About the PHQ-9
The PHQ-9 is a valuable tool for assessing depression severity and monitoring treatment response. It can be self-administered or conducted by a clinician, in person or via telephone, making it highly versatile for various healthcare settings. The questionnaire takes less than three minutes to complete, minimising patient burden whilst providing clinically meaningful information. Beyond screening, the PHQ-9 assists in diagnosing major depression and assessing symptom severity, with scores of 10 or higher suggesting the presence of a depressive disorder warranting further clinical evaluation.
Medical Specialties
Clinical Indications
Developer Information
The PHQ-9 was developed by Drs. Kurt Kroenke, Robert L. Spitzer, and Janet B.W. Williams in 2001. It was derived from the longer Patient Health Questionnaire (PHQ) and is based on the diagnostic criteria for major depressive disorder in the DSM-IV (now DSM-5). The developers are affiliated with the Regenstrief Institute and Columbia University.
Copyright & Licensing
The PHQ-9 is in the public domain and is free to use without permission or licensing fees. It was developed with support from Pfizer Inc. and is available for use in clinical practice and research. No copyright restrictions apply.
Administration Instructions
Over the last 2 weeks, how often have you been bothered by any of the following problems? Please select the response that best describes how often you have been bothered by each problem.
Scoring Methodology
The PHQ-9 consists of 9 items, each scored on a 4-point Likert scale (0 = Not at all, 1 = Several days, 2 = More than half the days, 3 = Nearly every day). The total score is calculated by summing the responses to all 9 items, yielding a score ranging from 0 to 27. All items are weighted equally, and there are no subscales. The score can be calculated if at least 8 of 9 questions are answered, though all 9 questions should ideally be completed for a comprehensive assessment. Higher scores indicate greater severity of depressive symptoms.
Meaningful Change Threshold
A change of 5 points or more in the PHQ-9 score is considered a clinically meaningful change, indicating a significant improvement or worsening of depressive symptoms. A change of 3-4 points may also be meaningful in some clinical contexts. The minimal clinically important difference (MCID) has been reported as approximately 5 points in various studies.
Score Interpretation
Understanding what your score means
minimal depression
0 - 4Minimal depression - Patient experiences few or no depressive symptoms. No intervention typically required, though monitoring may be appropriate.
mild depression
5 - 9Mild depression - Patient experiences some depressive symptoms that may benefit from support, watchful waiting, or brief interventions.
moderate depression
10 - 14Moderate depression - Patient experiences significant depressive symptoms. Clinical intervention is recommended, which may include psychotherapy, medication, or both.
moderately severe depression
15 - 19Moderately severe depression - Patient experiences substantial depressive symptoms. Active treatment with psychotherapy and/or medication is strongly recommended.
severe depression
20 - 27Severe depression - Patient experiences very significant depressive symptoms. Immediate clinical intervention is warranted, and combination treatment (psychotherapy and medication) is typically recommended.
Subscales
This questionnaire measures multiple dimensions
Clinical Limitations & Considerations
Whilst the PHQ-9 is a reliable and valid measure, it is a screening tool and should not be used as the sole basis for diagnosis. A comprehensive clinical evaluation is necessary for definitive diagnosis. The questionnaire focuses on depressive symptoms over the past two weeks and may not capture longer-term patterns or contextual factors. Cultural and language differences may affect interpretation, and validated translations should be used for non-English speaking populations. Item 9 (suicidal ideation) requires immediate clinical attention regardless of total score. The PHQ-9 may be less sensitive in certain populations, such as those with severe cognitive impairment or very young patients.
Supporting Literature
Key validation and development studies for the PHQ-9
- 1
The PHQ-9: Validity of a brief depression severity measure
Kroenke K, Spitzer RL, Williams JBW
Journal of General Internal Medicine, 2001
- 2
The PHQ-9: A new depression diagnostic and severity measure
Kroenke K, Spitzer RL
Psychiatric Annals, 2002
- 3
Validation of the Patient Health Questionnaire-9 (PHQ-9) for major depressive disorder screening in adolescents
Richardson LP, McCauley E, Grossman DC, McCarty CA, Richards J, Russo JE, Rockhill C, Katon W
Pediatrics, 2010
- 4
Minimal clinically important difference on the Patient Health Questionnaire-9 for the treatment of depression
Löwe B, Unützer J, Callahan CM, Perkins AJ, Kroenke K
Journal of General Internal Medicine, 2004
- 5
Validation of the Patient Health Questionnaire-9 for major depressive disorder in the Chinese population
Chen S, Chiu H, Xu B, Ma Y, Jin T, Wu M, Conwell Y
General Hospital Psychiatry, 2010
- 6
Depression screening using the Patient Health Questionnaire-9 administered on a touch screen computer
Kroenke K, Spitzer RL, Williams JBW, Löwe B
Psychosomatics, 2009
- 7
The Patient Health Questionnaire-9 for measuring depressive symptoms among the general population and among women with postpartum depressive symptoms
Kroenke K, Spitzer RL, Williams JBW, Löwe B
Archives of Women's Mental Health, 2010
- 8
A systematic review of the psychometric properties of the Patient Health Questionnaire-9 (PHQ-9) in different populations
Kocalevent RD, Hinz A, Brähler E
Journal of Affective Disorders, 2013
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The Fatigue Assessment Scale (FAS) is a 10-item self-report questionnaire measuring the severity of fatigue. It includes two subscales: Physical Fatigue (Q1-5, range 5-25) and Mental Fatigue (Q6-10, range 5-25). Total score ranges from 10-50, with higher scores indicating greater fatigue.
This questionnaire is provided free of charge. Patient Watch charges only for platform services (data storage, automated reminders, analytics) - not for use of clinical instruments. This non-commercial model supports academic and clinical use. View full licensing disclosure