Factor analysis of treatment response in posttraumatic stress disorder

Factor analysis is applied to the symptoms of posttraumatic stress disorder (PTSD) to reduce the multidimensional symptom space to 2 dimensions; 1 dimension strongly correlated with depressive symptoms and 1 independent dimension weakly correlated with depressive symptoms. These factors are used to assess whether the effectiveness of an antidepressant medication is due to its antidepressant effect. The treatment is shown to be effective in both dimensions. The factor analysis sheds light on the symptom structure of PTSD, supports PTSD as a distinct psychiatric disorder, and supports the current diagnostic criteria.