This article includes discussion of intermittent explosive disorder and episodic dyscontrol. The foregoing terms may include synonyms, similar disorders, variations in usage, and abbreviations.
Intermittent explosive disorder, as described in the DSM-5 (04), represents the categorical expression of recurrent, problematic, impulsive aggression. Diagnostic criteria include impulsive aggressive outbursts, disproportionate to provocation, that occur at least twice weekly for 3 months for low intensity outbursts and/or at least 3 high intensity outbursts including serious physical assault on another person or destruction of property of more than trivial value. Most individuals with intermittent explosive disorder report both types of aggressive outbursts. Neurobiological studies suggest reduced central serotonergic (5-HT) function, reduced frontal-limbic grey matter, and an inverse correlation with aggression overall, and enhanced amygdala response to social threat in those with intermittent explosive disorder. Psychologically, individuals with intermittent explosive disorder display increased hostile attribution bias and negative emotional response to socially ambiguous interactions. Impulsive aggressive behavior in those with intermittent explosive disorder may be treated with 5-HT selective uptake inhibitors (eg, fluoxetine), lithium, and some other mood stabilizing agents.
Historical note and terminology
The essence of intermittent explosive disorder has been included in the Diagnostic and Statistical Manual of Mental Disorders since its inception. In 1952, “passive aggressive personality, aggressive type” was included in the DSM-1 (01) and represented the presentation of those who responded to stress and provocation with aggressive outbursts. By DSM-2 (02), this was listed as “explosive personality disorder”. By DSM-3 (03), this was changed to “intermittent explosive disorder” and represented something akin to “episodic dyscontrol” with the idea that such aggressive outbursts were caused by seizures stemming from an irritable limbic focus. However, diagnostic criteria were incompletely operationalized and the exclusion of inter-outburst aggression and/or impulsivity, as well as other diagnostic exclusions, made it appear that intermittent explosive disorder was quite rare. Psychobiological study of impulsive aggression, and the observation that some medications could reduce this behavior, led to the idea that intermittent explosive disorder was not due to seizure-like activity at a limbic focus but due to a balance of inhibitory and excitatory influences in cortico-limbic structures. Over the course of research in the past 2 decades, the idea that intermittent explosive disorder is a disorder of impulsive aggression (08) gained sufficient diagnostic validity to justify recognition and inclusion in DSM-5 (04). Although the corresponding alternative classification in ICD-10 (57) is not as well defined as in DSM-5, we expect this to change in ICD-11. Finally, there has been considerable research undertaken to differentiate children and adolescents with aggression and irritability from those with similar symptomatology but who experience bipolar disorder. This has particular relevance to child and adolescent psychiatry with expectation of the evolution of a new diagnostic entity, “disruptive mood dysregulation disorder” with aggressive episodes as part of a mood disorder, contrasted with an impulsive control disorder (36).