How is the PHQ-9 used in mental health screening and monitoring?

• A. It screens for depressive symptoms and tracks changes over time or with treatment.
• B. It measures anxiety severity.
• C. It diagnoses bipolar disorder.
• D. It replaces clinical interviews.

Answer: (A)

The essential idea is that the PHQ-9 is a brief, self-administered measure used to screen for depressive symptoms and to monitor how those symptoms change over time or with treatment. It asks about nine possible depressive symptoms experienced over the past two weeks, with each item scored from 0 to 3 based on frequency. Adding these up gives a total score from 0 to 27, which helps gauge how severe the depression is and, because it’s quick to repeat, how it evolves with therapy or medication. Clinically, this makes it a practical tool for initial screening and for tracking response to treatment across visits, as well as for flagging relapse or the need to adjust care. It’s not designed to measure anxiety (a separate instrument like the GAD-7 assesses that), it does not diagnose bipolar disorder (that requires evaluating manic or hypomanic episodes), and it does not replace a full clinical interview, which remains essential for a definitive diagnosis and comprehensive assessment.