What is the PHQ-9?

The Patient Health Questionnaire-9(PHQ-9) is a validated, widely used screening tool for identifying and monitoring symptoms of depression. Developed by Pfizer in 2010, this 9-item self-report scale is frequently used in both mental health and primary care settings to support clinical decision-making. It is endorsed by organizations such as the American Psychological Association (APA), the American Psychiatric Association (APA), and the National Institute for Health and Care Excellence (NICE).

Use in Clinical Settings

Although originally developed for use in mental health, the PHQ-9 is now a common tool among a wide range of healthcare professionals—including primary care physicians, nurse practitioners, and behavioral health specialists—as part of routine depression screening and treatment planning.

How It Works

Patients are asked to reflect on the previous two weeks and indicate how often they’ve been affected by each of the nine core symptoms of depression. Each item is scored on a 0–3 scale, where:

• 0 = Not at all

• 1 = Several days

• 2 = More than half the days

• 3 = Nearly every day

A total score is generated by summing responses to all nine items, yielding a maximum score of 27.

Scoring and Interpretation

PHQ-9 scores fall into the following general severity ranges:

• 0–4: Minimal or no depression

• 5–9: Mild depression

• 10–14: Moderate depression

• 15–19: Moderately severe depression

• 20–27: Severe depression

These scores offer a subjective view of how patients are feeling and help clinicians track symptom changes over time. For example, a score of 16 would indicate moderately severe depressive symptoms and may signal a need for intervention.

Clinical Considerations

While the PHQ-9 is a valuable tool, it should not be used in isolation. Questionnaire results reflect subjective symptoms and must be interpreted alongside clinical interviews, cognitive assessments, and the patient’s overall mental health history, level of distress, and functional impact.

For more information, refer to the official PHQ-9 instruction manual and the Creyos Standardized Questionnaires Guide, which includes a complete list of available behavioral and cognitive health screeners.