Although impulse-control disorders are often thought to be rare conditions, a recent replication of the National Comorbidity Study demonstrated a 12-month prevalence rate of 8.9%. This percentage, however, also included disorders such as oppositional defiant disorder (1%), conduct disorder (1%), and attention-deficit/hyperactivity disorder (ADHD) (4.1%). Intermittent explosive disorder was reported at 2.6% of the surveyed population. Intermittent explosive disorder and pathological gambling (0.2–3.3% of populations surveyed) are much more common than the other disorders in this group.
INTERMITTENT EXPLOSIVE DISORDER
The National Comorbidity Study Replication reported a 12-month prevalence rate of 2.6%. This is more common than previously realized.
The outbursts associated with intermittent explosive disorder (sometimes referred to as episodic dyscontrol) were initially viewed as the result of limbic system discharge or dysfunction or even as interictal phenomena. The Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5), does now exclude those patients in whom an aggressive episode was thought to be related to a general medical condition (e.g., temporal lobe seizures, delirium) or to the direct psychological effects of a substance, whether a drug of abuse or a prescribed medication. Disorders that can be identified as resulting from neurological insult or a seizure disorder are now classified elsewhere. Nevertheless, neurological soft signs, nonspecific electroencephalogram (EEG) anomalies, or mild abnormalities on neuropsychological testing have been noted in patients given this diagnosis.
Psychodynamic explanations have also been proposed. Childhood abuse is thought to be a risk factor for the development of this disorder. Others postulate narcissistic vulnerability as a possible mechanism that triggers these attacks. Thus, one can conceptualize the "explosive" episodes as resulting from a real or perceived insult to one's self-esteem or as a reaction to a perceived threat of rejection, abandonment, or attack.
Little is known about the genetics of intermittent explosive disorder. Family studies of individuals with this disorder have shown high rates of mood and substance-use disorders in first-degree relatives.
Aggressive outbursts occur in discrete episodes and are grossly out of proportion to any precipitating event. Furthermore, there is often a lack of rational motivation or clear-cut gain to be realized from the aggressive act itself. The patient expresses embarrassment, guilt, and remorse after the act and is often genuinely perplexed as to why he or she behaved in such a manner. Some patients have described periods of exhaustion and sleepiness immediately after these acts of violence.