Abstract
This study examined aspects of psychiatry comorbidity in Intermittent Explosive Disorder (IED) in order to explore the validity of IED in the context of other psychiatric disorders. Data from the National Comorbidity Study - Revised (NCS-R: n = 9,282 adults) and its Adolescent Supplement (NCS-AS: n = 10,148 adolescents) and a large clinical research data set (n = 1640) were analyzed in this study. Mean number of comorbid disorders among current IED participants was similar to that among other Non-IED disorders and comorbidity of IED with Non-IED disorders was similar to comorbidity among Non-IED disorders. When examined together, current IED was significantly comorbid with current bipolar, depressive, anxiety, substance use, and post-traumatic stress disorder, and age of onset of IED generally preceded that of the comorbid disorders. Finally, mean aggression scores were generally highest among those with IED and the comorbid disorder while scores among those with the comorbid disorder alone were generally less than that with IED or with IED and the comorbid disorder. Comorbidity in IED is similar to that in other, more established, Non-IED disorders. The observation that the development of IED precedes the onset of most comorbid disorders and that aggression scores in those with IED and a comorbid disorder are often higher than those with IED alone supports the rationale that a diagnosis of both IED and the comorbid disorder should be made when both are present.