Coccaro EF - In this study, the researcher investigated the aspects of psychiatry comorbidity in Intermittent Explosive Disorder (IED) in order to examine the validity of IED in the context of other psychiatric disorders. Data from the National Comorbidity Study – Revised (n = 9,282 adults) and its Adolescent Supplement (n = 10,148 adolescents) and a large clinical research data set (n = 1,640), were analyzed. Outcomes revealed cases with IED had comorbidity similar to that noted in other, more established, Non-IED disorders. The researcher observed prior development of IED to the onset of most comorbid disorders and frequently higher aggression scores in those with IED and a comorbid disorder vs those with IED alone. These observations support the rationale of making a diagnosis of both IED and the comorbid disorder when both are present.