|Description:||The PHQ-9 is a brief, self-rated questionnaire used to screen for symptoms of depression evident over the past two-week period.|
|Disease States:||Major depressive disorder|
|Validated Uses:||Screening, Diagnosis, Treatment Monitoring & Evaluation, Symptom Severity|
|Populations:||Adolescent, Adult, Geriatric|
|Time to administer:||< 5 minutes|
|Commonly used in:||Clinical Trials & Research, Clinical Practice|
The PHQ-9 depression scale is derived from the depression module of the Patient Health Questionnaire (PHQ)1,5 and intended for use in a primary care setting.2,5,10 Each item corresponds to 1 of the 9 depressive symptoms defined by the Diagnostic and Statistical Manual of Mental Disorders-IV (DSM-IV) and is ranked according to frequency on a scale from 0–3 (0 = not at all, 1 = several days, 2 = more than half the days, 3 = nearly every day).1 Major depressive disorder can be diagnosed with the PHQ-9 scale if 5 or more of the 9 depressive symptom criteria are present at least “more than half the days” in the past two weeks, and 1 of those symptoms is depressed mood or anhedonia.1,5 The 9 items are also summed to create a total score ranging between 0 and 27.1 A diagnosis of depression can also be made based on the total score, with a cutoff threshold of greater than or equal to 10.2,6,10 Please note that the clinician is encouraged to rule out physical causes of depression, normal bereavement, and any history of mania prior to making a diagnosis of major depressive disorder.1,5
For patients who checked off any problems, the PHQ-9 scale also includes one global item assessing functional impairment (“How difficult have these problems made it for you to do your work, take care of things at home, or get along with other people?”).1 This item is not included in the diagnostic portion of the instrument and does not contribute to the total score, but may be useful to clinicians in making decisions about initiating and/or adjusting treatment.5
Note: Although the PHQ-9 was initially developed with DSM-IV criteria, the scale is also compatible with the DSM-5. The core criteria for major depressive disorder are consistent across these editions12.
|Scale Validity:||According to a large meta-analysis that included 26 studies and 26,902 people with and without major depressive disorder,10 the PHQ-9 diagnostic algorithm showed a sensitivity of 58.4% and specificity of 92.1%.10 The PHQ-9 scale total score (with cutoff of 10) showed a sensitivity of 82.2% and specificity of 84.7%.10|
|Alternative Versions:||The PHQ-9 scale is the abbreviated, depressive disorder-specific version of the original PHQ and is part of a family of scales.5 The PHQ is the self-administered version of the Primary Care Evaluation of Mental Disorders (PRIME-MD), a validated tool for diagnosing common mental disorders.5
GAD, Generalized Anxiety Disorder; PHQ, Patient Health Questionnaire; PRIME-MD, Primary Care Evaluation of Mental Disorders; SADS, Somatoform, Anxiety, and Depressive Symptoms.
|Cited Limitations:||Item 9 of the PHQ-9 scale evaluates a patient’s thoughts of death or self-injury over the last two weeks and is often used to screen patients for potential suicide risk.1,15 Please note that recent studies have failed to validate item 9 of the PHQ as a useful measure of suicidality as it demonstrates poor predictive power and a high false-positive rate.15 It has been suggested that the PHQ-9 suicide item could be useful as an initial screening measure if coupled with a more specific and comprehensive suicide risk scale, such as the Columbia Suicide Severity Rating Scale, but more research is needed to support this use.15|
†Although the depression-specific PHQ-9 scale is described here, we include information about alternative versions of the PHQ for your general awareness and convenience. You may see these alternative versions used by different practitioners or in clinical trial or research settings.
Supporting references for the filters are as follows:
Disease States: Major depressive disorder1,2; Validated Uses: Screening3,4, Diagnosis1,4-6, Treatment Monitoring & Evaluation4,5, Symptom Severity1,5; Populations: Adolescent3,7,8, Adult1,3,4, Geriatric9; Administration Method: Self-report1,3,4; Time to administer: < 5 minutes3,8; Commonly used in: Clinical Trials & Research1,5,9, Clinical Practice1,6,9-11
- Kroenke, K et al. J Gen Intern Med. 2001;16(9):606-613.
- Levis, B et al. BMJ. 2019;365:l1476.
- Lam, R et al. Assessment Scales in Depression, Mania and Anxiety. (Taylor & Francis Group, 2005).
- Beidas, RS et al. Cogn Behav Pract. 2015;22(1):5-19.
- Instructions for Patient Health Questionnaire (PHQ) and GAD-7 Measures. 2020. https://www.phqscreeners.com/. Accessed June 15, 2020.
- Gilbody, S et al. J Gen Intern Med. 2007;22(11):1596-1602.
- Richardson, LP et al. Pediatrics. 2010;126(6):1117-1123.
- Sinclair-McBride, K et al. Psychiatr Serv. 2018;69(7):837-838.
- Zhang, H et al. Geriatr Gerontol Int. 2020;20(2):138-143.
- Mitchell, AJ et al. BJPsych Open. 2016;2(2):127-138.
- STABLE National Coordination Council. Standards for bipolar excellence resource toolkit. 2015.
- Center for Behavioral Health Statistics and Quality. 2014 National Survey on Drug Use and Health: DSM-5 Changes: Implications for Child Serious Emotional Disturbance (unpublished internal documentation). 2016. Substance Abuse and Mental Health Services Administration. Rockville, mD.
- Spitzer, RL et al. JAMA. 1994;272(22):1749-1756.
- Torres Soler, C et al. Nord J Psychiatry. 2018;72(3):184-190.
- Na, PJ et al. J Affect Disord. 2018;232:34-40.