The factor structure of major depression symptoms: A test of four competing models using the Patient Health Questionnaire-9

Little research has examined the underlying symptom structure of major depressive disorder (MDD) symptoms based on DSM-IV criteria. Our aim was to analyze the symptom structure of major depression, using the Patient Health Questionnaire-9 (PHQ-9). The PHQ-9 was administered to a sample of 2615 Army National Guard soldiers from Ohio. A one-factor model of depression and three separate two-factor models previously established in the literature...