This Depression Test is designed to help you evaluate the severity of your depression with just nine simple questions. This app uses the Patient Health Questionnaire (PHQ-9), an empirically-based, self-test questionnaire. Clinical depression is a mood disorder in which feelings of sadness, loss, anger, or frustration interfere with everyday life for weeks or longer. Clinical depression generally responds positively to treatment, so it is important to seek treatment if you are concerned about your mental health.