of aggressive behavior are more likely to have comorbid IED (90%) than those not seeking treatment who are outpatients (50%) or in the community (25%).1,7
Individuals with personality disorders and IED score higher in aggression and lower in psychosocial function than do similar individuals without IED,7 indicating that the additional diagnosis is relevant.
Case report continued.
Mr. P’s outbursts have cost him several friendships, including romantic relationships. He has never advanced at work because he is seen as too volatile to supervise subordinates. Though some of Mr. P’s aggressive outbursts have occurred under the influence of alcohol, most are not related to alcohol or drug use. He has no medical problems and no other psychiatric history.
A full diagnostic evaluation uncovers a personality disorder, not otherwise specified (eight scattered traits from obsessive-compulsive personality disorder and from each of the cluster B personality disorders), and no Axis I condition other than intermittent explosive disorder.
PROBLEMS DEFINING IED
Intermittent explosive disorder is the only DSM diagnosis that applies to persons with histories of recurrent, problematic aggression not caused by another mental or physical disorder. Even so, little research on IED is available. DSM criteria for IED are poorly operationalized and have improved only modestly since the diagnosis was first included in DSM-III. In that revision, IED had four criteria.
“A” criteria specified recurrent outbursts of “seriously assaultive or destructive behavior,” but left unanswered important questions such as:
- What behavior crosses the threshold for seriously” assaultive or destructive?
- Does any physical assault qualify, or only those that cause physical injury (or stigmata)?
- How often or within what time must the behavior occur?
The phrase “recurrent acts of aggression” suggested that at least three acts of aggression were required to reach the threshold, but DSM-III provided no guidelines.
“B” criteria stated that the aggression should be out of proportion to the provocation. But how should one judge this criterion, when provocative stimuli sometimes are clearly sufficient to prompt a justifiably aggressive act?
“C” criteria excluded persons who are aggressive or impulsive between ill-defined “aggressive episodes.” This exclusion was especially limiting because individuals with recurrent, problematic, aggressive behaviors generally are impulsive and aggressive between more-severe outbursts. Excluding those who otherwise met diagnostic criteria for IED led to a spuriously low prevalence rate and limited the number of research subjects. DSM-IV eliminated this criterion but made no other notable changes in IED criteria.
“D” criteria in DSM-III and III-R further restricted the number of individuals who could meet this diagnosis:
- In DSM-III, antisocial personality disorder excluded the diagnosis of IED.
- In DSM-III-R, borderline personality disorder was added as an exclusionary factor.
Because of these restrictions, very few clinically valid cases of IED (individuals meeting A and B criteria) could receive an IED diagnosis.10
EVOLVING DIAGNOSTIC CRITERIA
By the early 1990s, DSM diagnostic criteria clearly severely restricted the study of recurrent, problematic aggression, even though research since DSM-III had greatly advanced our understanding of human aggression. For example, data linked impulsive aggression to deficits in central serotonergic function and suggested that agents that enhance serotonergic activity could modify this behavior.
Some investigators proposed research criteria for IED (IED-R) so that individuals with recurrent, problematic, impulsive aggression could be identified and studied. Research criteria first published in 19987 proposed six changes/clarifications in IED diagnostic criteria:
Lower-intensity aggression. The scope of aggressive behavior was expanded to include verbal and indirect physical aggression, provided that these behaviors are associated with distress and/or impairment. Data from double-blind, placebo-controlled trials indicated that these lower-intensity (although usually higher frequency) behaviors respond well to treatment with SSRIs.11,12
Impulsivity. The aggression was specified as impulsive. This change identified individuals with greater liability for deficits in central serotonergic function and excluded individuals with premeditated or criminal aggression.
A minimal frequency of aggression over time was proposed to make the IED diagnosis more reliable and to ensure that persons with only occasional impulsive aggressive outbursts (especially of low severity) were given this diagnosis.
Subjective distress (in the individual) and/or social or occupational dysfunction was proposed so that putatively aggressive individuals are not diagnosed for manifesting behaviors that are not functionally severe.
