Patient Health Questionnaire-9 (PHQ-9)

What is the PHQ-9?

The Patient Health Questionnaire-9 (PHQ-9) is a self-administered, validated survey developed to assess and monitor depression severity in adults. It is derived from the longer PHQ assessment, which in addition to depression, also includes modules that assess anxiety, somatoform, alcohol, and eating disorders. The PHQ-9 questionnaire consists of nine questions that focus on the DSM-IV diagnostic criteria for major depressive disorder (MDD). Eight (8) questions directly assess symptoms of depression and one (1) question assesses how any depressive symptoms have been impacting a patient’s ability to function.(1)

The PHQ and PHQ-9 were originally developed in 1999 by Dr. Robert L. Spitzer, Dr. Janet Williams, and Dr. Kurt Kroenke out of Columbia University. Prior to the PHQ, mental health specialists utilized the Primary Care Evaluation of Mental Disorders (PRIME-MD), which was a lengthy two-stage assessment consisting of a 26-item questionnaire that is completed by the patient, followed by a “clinician evaluation guide” that needs to be administered by the physician. Therefore, the PHQ was developed out of the need for a PRIME-MD version that was quicker to complete and entirely self-administered.(2) 

PHQ-9 Structure and Scoring

For each question of the PHQ-9, there are four choices to choose from in regard to how often a patient has been experiencing symptoms over the last two weeks. The last question screens for the risk of self harm.(2) Each answer is assigned points 0-3: Selecting “Not At All” is 0 points, “Several Days” is 1 point, “More Than Half of the Days” is 2 points, and “Nearly Every Day” is 3 points. Adding up the points from all nine questions will provide a 0-27 depression severity score. Interpretation of the score is shown below: (3)

A score of 10 or greater should be viewed as a “yellow flag” suggesting the possibility of a condition of clinical significance. A score of 15 is seen as a “red flag”, and is indicative of a patient who likely needs active treatment.(3) 

Strengths

The PHQ-9 is considered among the best-validated and widely used depression scales in both clinical practice and research. It is both quick to fill out by the patient and easily scored by a healthcare professional. In addition, it can be administered repeatedly, so scores can be used to reflect improvement or worsening of depression in response to a treatment.(1) Because the PHQ-9 is derived from the PHQ, it also can be used alone or in addition to multiple modules in the PHQ. The PHQ-9 has also been translated and validated into multiple languages other than English.(4)

Considerations 

Although the PHQ-9 is a helpful tool for identifying depression or the level of change in a patient’s depression, further clinical consideration is necessary regarding the patient’s diagnosis management and treatment.(4) Also, because the PHQ-9 is a self-reported assessment, clinicians must take into account how well the patient understood the questions as well as other relevant information from the patient, their family or other sources in order to make a diagnosis.(3)

Alternative Depression Surveys

The following are some alternative, validated and reliable instruments that can also be used to measure depression (5,6):

• PHQ-2: Two-question tool that can be used as a “first step” approach for depression screening. Patients who screen positive should be evaluated with the full PHQ-9 to determine if they meet the criteria for a depressive disorder. 
• PROMIS Depression: Can be administered by Computerized Adaptive Testing (CAT) for flexible administration.
• Beck Depression Inventory (BDI): Screens for depression and measures behavioral manifestations of depression and is validated for use on individuals age 13-80. 
• CES-D: Screener for depression in primary care settings and designed for use in the general population. The scale takes about 20 minutes to administer and score.
• EQ-5D: Measures quality of life in five areas: mobility, self-care, usual activities, pain/discomfort, and anxiety depression.
• HAM-D: Measures depression in individuals before, during, and after treatment, but must be administered by a clinician.
• MADRS: Adaptation of the HAM-D that has a greater sensitivity to change over time; however, it takes 20-30 minutes to complete.

Licensing

The Patient Health Questionnaire-9 is free to use and does not have any licensing requirements.(7) 

Resources

1. Test Review: Patient Health Questionnaire–9 (PHQ-9)
2. Validation and Utility of a Self-Report Version of PRIME-MD The PHQ Primary Care Study
3. Quick Guide to PRIME-MD Patient Health Questionnaire (PHQ)
4. PHQ and GAD-7 Instructions
5. Depression Assessment Instruments
6. Patient Health Questionnaire-2 (PHQ-2)
7. Patient Health Questionnaire (PQH) Screener Overview