If you’ve been feeling low, experiencing changes in sleep or appetite, or losing interest in things you once enjoyed, you might be wondering about depression. It’s important to understand that assessing your mental health is a crucial first step, and tools like the Depression Diagnosis Questionnaire, specifically the Patient Health Questionnaire-9 (PHQ-9), can be valuable resources. However, it is critical to remember that this questionnaire is intended to be reviewed and interpreted by a healthcare professional, not for self-diagnosis.
The PHQ-9 is a widely used self-administered questionnaire derived from the PRIME-MD diagnostic tool for common mental disorders.1 It functions as the depression module of the broader PRIME-MD, evaluating the nine DSM-IV criteria for depression. Each criterion is scored based on how often you’ve experienced it over the past two weeks, ranging from “not at all” (0) to “nearly every day” (3). The PHQ-9 has been rigorously validated for use in primary care settings, making it a practical tool for healthcare providers.2
It’s important to distinguish that the PHQ-9 is not primarily designed as a depression screening questionnaire for the general population. Instead, it is effectively used to monitor the severity of diagnosed depression and track a patient’s response to treatment. That being said, in certain at-risk groups, such as individuals with coronary heart disease or those recovering from a stroke, the PHQ-9 can be helpful in making an initial, tentative diagnosis of depression.34
For broad depression screening, a shorter version called the Patient Health Questionnaire (PHQ-2) is often used initially. The PHQ-2 demonstrates high sensitivity (97%) in identifying potential depression cases, though its specificity (67%) means it may sometimes indicate depression when it is not present.5 If the PHQ-2 suggests possible depression, the more detailed PHQ-9 can then be administered for a more in-depth assessment. The PHQ-9 itself shows a 61% sensitivity and a higher specificity of 94% in adults.
The Patient Health Questionnaire (PHQ-9) – Your Depression Assessment Tool
To help you understand the questions involved, here are the questions from the Patient Health Questionnaire (PHQ-9). Remember, this is for informational purposes and should not replace a consultation with your doctor.
Over the last two weeks, how often have you been bothered by any of the following problems?
- Little interest or pleasure in doing things?
- Feeling down, depressed, or hopeless?
- Trouble falling or staying asleep, or sleeping too much?
- Feeling tired or having little energy?
- Poor appetite or overeating?
- Feeling bad about yourself – or that you are a failure or have let yourself or your family down?
- Trouble concentrating on things, such as reading the newspaper or watching television?
- Moving or speaking so slowly that other people could have noticed? Or the opposite – being so fidgety or restless that you have been moving around a lot more than usual?
- Thoughts that you would be better off dead, or of hurting yourself in some way?
Understanding Your PHQ-9 Score: Depression Severity
Once you’ve considered these questions, the PHQ-9 provides a scoring system to help healthcare professionals understand the severity of any potential depression.
Depression severity scale:
- 0-4: No depression
- 5-9: Mild depression
- 10-14: Moderate depression
- 15-19: Moderately severe depression
- 20-27: Severe depression
The validity of the PHQ-9 has been rigorously evaluated against interviews conducted by mental health professionals. A PHQ-9 score of 10 or greater demonstrates a sensitivity of 88% and a specificity of 88% for identifying major depression.1 Importantly, its utility extends to telephone-based assessments, making it accessible in various healthcare delivery models.6
In conclusion, while the PHQ-9 depression diagnosis questionnaire is a valuable tool for assessing and monitoring depression severity, it is not a substitute for professional medical advice. If you are concerned about your mood or if your self-assessment suggests you might be depressed, please reach out to your doctor for a comprehensive evaluation and guidance. If you are experiencing thoughts of self-harm, please seek immediate help and refer to resources like Dealing with Suicidal Thoughts for support and available assistance.
(Note about credits)
The PHQ-9 was developed by Drs. Spitzer, Williams, and Kroenke with previous copyright held by Pfizer. Currently, no permission is needed to use, reproduce, translate, or distribute the PHQ-9.
References
[1] Kroenke K, Spitzer RL, Williams JB; The PHQ-9: validity of a brief depression severity measure. J Gen Intern Med. 2001 Sep 16(9):606-13.
[2] Cameron IM, Crawford JR, Lawton K, et al; Psychometric comparison of PHQ-9 and HADS for measuring depression severity in primary care. Br J Gen Pract. 2008 Jan 58(546):32-6. doi: 10.3399/bjgp08X263794.
[3] Haddad M, Walters P, Phillips R, et al; Detecting depression in patients with coronary heart disease: a diagnostic evaluation of the PHQ-9 and HADS-D in primary care, findings from the UPBEAT-UK study. PLoS One. 2013 Oct 10 8(10):e78493. doi: 10.1371/journal.pone.0078493.
[4] de Man-van Ginkel JM, Gooskens F, Schepers VP, et al; Screening for post stroke depression using the patient health questionnaire. Nurs Res. 2012 Sep-Oct 61(5):333-41.
[5] Maurer DM; Screening for depression. Am Fam Physician. 2012 Jan 15 85(2):139-44.
[6] Pinto-Meza A, Serrano-Blanco A, Penarrubia MT, et al; Assessing depression in primary care with the PHQ-9: can it be carried out over the telephone? J Gen Intern Med. 2005 Aug 20(8):738-42.
