Psychotic features in chronic posttraumatic stress disorder and schizophrenia: comparative severity.

Psychotic features are frequent in combat veterans with chronic posttraumatic stress disorder (PTSD), may correlate with severity of PTSD symptoms, and may reflect a distinct subtype of the disorder. These psychotic features include auditory and visual hallucinations and delusional thinking that is usually paranoid in nature. Psychotic features may be under-recognized in chronic PTSD because patients are reluctant to report these symptoms and because they may not have overt changes in affect or bizarre delusions characteristic of other psychoses, e.g., schizophrenia. To further assess these phenomena, we compared clinical ratings on the Positive and Negative Syndrome Scale (PANSS) and other assessments, including the Clinical Global Impression Scale and the Structured Clinical Interview with Psychotic Screen, in veterans meeting DSM-IV criteria for chronic PTSD with well-defined comorbid psychotic features (N = 40) or chronic schizophrenia (N = 40). The patients with schizophrenia had modestly higher composite PANSS scores and positive symptom scores although average scores in both groups were moderate to severe in intensity. Negative symptom and general psychopathology subscale scores were comparable in both groups. Regarding specific positive symptoms, hallucinations were comparable between groups in severity; however, schizophrenia patients had slightly more intense delusions and conceptual disorganization. These data further validate the occurrence of positive as well as negative symptoms of psychosis in chronic PTSD in a range of severity that may approach that of patients with schizophrenia. Although meeting DSM-IV criteria for two different major psychiatric disorders, these two patient populations were remarkably similar with respect to not only positive but also negative symptoms.