Depression Screening

Description

This skill helps administer and interpret validated depression screening instruments. The PHQ-2 serves as a brief initial screener, while the PHQ-9 provides comprehensive assessment of depression severity aligned with DSM criteria.

Clinical Context: These tools help quantify depression symptoms, track treatment response, and support clinical decision-making. They are support tools that supplement, not replace, comprehensive clinical evaluation.

Quick Reference

Assessment Comparison

Assessment	Items	Time	Purpose	Cutoff	When to Use
PHQ-2	2	<1 min	Brief screening	≥3 → Full PHQ-9	Time-limited settings, universal screening
PHQ-9	9	2-3 min	Severity assessment	≥10 = Moderate+	Comprehensive assessment, treatment monitoring

For detailed comparison: See references/screening-comparison.md

PHQ-9 Severity Levels

Score	Severity	First-Line Treatment	Follow-up
0-4	Minimal	Monitor, psychoeducation	Annual or as needed
5-9	Mild	Behavioral interventions	2-4 weeks
10-14	Moderate	Therapy or medication	2-4 weeks
15-19	Moderately Severe	Combination therapy, specialty referral	1-2 weeks
20-27	Severe	Specialty referral, higher level of care	Weekly+

For detailed severity interpretations: See references/severity-levels.md

For treatment recommendations: See references/clinical-decision-trees.md

⚠️ CRITICAL SAFETY WARNING

PHQ-9 Item 9: Suicidal Ideation

Item 9: "Thoughts that you would be better off dead or of hurting yourself in some way"

ANY score > 0 on Item 9 requires IMMEDIATE action:

1. Stop and address immediately - do not wait until end of assessment
2. Assess safety fully (ideation, plan, intent, means, protective factors)
3. Intervene based on risk level (safety plan, crisis resources, emergency evaluation)
4. Document thoroughly

Item 9 Response Protocol

digraph item9_protocol {
    rankdir=TB;
    node [shape=box, style=rounded];

    item9 [label="PHQ-9 Item 9\nscore > 0", shape=ellipse, style="filled", fillcolor=orange];
    stop [label="STOP\nAssessment", style="filled", fillcolor=red, fontcolor=white];
    assess [label="Assess Safety:\n• Active ideation?\n• Plan/intent?\n• Means access?\n• Protective factors?", style="filled", fillcolor=yellow];
    risk_level [label="Risk Level?", shape=diamond];
    low [label="Low Risk:\n• Safety plan\n• Follow-up\n• Resources", style="filled", fillcolor=lightgreen];
    moderate [label="Moderate Risk:\n• Safety plan\n• Crisis contacts\n• Urgent referral\n• Reduce means", style="filled", fillcolor=yellow];
    high [label="High Risk:\n• Do not leave alone\n• Emergency eval\n• 988/911\n• Family notification", style="filled", fillcolor=red, fontcolor=white];
    document [label="Document\nThoroughly", style="filled", fillcolor=lightblue];

    item9 -> stop;
    stop -> assess;
    assess -> risk_level;
    risk_level -> low [label="Low"];
    risk_level -> moderate [label="Moderate"];
    risk_level -> high [label="High/\nImminent"];
    low -> document;
    moderate -> document;
    high -> document;
}

See detailed protocol: references/item-9-safety-protocol.md

Crisis Resources:

• 988 Suicide & Crisis Lifeline (call or text)
• Crisis Text Line: Text HOME to 741741
• Emergency: 911

Universal crisis protocols: ../../docs/references/crisis-protocols.md

Interactive Administration (Optional)

Use this mode when the clinician says "start" or "administer" the PHQ-2/PHQ-9.

1. Confirm readiness and explain the past 2 weeks time frame plus the 0-3 response scale.
2. Ask one item at a time (verbatim from the asset file) and wait for a response before continuing.
3. Accept numeric or verbal responses; if unclear or out of range, ask for clarification.
4. Record each response and keep a running total.
5. Item 9 safety rule: If Item 9 > 0, STOP and follow the Item 9 safety protocol before continuing.
6. After the final item, calculate the total score, interpret severity, and provide next-step guidance.
7. Offer a brief documentation summary if requested.

Assessment Tools

PHQ-9 (Patient Health Questionnaire-9)

Complete assessment with items, scoring, and documentation: → assets/phq-9.md

Key Facts:

• 9 items, 0-3 scale each, total score 0-27
• Cutoff ≥10: 88% sensitivity/specificity for major depression
• Item 9: Screens for suicidal ideation - requires immediate follow-up if positive
• Treatment response: 5-point decrease = response, 10-point = clinically significant
• Validated for screening, diagnosis support, and treatment monitoring

PHQ-2 (Patient Health Questionnaire-2)

Complete assessment with items, scoring, and documentation: → assets/phq-2.md

Key Facts:

• 2 items (first 2 from PHQ-9), 0-3 scale each, total score 0-6
• Cutoff ≥3: Positive screen → administer full PHQ-9
• Use for: Rapid screening, universal screening in time-limited settings
• Does NOT: Assess severity or include suicidal ideation screening

When to use PHQ-2 vs PHQ-9: See references/screening-comparison.md

Clinical Workflow

1. Choose Assessment

digraph assessment_selection {
    rankdir=LR;
    node [shape=box, style=rounded];

    start [label="Patient\nPresentation", shape=ellipse];
    time_check [label="Time-limited\nencounter?", shape=diamond];
    purpose_check [label="Treatment\nmonitoring?", shape=diamond];
    phq2 [label="Start with\nPHQ-2", style="filled", fillcolor=lightblue];
    phq2_score [label="PHQ-2\nscore ≥3?", shape=diamond];
    phq9 [label="Administer\nPHQ-9", style="filled", fillcolor=lightgreen];
    monitor [label="Negative\nscreen", style="filled", fillcolor=gray90];

    start -> time_check;
    time_check -> phq2 [label="yes\n(primary care,\nER)"];
    time_check -> purpose_check [label="no"];
    purpose_check -> phq9 [label="yes"];
    purpose_check -> phq9 [label="no\n(suspected\ndepression)"];
    phq2 -> phq2_score;
    phq2_score -> phq9 [label="yes"];
    phq2_score -> monitor [label="no"];
}

2. Administer Assessment

PHQ-2: assets/phq-2.md - 2 items, <1 minute PHQ-9: assets/phq-9.md - 9 items, 2-3 minutes

3. Score and Interpret

Scoring:

• Sum all item responses
• PHQ-2: 0-6 range
• PHQ-9: 0-27 range

Interpretation:

• See quick reference table above
• Detailed interpretations: references/severity-levels.md

⚠️ Check Item 9 immediately - if positive, see safety protocol

4. Clinical Decision-Making

Treatment Decision Pathway

digraph treatment_decision {
    rankdir=TB;
    node [shape=box, style=rounded];

    score [label="PHQ-9\nTotal Score", shape=ellipse];
    minimal [label="0-4\nMinimal", shape=box];
    mild [label="5-9\nMild", shape=box];
    moderate [label="10-14\nModerate", shape=box];
    mod_severe [label="15-19\nMod. Severe", shape=box];
    severe [label="20-27\nSevere", shape=box];

    tx_minimal [label="• Monitor\n• Psychoeducation\n• Annual f/u", style="filled", fillcolor=gray90];
    tx_mild [label="• Behavioral interventions\n• Lifestyle changes\n• F/u 2-4 weeks", style="filled", fillcolor=lightblue];
    tx_moderate [label="• Therapy OR\n  medication\n• F/u 2-4 weeks", style="filled", fillcolor=yellow];
    tx_mod_severe [label="• Combination therapy\n• Specialty referral\n• F/u 1-2 weeks", style="filled", fillcolor=orange];
    tx_severe [label="• Immediate specialty\n• Higher LOC\n• Weekly+ f/u", style="filled", fillcolor=red, fontcolor=white];

    score -> minimal;
    score -> mild;
    score -> moderate;
    score -> mod_severe;
    score -> severe;

    minimal -> tx_minimal;
    mild -> tx_mild;
    moderate -> tx_moderate;
    mod_severe -> tx_mod_severe;
    severe -> tx_severe;
}

Follow clinical decision trees: references/clinical-decision-trees.md

⚠️ Any Item 9 > 0: Follow safety protocol regardless of total score

5. Document

Use documentation templates in:

• assets/phq-2.md
• assets/phq-9.md

Documentation standards: ../../docs/references/documentation-standards.md

Treatment Monitoring

Use PHQ-9 to track progress:

• Baseline: Administer at treatment start
• Follow-up: Every 2-4 weeks during active treatment
• Response indicators:
  • <5-point decrease: Minimal response (consider treatment change)
  • 5-9 point decrease: Partial response (continue, monitor)
  • ≥10-point decrease: Clinically significant improvement
  • Score <5: Remission (treatment goal)

Do NOT use PHQ-2 for treatment monitoring - insufficient detail

Special Considerations

• Medical comorbidity: Physical illness elevates somatic scores (items 3,4,5,8)—interpret in context, treat depression regardless
• Cultural factors: Symptom expression varies; use culturally validated versions when available
• Age: PHQ-A for adolescents; validated for older adults; different tools for children <12
• Substance use: Can confound scores; assess post-detox for baseline; integrated treatment required

Referral Guidelines

When to Refer to Specialty Mental Health

Immediate/Urgent:

• PHQ-9 ≥15 at initial presentation
• Any suicidal ideation (Item 9 > 0)
• Inadequate response to initial treatment
• Patient request for specialty care

Routine:

• PHQ-9 10-14 if patient prefers specialist
• Complex presentation (trauma, substance use, medical comorbidity)
• Need for specialized therapy

Complete referral guidance: ../../docs/references/referral-guidelines.md

Limitations

Screening tools, not diagnostic instruments. Do not replace clinical assessment. Clinical judgment supersedes scores. Potential issues: false positives (medical illness), false negatives (minimization, literacy), cultural/linguistic factors.

Usage Examples

Example requests: "Administer PHQ-9", "Screen for depression", "Score and interpret PHQ-9", "Treatment for score 16", "Item 9 positive—what now?"

References

Primary Literature:

• Kroenke K, Spitzer RL, Williams JB. The PHQ-9: validity of a brief depression severity measure. J Gen Intern Med. 2001;16(9):606-613.
• Kroenke K, Spitzer RL, Williams JB. The Patient Health Questionnaire-2: validity of a two-item depression screener. Med Care. 2003;41(11):1284-1292.

Clinical Guidelines:

• American Psychological Association. (2019). Clinical Practice Guideline for the Treatment of Depression.
• Veterans Affairs/DoD. (2022). Clinical Practice Guideline for Management of Major Depressive Disorder.

No copyright restrictions - PHQ-2 and PHQ-9 are freely available for clinical and research use