Participants will be assessed for depression severity using the Patient Health Questionnaire (PHQ), a validated, self-administered diagnostic instrument for common mental disorders. The PHQ-9 score can range from 0 to 27 with 0 = "No" depression and 27 = "Severe" depression.
The PHQ is a validated, self-administered version of the Primary Care Evaluation of Mental Disorders (PRIME-MD) diagnostic instrument for common mental disorders. The PHQ-9 is the depression module, which scores each of the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition (DSM-IV) depression criteria as "0" (not at all) to "3" (nearly every day). A PHQ-9 score of 10 or greater has 89% sensitivity and 88% specificity for major depression. PHQ-9 scores of 5, 10, 15, and 20 represented mild, moderate, moderately severe, and severe depression, respectively. PHQ-9 is a validated tool for diagnosis of depression and monitoring response to interventions.