Specificity of posttraumatic stress disorder symptoms: an investigation of comorbidity between posttraumatic stress disorder symptoms and depression in treatment-seeking veterans.

In response to high levels of comorbidity and symptom overlap between posttraumatic stress disorder (PTSD), major depressive disorder (MDD), and other disorders, much attention has been devoted to the role of specific and nonspecific symptoms among the disorders. The present study investigated the overlapping symptoms of PTSD and MDD in treatment-seeking veterans. Exploratory factor analyses were used to identify latent factors of both self-reported and clinician-rated symptoms of PTSD and MDD. Results of exploratory factor analyses supported a 2-factor model representing symptoms of depression and PTSD; however, a subset of PTSD symptoms, characterized by emotional numbing and dysphoria, loaded onto the depression factor, rather than the PTSD factor. These nonspecific PTSD symptoms were predictive of comorbid MDD and increased depression symptomatology in patients with PTSD. Together, these findings demonstrate the importance of accounting for nonspecific symptoms in diagnosis and treatment of PTSD, highlighting a need for revisions to our current diagnostics.