Patient Health Questionnaire (PHQ-9)

The PHQ-9 asks how often nine specific problems have bothered a person over the past two weeks: low interest, low mood, sleep trouble, fatigue, appetite change, feeling like a failure, trouble concentrating, moving or speaking noticeably slowly or restlessly, and thoughts of being better off dead.

Those nine items map exactly onto the nine diagnostic criteria for a major depressive episode, which is why the same answers work both as a screen and as a severity score. Each is rated 0 to 3, totalling 0 to 27. Bands run 0–4 minimal, 5–9 mild, 10–14 moderate, 15–19 moderately severe, and 20–27 severe. A tenth question asks how much the symptoms have interfered with daily life; it is recorded but not scored.

Licensing Notes: The PHQ-9 is in the public domain, and the official form states that no permission is required to reproduce, translate, display, or distribute it.

Learn More: The PHQ-9 measures severity, not diagnosis: a high score means symptoms are frequent, not that criteria are met.