Patient Health Questionnaire-9 (PHQ-9) A 9-item scale using each of the 9 DSM-IV criteria with self-reported frequency of "0" (not at all) to "3" (nearly every day). One of the most widely used instruments to assess depression, PHQ-9 scores of 5, 10, 15, and 20 represent mild, moderate, moderately severe, and severe depression, respectively. PHQ01 PHQ-9 SCDO:0000870 Patient Health Questionnaire - 9 Item Patient Health Questionnaire-9 Sufficient NCIT:C103526 Kroenke K, Spitzer R, Williams W. The PHQ-9: Validity of a brief depression severity measure. Journal of General Internal Medicine. 2001; 16: 606-616. Quality of Life Measure Quality of Life and Care Diagnostic Instrument