The internalizing and externalizing structure of psychiatric comorbidity in combat veterans

This study examined the latent structure of psychiatric disorders in a sample with a high prevalence of PTSD. A series of confirmatory factor analyses tested competing models for the covariation between Structured Clinical Interview for DSM‐III‐R diagnoses among 1,325 Vietnam veterans. The best‐fitting solution was a 3‐factor model that included two correlated internalizing factors: anxious‐misery, defined by PTSD and major depression, and fear, defined by panic disorder/agoraphobia and obsessive‐compulsive disorder. The third factor, externalizing, was defined by antisocial personality disorder, alcohol abuse/dependence, and drug abuse/dependence. Both substance‐related disorders also showed significant, albeit smaller, cross‐loadings on the anxious‐misery factor. These findings shed new light on the structure of psychiatric comorbidity in a treatment‐seeking sample characterized by high rates of PTSD.