Measuring depression outcome with a brief self-report instrument: sensitivity to change of the Patient Health Questionnaire (PHQ-9)

Background: The nine-item depression module from the Patient Health Questionnaire (PHQ-9) is well validated and widely used as a brief diagnostic and severity measure, but its validity as an outcome measure for depression has not yet been established. Therefore, we investigated the sensitivity to change of the PHQ-9 in three groups of patients whose depression status either improved, remained unchanged, or deteriorated over time. Methods: From...