Patient Health Questionnaire-2 (PHQ-2)

Purpose and Clinical Application

The PHQ-2 is an ultra-brief screening tool derived from the PHQ-9, designed to quickly identify individuals who may have major depression. It consists of the two core items from the PHQ-9 that assess the most fundamental symptoms of depression, making it ideal for rapid screening in busy clinical settings.

Clinical Significance

The PHQ-2 serves as an efficient first-line screening tool for depression:

• Rapid screening: Can be completed in under 2 minutes
• High sensitivity: Excellent at identifying possible major depression
• Primary care utility: Designed for use in medical settings
• Follow-up indicator: Positive scores warrant complete PHQ-9 assessment
• Population screening: Suitable for large-scale depression screening

Key Features

• Ultra-brief: Only 2 questions for rapid administration
• 4-point scale: 0-3 rating from "not at all" to "nearly every day"
• Core symptoms: Focuses on the most predictive depression symptoms
• Easy scoring: Simple summation with clear cutoff
• High efficiency: Maximizes clinical utility with minimal time investment

Two Core Items

The PHQ-2 assesses the two most essential symptoms of major depression:

• Item 1: Little interest or pleasure in doing things
  • Anhedonia - loss of interest or pleasure
  • Core symptom of major depressive episode
  • Fundamental change in motivation and enjoyment
• Item 2: Feeling down, depressed, or hopeless
  • Depressed mood - persistent sadness or emptiness
  • Essential criterion for major depression diagnosis
  • Subjective experience of emotional distress

Scoring and Interpretation

Score Range: 0-6

• 0-2: Minimal depression - screening negative
• 3-6: Positive screen - further assessment recommended

Clinical Cutoff:

• Score ≥ 3: Positive screen for major depression
• Sensitivity: 83% for major depression
• Specificity: 92% for major depression

Psychometric Properties

• Internal consistency: Cronbach's α = 0.76
• Test-retest reliability: Good short-term stability
• Criterion validity: Strong agreement with PHQ-9
• Construct validity: Correlates well with depression measures
• Sensitivity: 83% for major depression
• Specificity: 92% for major depression
• Positive predictive value: 38% in primary care
• Negative predictive value: 99% in primary care

Clinical Applications

• Primary care screening: Rapid depression detection
• Emergency departments: Quick mental health screening
• Population health: Large-scale depression surveillance
• Telehealth: Brief remote depression assessment
• Research studies: Efficient depression screening in large samples
• Annual wellness visits: Routine depression screening

Follow-up Assessment Protocol

When PHQ-2 screening is positive (≥3), recommended follow-up includes:

• Complete PHQ-9: Comprehensive depression severity assessment
• Clinical interview: Detailed diagnostic evaluation
• Suicide risk assessment: Safety evaluation with PHQ-9 item 9
• Functional assessment: Impact on daily activities and relationships
• Comorbidity screening: Anxiety and other mental health conditions
• Medical evaluation: Rule out medical causes of depression

Screening Recommendations

U.S. Preventive Services Task Force (USPSTF):

• Recommends screening adults for depression in primary care
• PHQ-2 followed by PHQ-9 is an acceptable approach
• Annual screening for high-risk populations
• Adequate systems for follow-up and treatment must be in place

American College of Physicians (ACP):

• Supports depression screening in primary care settings
• Recommends systematic approach with validated tools
• Emphasizes importance of follow-up care coordination

Advantages and Limitations

Advantages:

• Extremely brief and time-efficient
• High sensitivity for depression detection
• Easy to administer and score
• Suitable for any healthcare setting
• Minimal patient burden
• Strong evidence base
• Cost-effective screening approach

Limitations:

• Limited diagnostic specificity (screening tool only)
• Cannot assess depression severity beyond screening threshold
• Requires follow-up assessment for positive screens
• May miss some depression presentations
• Not suitable as sole diagnostic tool
• Lower positive predictive value in low-prevalence settings

Implementation Guidelines

• Universal screening: Can be used for all patients in appropriate settings
• Repeated administration: Suitable for regular monitoring
• Staff training: Minimal training required for administration
• Documentation: Record scores and follow-up plans
• Quality assurance: Ensure positive screens receive appropriate follow-up
• Integration: Incorporate into electronic health records

Special Considerations

• Age considerations: Validated primarily in adult populations
• Cultural factors: Consider cultural expressions of depression
• Medical comorbidity: Depression may be related to medical conditions
• Substance use: Consider substance-induced mood changes
• Grief reactions: Normal grief may elevate scores
• Seasonal patterns: Consider seasonal affective disorder

Quality Improvement

Effective PHQ-2 implementation requires:

• Systematic screening protocols: Clear guidelines for administration
• Care coordination: Pathways for positive screen follow-up
• Provider training: Education on interpretation and next steps
• Patient education: Information about depression and treatment
• Outcome tracking: Monitor screening rates and follow-up care