oPatientPlus articles are written by UK doctors and are based on research evidence, UK and European Guidelines. They are designed for health professionals to use, so you may find the language more technical than the condition leaflets.
This easy to use patient questionnaire is a self-administered version of the PRIME-MD diagnostic instrument for common mental disorders. The PHQ-9 is the depression module, which scores each of the nine DSM-IV criteria as "0" (not at all) to "3" (nearly every day). It has been validated for use in primary care.
It is not a screening tool for depression but it is used to monitor the severity of depression and response to treatment. However, it can be used to make a tentative diagnosis of depression in at-risk populations - eg, those with coronary heart disease or after stroke.
When screening for depression the Patient Health Questionnaire (PHQ-2) can be used first (it has a 97% sensitivity and a 67% specificity). If this is positive, the PHQ-9 can then be used, which has 61% sensitivity and 94% specificity in adults.
Validity has been assessed against an independent structured mental health professional (MHP) interview. PHQ-9 score ≥10 had a sensitivity of 88% and a specificity of 88% for major depression. It can even be used over the telephone.
Note about credits
The copyright for the PHQ-9 was formerly held with Pfizer, who provided the educational grant for Drs Spitzer, Williams and Kroenke who originally designed it. This is no longer the case and no permission is required to reproduce, translate, display or distribute the PHQ-9.
Further reading & references
- 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.
- 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.
- 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.
- de Man-van Ginkel JM, Gooskens F, Schepers VP, et al; Screening for poststroke depression using the patient health questionnaire. Nurs Res. 2012 Sep-Oct;61(5):333-41.
- Maurer DM; Screening for depression. Am Fam Physician. 2012 Jan 15;85(2):139-44.
- 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.
Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.
Dr Huw Thomas
Dr Hayley Willacy
Dr Colin Tidy