PHQ-9 Patient Health Questionnaire 9-Item Depression Module
This tool implements the standard 9-item Patient Health Questionnaire depression module (PHQ-9), the most widely used and extensively validated brief instrument for screening, diagnosing, monitoring, and measuring the severity of depression in primary care, specialty mental health, and community settings. Originally published by Kroenke K, Spitzer RL, and Williams JBW in 2001 in the Journal of General Internal Medicine (16:606-613) with development sponsorship from Pfizer Inc., the PHQ-9 operationalizes the nine DSM-IV (and subsequent DSM-5) diagnostic criterion symptoms of a major depressive episode over a past two weeks recall window. Each of the nine core items uses a common four-point frequency response scale (0 = Not at all through 3 = Nearly every day). No items are reverse-keyed; all nine items contribute directly to the total score, yielding a closed 0-27 range with higher values uniformly indicating greater self-reported depressive symptom burden. The standard five-tier developer-recommended severity classification is applied: None-Minimal (0-4), Mild (5-9), Moderate (10-14), Moderately Severe (15-19), and Severe (20-27). The widely adopted ≥10 screening cutoff corresponds, in the original 2001 primary care validation sample, to a documented sensitivity of 88% and specificity of 88% for major depressive disorder relative to structured diagnostic interview. An optional tenth item (Q10) assessing the functional difficulty or impairment associated with any endorsed problems is also administered; per standard PHQ-9 scoring convention, Q10 is reported separately and is NOT included in the 0-27 severity total. The ninth item (Q9), which assesses self-harm ideation and passive death wishes, is also highlighted separately in the results section because any non-zero response on Q9 is recognized in the published PHQ-9 scoring guidance as a clinically significant indicator that warrants immediate attention — though, as with all PHQ-9 output, it is presented here for informational reference only and does not constitute a clinical assessment.
PHQ-9 Assessment — Past Two Weeks
Symptom absent during the past two weeks
Present on some days but less than half the time
Present on a majority of days in the two-week window
Present on almost all or all days
Symptom absent during the past two weeks
Present on some days but less than half the time
Present on a majority of days in the two-week window
Present on almost all or all days
Symptom absent during the past two weeks
Present on some days but less than half the time
Present on a majority of days in the two-week window
Present on almost all or all days
Symptom absent during the past two weeks
Present on some days but less than half the time
Present on a majority of days in the two-week window
Present on almost all or all days
Symptom absent during the past two weeks
Present on some days but less than half the time
Present on a majority of days in the two-week window
Present on almost all or all days
Symptom absent during the past two weeks
Present on some days but less than half the time
Present on a majority of days in the two-week window
Present on almost all or all days
Symptom absent during the past two weeks
Present on some days but less than half the time
Present on a majority of days in the two-week window
Present on almost all or all days
Symptom absent during the past two weeks
Present on some days but less than half the time
Present on a majority of days in the two-week window
Present on almost all or all days
No such thoughts during the past two weeks
Present on some days but less than half the time
Present on a majority of days in the two-week window
Present on almost all or all days
No meaningful functional impairment
Mild to moderate functional interference
Substantial functional interference across multiple areas
Severe impairment rendering major areas of function unmanageable
PHQ-9 Instrument: Scoring, Severity Tiers, Validation, and Q9 Self-Harm Item
Item Content and Coverage of DSM Depressive Episode Criteria
The PHQ-9 is unique among brief depression screening instruments in that each of its nine core items corresponds directly to one of the nine DSM-IV (and subsequently DSM-5) diagnostic criterion symptoms required for the formal diagnosis of a major depressive episode. Specifically: (Q1) loss of interest or pleasure in most activities (anhedonia, criterion A1); (Q2) depressed mood most of the day, nearly every day (criterion A2); (Q3) insomnia or hypersomnia nearly every day (criterion A4); (Q4) fatigue or loss of energy nearly every day (criterion A5); (Q5) significant weight loss when not dieting, weight gain, or decrease or increase in appetite nearly every day (criterion A3); (Q6) feelings of worthlessness or excessive or inappropriate guilt nearly every day (criterion A6); (Q7) diminished ability to think or concentrate, or indecisiveness, nearly every day (criterion A7); (Q8) psychomotor agitation or retardation nearly every day, observable by others (criterion A8); and (Q9) recurrent thoughts of death, recurrent suicidal ideation without a specific plan, or a suicide attempt or specific plan for committing suicide (criterion A9). All nine items share a common two-week retrospective recall window and a common four-point frequency response scale with anchors 0 = Not at all, 1 = Several days, 2 = More than half the days, and 3 = Nearly every day. None of the nine items are reverse-keyed; all are scored in the same forward direction so that higher response values uniformly reflect greater symptom frequency or severity.
Scoring Algorithm, Five-Tier Severity Classification, and the ≥10 Cutoff (Sensitivity 88%, Specificity 88%)
Because all nine PHQ-9 core items are scored directly with no reverse transformations required, the severity scoring algorithm is straightforward. For each core item i (i = 1 … 9) with raw response ri ∈ {0, 1, 2, 3}, the scored contribution si equals ri. The total PHQ-9 severity score is the arithmetic sum across the nine core items: Total = Σ si for i = 1 … 9. Since each item contributes between 0 and 3 points, the closed theoretical range of the total PHQ-9 severity score is [0, 27], with a population midpoint of 13.5 under a uniform distribution and an empirical community sample mean typically reported between approximately 4 and 6. The standard five-tier developer-endorsed severity classification, as published in the original 2001 validation paper and adopted by the American Psychiatric Association, National Institute of Mental Health, and most major guidelines worldwide, partitions the 0-27 range as follows: (1) None-Minimal depression severity, scores 0 through 4; (2) Mild depression severity, scores 5 through 9; (3) Moderate depression severity, scores 10 through 14; (4) Moderately Severe depression severity, scores 15 through 19; and (5) Severe depression severity, scores 20 through 27. The cutoff score of 10 or greater is the most widely used and recommended threshold for identifying probable cases of major depressive disorder warranting further evaluation. In the original 2001 Kroenke, Spitzer & Williams validation study, which enrolled 3,000 adult primary care patients from eight geographically diverse U.S. primary care clinics and used the Structured Clinical Interview for DSM-IV (SCID) administered by mental health professionals as the independent gold-standard reference, a PHQ-9 score of ≥10 demonstrated a sensitivity of 88% (88% of patients with SCID-confirmed major depressive disorder scored ≥10) and a specificity of 88% (88% of patients without SCID-confirmed major depressive disorder scored below 10). These symmetric, balanced operating characteristics explain why the ≥10 threshold has become the de facto standard screening cutoff in primary care globally. As with all psychometric screening instruments, these sensitivity and specificity values are population-level descriptors; individual performance may vary, and the five severity tiers are descriptive interpretive labels, not diagnostic boundaries.
Optional Q10 Functional Difficulty Item and Q9 Self-Harm / Suicidal Ideation Item Significance
The PHQ-9 administration format commonly includes a tenth, optional question (Q10) that asks: "If you checked off any problems, 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?" with four response options: Not difficult, Somewhat difficult, Very difficult, and Extremely difficult. Per explicit PHQ-9 scoring convention, this Q10 functional difficulty item is NEVER included in the 0-27 severity total; it is always reported separately, as implemented on this page, as an indicator of functional impairment or distress attributable to the endorsed symptoms, not as a contributor to symptom severity scoring. Separately, the ninth core item (Q9) — which assesses "thoughts that you would be better off dead or of hurting yourself in some way" — carries special clinical significance regardless of the total PHQ-9 score. Per published PHQ-9 scoring guidance and standard clinical convention, ANY non-zero response on Q9 (i.e., a response of "Several days," "More than half the days," or "Nearly every day") is considered a clinically significant indicator that warrants immediate attention and safety evaluation by a qualified clinician, irrespective of the total PHQ-9 severity score or classification tier. As emphasized repeatedly throughout this page, however, this is a neutral, descriptive statement of published scoring convention only; it is NOT a clinical assessment, and any user with any concerns about Q9 content, self-harm thoughts, passive death wishes, hopelessness, or personal safety must seek immediate contact with a qualified mental health professional, crisis hotline, or emergency services without delay.
Public Domain Status, Pfizer Development Sponsorship, and Permitted Use
The PHQ-9 Patient Health Questionnaire 9-item depression module was developed by Drs. Kurt Kroenke, Robert L. Spitzer, and Janet B. W. Williams as part of the larger Patient Health Questionnaire (PHQ) suite of instruments, which grew out of the earlier Primary Care Evaluation of Mental Disorders (PRIME-MD) research program. Development of the PHQ suite, including the PHQ-9, was supported by Pfizer Inc. through an unrestricted educational and research grant to the principal investigators. In a long-standing and widely publicized official policy jointly confirmed by the instrument developers and Pfizer Inc., the entire Patient Health Questionnaire suite — including the PHQ-9 depression module, the GAD-7 anxiety module, the PHQ-15 somatic symptom module, and related instruments — is explicitly designated a publicly available instrument and placed in the public domain. No written permission, license, royalty, or fee of any kind is required to reproduce, administer, translate, culturally adapt, modify appropriately, or use the PHQ-9 for any lawful purpose including clinical practice, clinical documentation, public health screening, research (commercial and non-commercial), education, commercial software implementation, electronic health record integration, mobile health applications, and web-based screening platforms. The only customary expectations, consistent with standard academic practice, are (1) appropriate citation of the original 2001 Kroenke, Spitzer & Williams Journal of General Internal Medicine publication when formally reporting PHQ-9-derived results in written, regulatory, or research contexts, and (2) avoidance of labeling substantially modified, paraphrased, or construct-altered versions of the instrument as the PHQ-9 without appropriate qualification. The historical Pfizer Inc. sponsorship of the original development research is solely an acknowledgement of funding source and does not impose any ongoing licensing, usage, or royalty restrictions on the instrument.
| PHQ-9 Score Range | Severity Tier | Interpretive Reference |
|---|---|---|
| 0 – 4 | None-Minimal Depression | Few or no depressive symptoms endorsed over the past two weeks; symptom burden consistent with the lower end of the general population distribution. |
| 5 – 9 | Mild Depression | Subthreshold depressive symptoms present on several days; common during situational stress, grief, or life transitions. Standard guidance typically includes watchful waiting, supportive self-care strategies, and repeat screening in 2-4 weeks. |
| 10 – 14 | Moderate Depression | Symptoms present on more than half the days across multiple domains; reaches the widely used ≥10 screening cutoff with published sensitivity 88% / specificity 88%. Generally warrants further evaluation and discussion of treatment options per standard clinical guidelines. |
| 15 – 19 | Moderately Severe Depression | High frequency of depressive symptoms across multiple criterion domains; typically associated with at least moderate functional impairment. Formal evaluation by a qualified mental health professional is strongly recommended; evidence-based treatment (psychotherapy, pharmacotherapy, or combined) is usually indicated. |
| 20 – 27 | Severe Depression | Very high symptom burden across most or all nine criterion domains, typically present nearly every day; strongly associated with substantial functional impairment across work, relationships, and self-care. Urgent formal evaluation by a qualified mental health professional is indicated. If accompanied by any Q9 self-harm ideation, immediate safety evaluation is essential. |
Data Source and References
- [1] Kroenke K, Spitzer RL, Williams JBW (2001). The PHQ-9: Validity of a brief depression severity measure. Journal of General Internal Medicine, 16(9):606-613. doi.org — Original PHQ-9 development and primary care validation study; SCID reference standard; ≥10 cutoff sensitivity / specificity 88% reported; Pfizer Inc. development grant support acknowledged.
- [2] Kroenke K, Spitzer RL, Williams JBW, Löwe B (2010). The Patient Health Questionnaire Somatic, Anxiety, and Depressive Symptom Scales: A systematic review. General Hospital Psychiatry, 32(4):345-359. — Comprehensive systematic review of PHQ-9 (and PHQ/GAD suite) psychometric properties, validity, and clinical utility across diverse populations, languages, and settings.
- [3] Pfizer Inc. / Patient Health Questionnaire (PHQ) official public-use statement. — The PHQ-9 and the complete Patient Health Questionnaire suite are designated publicly available instruments free for use at no cost. No written permission, license, royalty, or fee is required for clinical, research, educational, or commercial use, including electronic, software, and mobile health implementations.
Frequently Asked Questions
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No. The PHQ-9 Patient Health Questionnaire 9-item depression module is a validated psychometric screening and severity-monitoring instrument, not a diagnostic tool. It does not and cannot establish the presence of major depressive disorder, persistent depressive disorder (dysthymia), bipolar disorder, adjustment disorder with depressed mood, or any other psychiatric or medical diagnosis. The PHQ-9 was designed to screen for the presence and severity of depressive symptoms and to support — not replace — clinical decision-making. Elevated PHQ-9 scores may indicate a level of depressive symptomatology that warrants further evaluation, but a PHQ-9 score by itself is never sufficient to make any diagnosis. All diagnostic decisions and treatment recommendations must be made by a qualified psychiatrist, licensed clinical psychologist, or other appropriately trained mental health or healthcare professional following a formal clinical evaluation.
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The PHQ-9 consists of nine core depressive symptom items (Q1 through Q9) each using an identical four-point frequency response scale anchored to the past two weeks: 0 = Not at all, 1 = Several days, 2 = More than half the days, and 3 = Nearly every day. None of the nine items are reverse-keyed; all nine are scored in the same forward direction so that higher response values uniformly reflect greater symptom frequency or severity. The total PHQ-9 severity score is the simple arithmetic sum of Q1 through Q9, yielding a closed theoretical range of 0 to 27. The optional tenth question (Q10) — which asks about the functional difficulty or impairment caused by any endorsed problems — is intentionally NOT included in the total severity score and is reported separately, as specified by the original PHQ-9 developers and consistent with all published scoring guidelines. Q10 serves as a descriptive indicator of functional impact rather than a contributor to the symptom-severity total.
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The PHQ-9 cutoff score of 10 or greater is the most widely recommended threshold for identifying probable cases of major depressive disorder that warrant further clinical evaluation. In the original 2001 validation study by Kroenke, Spitzer, and Williams published in the Journal of General Internal Medicine, which enrolled 3,000 primary care patients across eight U.S. primary care clinics and used the structured Structured Clinical Interview for DSM-IV (SCID) as the independent gold-standard diagnostic reference, a PHQ-9 score of ≥10 demonstrated a sensitivity of 88% — meaning that 88% of participants who met formal diagnostic criteria for major depressive disorder by SCID interview scored at or above 10 — and a specificity of 88% — meaning that 88% of participants who did not meet criteria for major depressive disorder scored below 10. These balanced, symmetric performance characteristics are one reason the ≥10 threshold has become the de facto standard screening cutoff in primary care and research settings worldwide. The standard five-tier severity classification recommended by the developers partitions the 0-27 score range as follows: None-Minimal severity (scores 0-4), Mild severity (scores 5-9), Moderate severity (scores 10-14), Moderately Severe severity (scores 15-19), and Severe severity (scores 20-27). As with all screening instruments, the sensitivity and specificity values are population-level descriptors derived from the specific validation sample, and the five severity tiers are descriptive interpretive labels rather than diagnostic boundaries.
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Yes, the PHQ-9 (and the full Patient Health Questionnaire suite) is explicitly designated a publicly available instrument and placed in the public domain by the developers and the original sponsor, Pfizer Inc. The PHQ-9 was developed by Drs. Kurt Kroenke, Robert L. Spitzer, and Janet B. W. Williams with financial support from Pfizer Inc. as part of the broader Primary Care Evaluation of Mental Disorders (PRIME-MD) and Patient Health Questionnaire research program. Following the long-standing official policy established by Pfizer and the instrument developers, no written permission, license, royalty, or fee is required to reproduce, administer, translate, adapt, or use the PHQ-9 for any lawful purpose including: clinical practice and documentation, research studies (commercial and non-commercial), educational use, commercial software and electronic health record integration, mobile health application implementation, and web-based screening tools. The standard academic convention applies: users are requested to cite the original 2001 Kroenke, Spitzer & Williams publication in the Journal of General Internal Medicine when formally reporting PHQ-9 results, and to avoid labeling substantially modified versions of the instrument as the PHQ-9. The Pfizer sponsorship of the original development work is a historical acknowledgement and does not impose any ongoing restrictions, licensing requirements, or usage limitations on the instrument itself.