The Patient Health Questionnaire (PHQ) is a 9 question self-administered diagnostic for measing the severity of depression. It scores each of the 9 DSM-IV criteria for depression as “0” (not at all) to “3” (nearly every day). PHQ-9 scores of 5, 10, 15, and 20 represented mild, moderate, moderately severe, and severe depression, respectively. While short, the PHQ-9 remains a reliable and valid measure of depression severity.