How is the Patient Health Questionnaire (PHQ) 9 score interpreted and what are the treatment options based on the score?

PHQ-9 Scoring and Interpretation

The PHQ-9 is scored from 0-27 by summing responses to 9 items (each rated 0-3), with a score of ≥10 representing the optimal threshold for detecting major depression, demonstrating 88% sensitivity and specificity in validation studies. 1

Score Interpretation and Depression Severity Categories

The PHQ-9 categorizes depression severity into distinct ranges that guide clinical decision-making:

• Score 0-4: Minimal or no depression - no intervention typically needed 2
• Score 5-9: Mild depression - watchful waiting, support, and reassessment 1
• Score 10-14: Moderate depression - active treatment warranted 2, 1
• Score 15-19: Moderately severe depression - requires mental health referral 2, 1
• Score 20-27: Severe depression - urgent mental health referral needed 2, 1

A cutoff score of ≥10 is recommended across clinical settings based on meta-analytic data, with pooled sensitivity of 0.78 and specificity of 0.87. 3 This threshold performs consistently well whether in primary care, obstetrics-gynecology, or stroke populations. 1, 4

Screening Approach

Use a phased screening strategy starting with the first two PHQ-9 items (anhedonia and depressed mood), and only complete the full 9-item questionnaire if either item scores ≥2. 5, 2

The two screening questions assess:

1. Little interest or pleasure in doing things (anhedonia)
2. Feeling down, depressed, or helpless (depressed mood)

If both items score 0-1, the screen is negative and no further assessment is needed. 5

Critical Safety Assessment

Never omit item 9 regarding self-harm thoughts - this artificially lowers scores and misses critical risk information. 5, 2 If any self-harm ideation is endorsed, immediate referral for emergency psychiatric evaluation is required regardless of total PHQ-9 score. 5, 6

Treatment Recommendations Based on Score

Scores 1-7 (Minimal Symptoms)

• No formal intervention required 5, 2
• Patients typically have effective coping skills and adequate social support 5
• Consider reassessment if clinical situation changes

Scores 8-14 (Moderate Depression)

Initiate low-intensity interventions including: 5, 2

• Individually guided self-help based on cognitive behavioral therapy (CBT) with behavioral activation and problem-solving 5
• Group-based CBT for depression 5
• Structured physical activity programs 5
• Consider pharmacologic treatment as appropriate 5
• Seek consultation with psychology or psychiatry for diagnostic confirmation 5, 2

Patients in this range have subthreshold depressive symptoms with mild to moderate functional impairment. 5, 2

Scores 15-27 (Moderately Severe to Severe Depression)

Immediate referral to psychology and/or psychiatry for formal diagnosis and treatment is mandatory. 5, 2, 6 These patients have most depressive symptoms that interfere moderately to markedly with functioning. 5, 2

High-intensity interventions delivered by licensed mental health professionals are required, including: 5, 2, 6

• Individual psychological therapy using evidence-based treatment manuals 5, 6
• Cognitive behavioral therapy with cognitive change and behavioral activation 5, 6
• Biobehavioral strategies, education, and relaxation techniques 5, 6
• Relapse prevention components 5
• Behavioral couples therapy if relationship issues contribute to depression 5, 6
• Monitor treatment efficacy with repeated PHQ-9 assessments 6

Special Considerations and Common Pitfalls

The PHQ-9 loses accuracy in patients with cognitive impairment - use alternative assessment methods in this population. 5 Consider informant-based tools like the AD8 when cognitive deficits are present. 5

Use culturally sensitive assessments when possible and tailor evaluation for patients with learning disabilities or cognitive impairments. 5, 2

Be aware that detecting depression in older adults is particularly challenging and may require additional clinical judgment. 5

Do not fail to complete the full PHQ-9 when initial screening items (questions 1-2) suggest depression. 2 This is a common error that results in missed diagnoses.

Timing of Screening

Administer the PHQ-9 at: 5

• Initial diagnosis or start of treatment
• Regular intervals during treatment
• 3,6, and 12 months after treatment completion
• Diagnosis of disease recurrence or progression
• Times of personal transition or family crisis
• When approaching end of life in palliative care settings 5