PRIME-MD / PHQ Clinical Screening Framework
Spitzer, R. L., Kroenke, K. & Williams, J. B. W. · 1999
Also known as: PRIME-MD · PHQ Framework
The PHQ family descends from the Primary Care Evaluation of Mental Disorders and applies a single design principle: map each questionnaire item directly onto a diagnostic criterion, so that a non-specialist can administer it and a positive screen points to a specific follow-up rather than to generalised concern. The PHQ-9 covers the nine DSM criteria for major depressive episode over the last two weeks; the PHQ-2 is its two-item first stage; the PHQ-15 covers somatic symptom burden. These are screening instruments with published sensitivity and specificity — they identify who warrants assessment, and they do not diagnose.
Clinical screening framework derived from the Primary Care Evaluation of Mental Disorders (PRIME-MD). Operationalizes DSM-IV diagnostic criteria into brief self-report screeners for depression (PHQ-9/PHQ-2), anxiety (GAD-7), somatization (PHQ-15), and other conditions. Not a diagnostic system — designed to identify probable cases for clinical follow-up.
- Source:
- Spitzer, R. L., Kroenke, K., & Williams, J. B. W. (1999). Validation and utility of a self-report version of PRIME-MD: the PHQ primary care study. JAMA, 282(18), 1737-1744.
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Evidence at a glance
- Empirical support
- Strong evidence
- Replication
- Well replicated
- Cross-cultural
- Mostly universal
- Meta-analyses
- 30 indexed
These ratings summarise the published literature on the theory, not the quality of any single test built on it. They are editorial judgements based on the sources listed below, and they change as evidence accumulates.
Historical Context
PRIME-MD, published by Spitzer and colleagues in 1994, was a clinician-administered instrument designed to bring structured psychiatric assessment into general practice, but it took too long for routine use. The 1999 self-administered Patient Health Questionnaire was the response, and Kroenke, Spitzer and Williams's 2001 validation of the PHQ-9 made it the most widely used depression screen in the world. Its adoption was accelerated by being free of licensing cost, and it now anchors measurement-based care and collaborative-care models in many health systems.
Constructs
Depression Severity
As operationalized in the PHQ-9 and PHQ-2 (Kroenke, Spitzer & Williams, 2001), depression severity is assessed by the frequency of the nine cardinal symptoms of Major Depressive Disorder specified in DSM-IV: anhedonia, depressed mood, sleep disturbance, fatigue, appetite change, guilt/worthlessness, concentration difficulty, psychomotor change, and suicidal ideation. Scores index symptom burden rather than categorical diagnosis.
Generalized Anxiety Severity
As operationalized in the GAD-7 (Spitzer, Kroenke, Williams & Löwe, 2006), anxiety severity is assessed by the frequency of seven core symptoms of Generalized Anxiety Disorder specified in DSM-IV: nervousness, uncontrollable worry, excessive worry, restlessness, difficulty relaxing, irritability, and fearfulness.
Somatic Symptom Severity
As operationalized in the PHQ-15 (Kroenke, Spitzer & Williams, 2002), somatic symptom severity is assessed by the frequency and bothersomeness of 15 common physical symptoms (headaches, pain, gastrointestinal, cardiovascular, etc.) that account for more than half of all outpatient visits and are often associated with functional impairment.
Instruments
- Patient Health Questionnaire — 9 item(PHQ-9)Kroenke, K., Spitzer, R. L., & Williams, J. B. W.2001
- Patient Health Questionnaire — 2 item(PHQ-2)Kroenke, K., Spitzer, R. L., & Williams, J. B. W.2003
- Generalized Anxiety Disorder 7-item scale(GAD-7)Spitzer, R. L., Kroenke, K., Williams, J. B. W., & Löwe, B.2006
- Patient Health Questionnaire — 15 item (Somatic Symptom Severity)(PHQ-15)Kroenke, K., Spitzer, R. L., & Williams, J. B. W.2002
Tests built on this theory
PHQ-9: Patient Health Questionnaire (Depression)
9-item depression severity screener based on DSM criteria.
Learn more →PHQ-15: Somatic Symptom Severity Scale
15-item somatic symptom severity screening for physical complaints linked to distress.
Learn more →PHQ-2: Ultra-Brief Depression Screener
Ultra-brief 2-item depression screening for depressed mood and anhedonia.
Learn more →GAD-7: Generalized Anxiety Disorder Scale
7-item anxiety severity screener for generalized anxiety disorder.
Learn more →Practical Applications
The PHQ-9 is used for depression screening in primary care, for severity grading, and for tracking response to treatment over time, which is its most valuable and least appreciated function. The PHQ-2 serves as a first-stage filter in high-volume settings. Score bands map to severity categories that inform stepped-care decisions. Outside clinical settings, the appropriate use is entirely self-referential: a score indicates whether a conversation with a clinician is warranted, and carries no diagnostic meaning on its own.
How It's Measured
Self-administered symptom-frequency items over a two-week window, summed to a total with published severity bands; sensitivity and specificity are cutoff-dependent and population-dependent.
Critiques & Limitations
The conventional cutoff of 10 was derived in populations with relatively high depression prevalence; applied for universal screening in low-prevalence settings, it produces a majority of false positives, which is the core of the argument against untargeted screening. Levis and colleagues' individual-participant meta-analysis showed that cutoff-based estimates in the literature had been systematically inflated by selective reporting. Somatic items overlap with physical illness, inflating scores in medically ill populations. The PHQ-9 also compresses nine heterogeneous symptoms into one number, so identical totals can describe very different clinical pictures.
Key Publications
- Spitzer, R. L., Kroenke, K. & Williams, J. B. W.. (1999). Validation and utility of a self-report version of PRIME-MD: The PHQ Primary Care Study. 10.1001/jama.282.18.1737
- Kroenke, K., Spitzer, R. L. & Williams, J. B. W.. (2001). The PHQ-9: Validity of a brief depression severity measure. 10.1046/j.1525-1497.2001.016009606.x
- Levis, B., Benedetti, A. & Thombs, B. D.. (2019). Accuracy of the PHQ-9 for screening to detect major depression: Individual participant data meta-analysis. 10.1136/bmj.l1476