PHQ-9: Patient Health Questionnaire-9

Foundational Context

The PHQ-9 was developed by Drs. Robert L. Spitzer, Janet B.W. Williams, and Kurt Kroenke (2001) as a brief yet clinically robust measure of depression severity. Its direct correspondence to DSM diagnostic criteria allows clinicians to rapidly identify symptoms consistent with major depressive disorder while also capturing functional impact.

It is widely used in primary care, specialty mental health, and research for initial screening, monitoring treatment response, and supporting measurement-based care.

What the Assessment Measures

The PHQ-9 captures symptoms of depression experienced over the past two weeks, including:

• Anhedonia (little interest or pleasure)
• Depressed mood
• Sleep disturbances
• Fatigue or low energy
• Appetite changes
• Feelings of worthlessness or guilt
• Concentration difficulties
• Psychomotor changes (moving slowly or being fidgety)
• Thoughts of death or self-harm (Item 9)

Interpretation Guidelines

The PHQ-9 produces a total score between 0–27.

Severity Thresholds:

• 0–4: Minimal/None. No action typically required.
• 5–9: Mild. Watchful waiting; repeat at follow-up.
• 10–14: Moderate. Treatment plan: counseling, follow-up, or pharmacotherapy.
• 15–19: Moderately Severe. Active treatment with pharmacotherapy and/or psychotherapy.
• 20–27: Severe. Immediate treatment; consider referral to specialty care.

Clinical Threshold:

• ≥10 has 88% sensitivity and specificity for major depression.

Item 9 (Suicidal Ideation):

• Any score ≥1 requires immediate clinical follow-up and safety assessment, regardless of total score.

Administration Considerations

1. Self-Report: Patients rate symptoms over the past 2 weeks.
2. Time: Takes 2–5 minutes.
3. Scoring: Sum the values for all 9 items (0 = not at all, 3 = nearly every day).
4. Monitoring: Typically administered at intake and every 2–4 weeks during treatment. A decrease of 5 points or more is clinically significant.

Psychometric Properties

• Reliability: High internal consistency (α = 0.89) and test-retest reliability (r = 0.84).
• Validity: 88% sensitivity/specificity for major depression at cutoff ≥10.
• Responsive: Highly sensitive to change over time, making it ideal for treatment monitoring.

Limitations

• Screening, Not Diagnosis: A full clinical evaluation is required for full clinical evaluation.
• Somatic Overlap: Symptoms like fatigue or sleep changes may overlap with physical illnesses.
• Recall Bias: Depends on accurate patient recall of the past 2 weeks.

References

Kroenke, K., Spitzer, R. L., & Williams, J. B. (2001). The PHQ-9: validity of a brief depression severity measure. Journal of General Internal Medicine, 16(9), 606-613.

Additional Context

The Patient Health Questionnaire-9 (PHQ-9) is a validated, 9-item self-report measure that assesses depression severity. Widely used in clinical practice for screening, monitoring treatment response, and supporting measurement-based care.

Why the PHQ-9 Matters in Practice

A 34-year-old patient presents to primary care with persistent fatigue and difficulty sleeping. Rather than relying on subjective assessment alone, administering the PHQ-9 reveals a score of 16 (moderately severe depression),quantifying symptoms that might otherwise go undetected or undertreated.

What is the PHQ-9?

The Patient Health Questionnaire-9 (PHQ-9) is a multipurpose scale for screening, monitoring, and measuring the severity of depression to support clinical evaluation. Developed by Drs. Robert L. Spitzer, Janet B.W. Williams, Kurt Kroenke, and colleagues, the PHQ-9 incorporates DSM-IV depression diagnostic criteria with other leading major depressive symptoms into a brief self-report tool.

The PHQ-9 is the nine-item depression module from the full Patient Health Questionnaire. It asks patients to rate how often they've been bothered by specific problems over the past two weeks, including anhedonia, depressed mood, sleep disturbances, fatigue, appetite changes, guilt, concentration difficulties, psychomotor issues, and suicidal ideation.

Each item is scored from 0 (not at all) to 3 (nearly every day), yielding a total score range of 0-27. The PHQ-9 has demonstrated excellent reliability and validity across diverse populations and clinical settings, making it one of the most widely used depression screening tools worldwide.

Screening vs. Diagnosis

The PHQ-9 is a screening and monitoring tool that identifies individuals who may benefit from further evaluation. While a score ≥10 has good sensitivity and specificity for major depression, a full clinical evaluation by a qualified professional is required for full clinical evaluation.

PHQ-9 in Clinical Practice

Used in primary care, specialty mental health, hospitals, and community settings for initial assessment, treatment monitoring, and outcome measurement.

How to Administer the PHQ-9

Self-Report Format

Patients complete the questionnaire independently, rating how often they've experienced each symptom over the past 2 weeks. Can be completed on paper or digitally.

Quick Administration

Takes 2-5 minutes to complete. Scoring is automated and straightforward, simply sum the values for all nine items.

Regular Monitoring

Typically administered at intake, then periodically throughout treatment (e.g., every 2-4 weeks) to track symptom changes and treatment response.

Suicide Risk Assessment

Item 9 specifically asks about suicidal thoughts. Any positive response requires immediate clinical follow-up and safety assessment.

Best Practices

• Ensure patients understand they're rating symptoms over the past 2 weeks
• Review responses with the patient, particularly item 9 (suicidal ideation)
• Consider cultural and linguistic factors, validated translations available in 30+ languages
• Integrate scores with clinical judgment, don't rely solely on numbers

PHQ-9 Scoring & Interpretation

What is a Good PHQ-9 Score?

A "good" PHQ-9 score is 0-4, indicating minimal or no depression symptoms. Scores in this range suggest that depressive symptoms are not significantly impacting daily functioning, and no clinical intervention is typically needed.

Minimal to no depression. This is the target range for successful treatment outcomes and healthy individuals.

In treatment monitoring, achieving a score below 5 is often considered clinical remission from depression.

However, context matters. For someone currently in treatment for depression, a score of 5-9 (mild depression) might represent significant improvement from an initial score of 20 (severe depression). In this case, the trajectory is more important than the absolute number.

Important: A single "good" score doesn't tell the whole story. Trends over time, functional impairment, and individual patient context are equally important in clinical decision-making.

Try the Interactive PHQ-9 Assessment

Get automated scoring and clinical interpretation. Answer 9 questions and review your depression severity score.

Score Ranges Explained

Monitoring Treatment Response

A decrease of 5 points or more is considered a clinically significant improvement. Track changes over time to assess treatment effectiveness.

If scores aren't improving after 4-6 weeks of treatment, consider adjusting the treatment plan, increasing intervention intensity, or seeking consultation.

Diagnostic Considerations

A score of 10 or greater has 88% sensitivity and 88% specificity for major depression. However, the PHQ-9 is a screening tool, not a substitute for clinical diagnosis.

Always conduct a full clinical evaluation before making treatment decisions based on PHQ-9 scores.

Critical: Item 9 Assessment

Any score ≥1 on item 9 (suicidal thoughts) requires immediate safety evaluation and appropriate intervention, regardless of total PHQ-9 score.

Treatment Recommendations by Score

PHQ-9 scores guide intervention intensity, but clinical judgment remains essential. These are evidence-based starting points, not rigid protocols.

Minimal/None

Action: No treatment indicated. Consider reassessment in 6-12 months or if symptoms emerge. Provide psychoeducation on depression warning signs.

Mild Depression

Action: Watchful waiting with reassessment in 2-4 weeks. Consider behavioral interventions (exercise, sleep hygiene, stress management).

If symptoms persist or worsen, initiate treatment. Patient preference for counseling or medication should guide intervention.

Moderate Depression

Action: Active treatment recommended. Options include psychotherapy (CBT, IPT), antidepressant medication, or combination therapy.

Reassess in 4-6 weeks. If no improvement, consider treatment intensification or psychiatric consultation.

Moderately Severe Depression

Action: Immediate initiation of combination therapy (medication + psychotherapy). Consider psychiatric referral if no prior specialty care.

Weekly follow-up for first 4 weeks. Reassess suicide risk at each visit. Treatment resistance may require medication adjustment or ECT consideration.

Severe Depression

Action: Urgent psychiatric consultation. Combination therapy mandatory. Assess for inpatient hospitalization if safety concerns, psychotic features, or treatment resistance.

Consider intensive outpatient programs (IOP), partial hospitalization (PHP), or ECT for treatment-resistant cases. Daily to weekly monitoring until stabilized.

Remember: PHQ-9 scores are one data point. Integrate with patient history, functional impairment, comorbidities, and clinical presentation. A patient with a moderate score but severe functional impairment may require more intensive treatment than scores alone suggest.

PHQ-9 Psychometric Properties

Validity

• 88% sensitivity for major depression at cutoff ≥10
• 88% specificity for major depression at cutoff ≥10
• 81.4% sensitivity / 89.6% specificity (Kocalevent et al., 2013 community sample)
• 92.2% positive predictive value for major depression

Reliability

• α = 0.89 Cronbach's alpha (high internal consistency)
• r = 0.84 test-retest reliability (Kroenke et al., 2001)
• ≥5 pts clinically significant change threshold
• 13+ validated age range (adolescents to older adults)

Population Context

Documenting PHQ-9 scores in clinical notes?

PHQ-9 scores go in the Objective section, with severity classification and score change from last session. See our SOAP notes guide, progress notes guide, and intake notes guide.

Clinical Use Cases

Initial Screening

Used in primary care, emergency departments, and specialty settings to identify patients who may have depression and require further evaluation.

Treatment Monitoring

Serial administration tracks symptom changes over time, helping clinicians assess whether interventions are effective or need adjustment.

Research & Outcomes

Widely used in clinical trials and quality improvement initiatives to measure depression severity and track population-level outcomes.

Collaborative Care

Enables shared decision-making between patients and providers by providing objective data on symptom patterns and treatment progress.

Chronic Disease Management

Screens for depression in patients with chronic medical conditions (diabetes, heart disease, cancer) where depression is common and impacts outcomes.

Value-Based Care

Supports quality metrics for depression screening and treatment response required by HEDIS, PCMH, and other quality reporting frameworks.

PHQ-9 in HiBoop

Automated scoring, trend tracking, and clinical insights, all built into your workflow

Automated Scoring

Instant calculation of total scores and severity classification. No manual math, results are ready the moment patients complete the assessment.

• Real-time severity classification
• Automatic flagging of item 9 responses
• Historical score comparison

Visual Trend Tracking

See depression severity over time with clear, clinician-friendly graphs. Identify patterns, plateaus, and treatment response at a glance.

• Longitudinal score visualization
• Clinically significant change indicators
• Multi-scale comparison (PHQ-9, GAD-7, etc.)

Smart Alerts

Automatic notifications when scores indicate suicide risk, severe symptoms, or lack of improvement guide timely clinical action.

• Suicide risk alerts (item 9)
• Severe symptom notifications
• Treatment plateau indicators

Patient Engagement

Patients complete assessments on their phone, tablet, or computer, before appointments or between sessions, improving data collection and engagement.

• Digital self-administration
• Secure patient portals
• Results shared with patients

Use the PHQ-9 in Your Practice

HiBoop automates PHQ-9 administration, scoring, and longitudinal tracking, so clinicians spend less time on paperwork and more time with patients.

PHQ-9 vs Other Depression & Anxiety Scales

Choosing the right assessment tool depends on your clinical goals. Here's how the PHQ-9 compares to other widely-used mental health screening tools.

PHQ-9 vs GAD-7: Depression vs Anxiety

Clinical Tip: Use both PHQ-9 and GAD-7 together for thorough mental health screening. Studies show 40-50% of patients with depression also have anxiety symptoms, and vice versa.

PHQ-9 vs BDI-II: Brief vs Detailed Depression Assessment

When to Choose PHQ-9: Primary care settings, population screening, and when you need a free, quick assessment that aligns with DSM-5-TR. BDI-II provides more granular symptom detail for specialty mental health settings.

PHQ-9 vs PHQ-2: Full Screen vs Ultra-Brief Screen

Two-Stage Screening: Many practices use PHQ-2 for universal screening, then administer the full PHQ-9 only to those who screen positive (score ≥3). This reduces burden while maintaining sensitivity.

Quick Selection Guide

Primary Care

Use PHQ-9 + GAD-7 for thorough mental health screening

Time-Constrained

Start with PHQ-2, follow up with full PHQ-9 if positive

Specialty Mental Health

PHQ-9 for routine monitoring, BDI-II for detailed assessment