What are the PHQ‑9 scoring thresholds and how should the scores be interpreted and applied in clinical practice for diagnosing and monitoring depression?

PHQ-9 Scoring Thresholds and Clinical Application

Standard Score Interpretation and Action Thresholds

The PHQ-9 uses five severity categories with specific cutoff scores that dictate clinical management: scores 1-7 indicate minimal/mild symptoms requiring education and monitoring only; scores 8-14 indicate moderate symptoms requiring consultation with psychology or psychiatry for diagnostic confirmation; scores 15-19 indicate moderately severe symptoms requiring immediate mental health referral; and scores 20-27 indicate severe symptoms requiring immediate mental health referral. 1, 2

Detailed Score Ranges and Clinical Actions

• Scores 0-4 (None): No depressive symptoms detected; no further screening needed 1

• Scores 5-7 (Minimal/Mild): Patient demonstrates minimal symptoms with effective coping skills and adequate social support 1, 2. Provide education about depression and normal stress responses, verify coping resources, identify risk factors for depression, and schedule reassessment at 3,6, and 12 months or during major life transitions 2, 3. Do not initiate antidepressant medication or formal psychotherapy, as this represents overtreatment of mild symptoms that typically respond to supportive care 2

• Scores 8-14 (Moderate): Patient exhibits subthreshold to moderate depressive symptoms with mild-to-moderate functional impairment 1, 3. Mandatory consultation with psychology or psychiatry for diagnostic confirmation is required 1, 2. Determine associated sociodemographic factors, psychiatric or health comorbidities, duration of symptoms, and degree of functional impairment 3. Consider either pharmacologic treatment or structured psychological therapy (individually guided self-help based on cognitive behavioral therapy with behavioral activation, or structured physical activity programs) 3

• Scores 15-19 (Moderately Severe) and 20-27 (Severe): Patient has most depressive symptoms with moderate-to-marked functional interference 1, 2. Immediate referral to psychology and/or psychiatry for formal diagnosis and high-intensity treatment is mandatory 1, 2

Two-Stage Screening Approach

Begin with the PHQ-2 (first two items: anhedonia and depressed mood), which has 73.7% sensitivity and 75.2% specificity for major depressive disorder 4, 5. Each item is scored 0-3 based on frequency over the past 2 weeks (0="not at all," 1="several days," 2="more than half the days," 3="nearly every day") 1

• PHQ-2 score 0-1: No further screening needed 1, 4
• PHQ-2 score 2-3: Proceed to complete the full PHQ-9 (remaining 7 items assess sleep problems, low energy, appetite changes, low self-view, concentration difficulties, motor retardation or agitation, and thoughts of self-harm) 1, 4

This two-stage approach reduces the number of patients needing the full PHQ-9 by 57% while maintaining sensitivity of 82% and specificity of 87% for detecting major depression 5

Critical Safety Override: Item 9 Assessment

Any endorsement of thoughts about being better off dead or hurting oneself (Item 9) mandates immediate referral for emergency psychiatric evaluation by a licensed mental health professional, regardless of the total PHQ-9 score 1, 2, 3, 4. While awaiting evaluation, facilitate a safe environment, arrange one-to-one observation, and remove access to lethal means 2, 4

Never omit Item 9 from the assessment, as doing so artificially lowers the total score, weakens predictive validity, and may lead to under-recognition of acute suicide risk even when total scores are low 1, 2, 3. Patients do not typically endorse self-harm exclusively but rather in combination with other symptoms 1

Optimal Cutoff Score Considerations

The traditional cutoff of ≥10 has 88% sensitivity and 88% specificity for major depression in general populations 6, 7. However, a lower cutoff of ≥8 is supported by meta-analysis and improves sensitivity in cancer outpatients without substantially compromising specificity 1, 7. Cutoff scores between 8-11 show no substantial differences in pooled sensitivity and specificity 7

The full PHQ-9 demonstrates 89.5% sensitivity and 77.5% specificity at a cutoff of 11 4, with acceptable diagnostic properties across the 8-11 range 7

Monitoring Treatment Response

Repeat PHQ-9 administration at 3,6, and 12 months after treatment initiation allows early detection of inadequate response or relapse 4. A decrease of 5 points represents the minimal clinically important difference indicating meaningful improvement 4. The PHQ-9 demonstrates strong sensitivity to change, with effect sizes of -1.33 for improved depression status, -0.21 for unchanged status, and 0.47 for deteriorated status 8

Persistent moderate scores (8-14) after 4-6 weeks of treatment indicate need for dose optimization or treatment modification 4

Special Populations and Cultural Considerations

Use culturally sensitive assessments when possible, and tailor evaluation for patients with learning disabilities or cognitive impairments 1, 3. In cancer patients specifically, screen at initial diagnosis/start of treatment, at regular intervals during treatment, at 3,6, and 12 months after treatment, at diagnosis of recurrence or progression, when approaching death, and during times of personal transition or family crisis 1

Risk Factors Requiring Immediate Referral Despite Moderate Scores

Even with PHQ-9 scores of 8-14, immediate psychiatry referral is warranted if any of the following are present: prior mood disorder (treated or untreated), co-occurring mood or anxiety disorder, current or past substance-use disorder, recurrent/advanced/progressive cancer, social isolation (single, widowed, divorced), unemployment with limited financial resources, or low educational attainment 2

Common Pitfalls to Avoid

• Never screen without established protocols for managing positive screens, as screening alone without intervention pathways does not improve outcomes 4
• Do not fail to complete the full PHQ-9 if the initial PHQ-2 screen is positive (score ≥2) 3
• Recognize that false-positive rates reach 60-76% in primary care settings where depression prevalence is 5-10%, meaning positive screens require diagnostic confirmation rather than automatic treatment initiation 4
• Screen for bipolar disorder before initiating or increasing antidepressants in patients with elevated PHQ-9 scores, as undiagnosed bipolar disorder can lead to manic episodes, rapid cycling, or mixed states when treated with antidepressants alone 4
• Do not underestimate the severity of a score of 12—this represents clinically significant depression requiring active treatment, not just "watchful waiting" 3