The PHQ-9 is a 9-question instrument given to patients in a primary care setting to screen for the presence and severity of depression. It is the 9-question depression scale from the Patient Health Questionnaire (PHQ). The results of the PHQ-9 may be used to make a depression diagnosis according to DSM-IV criteria and takes less than 3 minutes to complete. The total of all 9 responses from the PHQ-9 aims to predict the presence and severity of depression. The total sum of the responses suggests varying levels of depression. Scores range from 0 to 27. In general, a total of 10 or above is suggestive of the presence of depression. Source wikipedia page