Intermittent Explosive Disorder

Descriptive Characteristics and Phenomenology

File photo. [Credit: HealthlineOpens in new window] Individuals with intermittent explosive disorder recurrently fail to resist acting on their impulsive or aggressive behaviors and will, after the precipitating event or just unprovoked, destroy property or assault people.

The symptoms, which patients may describe as spells or attacks, appear within minutes or hours and, regardless of duration, remit spontaneously and quickly. After each episode, patients usually show genuine regret or self-reproach, and signs of generalized impulsivity or aggressiveness are absent between episodes.

People with IED describe their aggressive episodes as brief, explosive, uncontrollable, and unpremeditated, and typically provoked by minor events. They may experience changes in mood, awareness, and autonomic arousal before the outburst.

Before making the diagnosis, IED needs to be distinguished from Cluster B personality disorders associated with anger outbursts (antisocial and borderline personality disorders), neurocognitive disorders characterized by verbal or physical outbursts, substance abuse and intoxication causing behavioral disinhibition, and the childhood-onset disorders: disruptive mood dysregulation disorder, autism spectrum disorder, attention-deficit/hyperactivity disorder, ODD, and conduct disorder.

In the case of the childhood-onset disorders, the additional diagnosis of IED may be warranted when outbursts are deemed in excess of those usually seen in the disorders and warrant independent clinical attention.

Epidemiology

Intermittent explosive disorder is underreported. The disorder appears to be more common in men than in women. The men are likely to be found in correctional institutions and the women in psychiatric facilities.

In one study, about 2 percent of all persons admitted to a university hospital psychiatric service had disorders that were diagnosed as intermittent explosive disorder; 80 percent were men.

The disorder follows a chronic or episodic course and is associated with distress, morbidity (for example, accidents), and social and occupational impairment. In the NCS-R, IED had a mean age at onset of 14 years, was persistent over the life course (with average of 6.2 – 11.8 years with attacks), and was associated with substantial role impairment. The prevalence of the disorder was much lower in persons aged 60 years and older.

Family studies suggested that first-degree relatives of people with IED have high rates of impulsive violence, substance misuse, and possibly mood and other impulsive control disorders. A blinded, controlled family history study using broadly defined IED criteria found a significantly increased morbid risk of the condition in relatives of affected probands (26%), compared with relatives of control probands (8%).

In terms of neurobiology, people with emotion dysregulation and aggression have been shown to have disturbed serotonergic function and functional abnormalities in both the limbic system and the orbitofrontal cortex.

In a functional magnetic resonance imaging (MRI) study of response to social threat, ten subjects with IED showed exaggerated amygdale reactivity and diminished orbitofrontal cortex activation to faces expressing anger, compared with controls. The authors noted these findings were similar to other disorders characterized by impulse aggression, including borderline personality disorder and bipolar disorder, and that they supported a link between a dysfunctional frontal-limbic network and aggression.

Treatment

Interventions for patients who have IED is difficult because of their angry outburst; however, a combined pharmacological and psychotherapeutic approach has the best chance of success. Group psychotherapy may be helpful, and family therapy is useful, particularly when the explosive patient is an adolescent or a young adult. A goal of therapy is to have the patient recognize and verbalize the thoughts or feelings that precede the explosive outbursts instead of acting them out.

Anticonvulsants have long been used, with mixed results, in treating explosive patients. Lithium (Eskalith) has been reported useful in generally lessening aggressive behavior, and carbamazepine, valproate (Depakene) or divalprex (Depakote), and phenytoin (Dilantin) have been reported helpful. Some clinicians have also used other anticonvulsants (e.g., gabapentin [Neurontin]). Benzodiazepines are sometimes used but have been reported to produce a paradoxical reaction of dyscontrol in some cases.

Antipsychotics (e.g., phenothiazines and serotonin-dopamine antagonists) and tricyclic drugs have been effective in some cases, but clinicians must then question whether schizophrenia or a mood disorder is the true diagnosis. With a likelihood of subcortical seizure-like activity, medications that lower the seizure threshold can aggravate the situation. Selective serotonin reuptake inhibitors (SSRIs), trazodone (Desyrel), and buspirone (BuSpar) are useful in reducing impulsivity and aggression.