Intermittent explosive disorder (IED)

Intermittent explosive disorder (IED) is an impulse-control disorder characterized by a failure to resist one’s aggressive impulses, which can lead to frequent “explosions”—incidents of verbal aggression in the form of temper tantrums, threats, or tirades, or physical attacks on other people and their possessions, causing bodily injury and property damage.

The degree of aggressiveness expressed during a typical IED episode is out of proportion to any provocation or situational stress. An individual may experience these episodes as "spells" or "attacks" in which the explosive behavior is preceded by a sense of tension or arousal, and followed by an immediate sense of relief and, often, sincere and genuine regret. Later, the individual may feel upset, remorseful, or embarrassed about their behavior.

Symptoms

Intermittent explosive disorder is marked by frequent and distinct episodes in which an individual fails to resist aggressive impulses or reactions grossly out of proportion to any provocation. In general, these outbursts are brief and impulsive, not premeditated, and last less than half an hour, but can result in serious acts of assault or property destruction.

To be diagnosed with IED, an individual must have displayed verbal or physical aggression toward property, animals, or other people approximately twice weekly for a period of at least three months. This aggression does not necessarily have to result in damage to property or injury in animals or other people. A person can also be diagnosed with IED if they have fewer but more destructive episodes; specifically, three such episodes within a 12-month period that result in damage to property, or physical assaults that lead to injury.

For an IED diagnosis to be made, the aggressive episodes may not be better accounted for by another disorder such as antisocial personality disorder, borderline personality disorder, a psychotic disorder, a manic episode, conduct disorder, or attention-deficit/hyperactivity disorder. They also may not be due to the direct physiological effects of a substance, such as a medication or a drug of abuse, or a general medical condition, such as head trauma or Alzheimer's disease.

Intermittent explosive disorder tends to be persistent with episodes occurring for many years. Therefore, the disorder can have serious consequences for an individual’s everyday life, leading to job loss, school suspension, divorce and irreparable damage to other close relationships, accidents (such as car accidents), hospitalization due to injuries, financial problems, or incarceration or other serious legal problems. People with IED may sometimes be prone to self-harm or suicidal ideation.

How common is intermittent explosive disorder?

Previous estimates had suggested that IED could be found in approximately 2.7 percent of the general population, but many experts believe it may be much more common and that it may be an underrecognized cause of much violent behavior. One study from the National Institute of Mental Health (NIMH) suggested that, broadly defined, IED may actually affect as many as 7.3 percent of adults, or as many as 16 million Americans. Those with persistent and more destructive recurring episodes of IED may have, on average, 43 such attacks over the course of a lifetime.

Causes

Intermittent explosive disorder appears to emerge from a combination of biological and environmental factors. There may be a genetic component through which susceptibility to the disorder is passed from parents to children. There is also some evidence that the neurotransmitter serotonin may play a role in the development of IED. But many people with the disorder also grew up in families in which explosive behavior and verbal and physical abuse were common. Being exposed to such violence as a child, research finds, makes one more likely to develop the same traits as they mature; in other words, at least in part, the behavior may be learned.

How does intermittent explosive disorder appear in the brain?

People with intermittent explosive disorder may have differences in brain structure and function that distinguish them from others. Some research suggests that IED is linked to disruptions in serotonin pathways in the brain; other studies have found that it is associated with lower white matter integrity and lower grey matter volume in the connections between the frontal lobe and other brain regions. This deficit may contribute to impaired social cognition and greater difficulty regulating emotions.

Treatment

Treatment of IED, while challenging, can also be highly effective, particularly if it's started as early as possible, and eventually help individuals limit and control their aggressive impulses. School-based violence prevention programs, for example, may lead to early identification of IED cases, leading to treatment that could prevent associated psychopathology.

Treatment typically involves a combination of medication and psychotherapy; studies show that a combination of both approaches offers the best prognosis. Cognitive behavioral therapy can help individuals recognize their impulses and develop coping mechanisms such as relaxation techniques for keeping rage at bay during an episode. Group counseling and anger management programs can also be helpful.

Studies suggest that patients with intermittent explosive disorder can benefit from treatment with antidepressants, anti-anxiety agents in the benzodiazepine family, anticonvulsants, and mood stabilizers. Since IED can be comorbid with conditions such as anxiety or depression, clinicians need to factor that into their treatment plan, especially if medication is used.