Intermittent explosive disorder: Associations with PTSD and other Axis I disorders in a US military veteran sample

• We examine prevalence of IED and its associations with PTSD in trauma-exposed veteran sample.
• Examine structural associations between IED and internalizing–externalizing psychopathology.
• Regression analyses revealed lifetime PTSD severity as significant predictor of IED severity.
• CFA revealed significant cross-loadings of IED on both externalizing and distress.
• IED comorbidity may reflect underlying tendencies in aggression and generalized distress.

This study examined the prevalence of intermittent explosive disorder (IED) and its associations with trauma exposure, posttraumatic stress disorder (PTSD), and other psychiatric diagnoses in a sample of trauma-exposed veterans (n = 232) with a high prevalence of PTSD. Structural associations between IED and latent dimensions of internalizing and externalizing psychopathology were also modeled to examine the location of IED within this influential structure. Twenty-four percent of the sample met criteria for a lifetime IED diagnosis and those with the diagnosis were more likely to meet criteria for lifetime PTSD than those without (30.3% vs. 14.3% respectively). Furthermore, regression analyses revealed lifetime PTSD severity to be a significant predictor of IED severity after controlling for combat, trauma exposure, and age. Finally, confirmatory factor analysis revealed significant cross-loadings of IED on both the externalizing and distress dimensions of psychopathology, suggesting that the association between IED and other psychiatric disorders may reflect underlying tendencies toward impulsivity and aggression and generalized distress and negative emotionality, respectively.