PHQ-9
The PHQ-9 is the nine item patient self-report depression scale of the Patient Health Questionnaire. It is a powerful tool for assisting clinicians in making criteria-based diagnoses of depression and assessing the severity of depressive orders. The measure’s sensitivity to severity makes it useful in monitoring response to treatment. The PHQ-9 is based directly on the diagnostic criteria for major depressive disorder in the Diagnostic and Statistical Manual Fourth Edition (DSM-IV) and has excellent psychometric properties.
A benefit of the PHQ-9 is that it is easy to interpret. PHQ-9 score ≥10 had a sensitivity of 88% and a specificity of 88% for major depression. PHQ-9 scores of 5, 10, 15, and 20 represent mild, moderate, moderately severe, and severe depression, respectively.
