PHQ-9 vs GAD-7: Clinical Decision Tree

Evidence-based guidance for choosing between depression and anxiety screening tools in primary care and mental health settings. When to use each, and when to use both.

12 min read
Updated February 2026

Quick Decision Tree

  • What is the primary presenting concern?

  • Depressed mood, anhedonia, hopelessness

    Use: PHQ-9

    Core depressive symptoms indicate depression-focused screening

  • Worry, nervousness, tension, panic

    Use: GAD-7

    Core anxiety symptoms indicate anxiety-focused screening

  • Both depression and anxiety symptoms

    Use: Both

    Comorbidity common - administer both for detailed assessment

  • Unclear or nonspecific distress

    Use: Both

    Undifferentiated symptoms require dual screening for accurate diagnosis

  • Does the patient have a known diagnosis?

  • Diagnosed Major Depressive Disorder

    Use: PHQ-9

    Use PHQ-9 for treatment monitoring and outcome tracking

  • Diagnosed Generalized Anxiety Disorder

    Use: GAD-7

    Use GAD-7 for symptom severity and treatment response

  • Both depression and anxiety diagnoses

    Use: Both

    Track both conditions separately to assess individual treatment response

  • No full clinical evaluation yet

    Use: Both

    Screening phase - cast wide net to identify primary condition

PHQ-9 vs GAD-7: Detailed Comparison

  • PHQ-9

    Patient Health Questionnaire-9

    Items:9
    Time:2-3 minutes
    Score Range:0-27
    Cutoff:≥10 (moderate depression)
    Sensitivity:88%
    Specificity:88%

    Strengths

    • Directly maps to DSM-5-TR MDD criteria
    • Item 9 screens for suicidality
    • Widely validated in primary care
    • Free to use (Pfizer: no permission needed)
    • Sensitive to treatment change

    Limitations

    • May miss anxiety disorders
    • Less specific in medically ill patients
    • Somatic symptoms can inflate scores

    Best For

    • Depression screening in primary care
    • Treatment monitoring for antidepressants
    • Suicide risk assessment (item 9)
    • Outcome measurement in therapy
    View the PHQ-9 assessment

  • GAD-7

    Generalized Anxiety Disorder-7

    Items:7
    Time:2-3 minutes
    Score Range:0-21
    Cutoff:≥10 (moderate anxiety)
    Sensitivity:89%
    Specificity:82%

    Strengths

    • Screens for multiple anxiety disorders
    • Good performance for GAD, panic, social anxiety
    • Brief and well-tolerated
    • Strong psychometric properties
    • Sensitive to treatment change

    Limitations

    • Less specific for individual anxiety disorders
    • May miss depression if used alone
    • Somatic anxiety can inflate scores

    Best For

    • Anxiety disorder screening
    • Treatment monitoring for anxiolytics
    • Panic disorder detection
    • Social anxiety identification
    View the GAD-7 assessment

Clinical Scenarios: When to Use Each

  • Primary Care Annual Wellness Visit

    Use: Both PHQ-9 and GAD-7

    Universal screening for both depression and anxiety is recommended in primary care. Administering both takes <5 minutes and identifies comorbid conditions. 60% of patients with depression also have anxiety.

    Frequency:Annually, or when symptoms change

  • Patient Presents with Depressed Mood

    Use: PHQ-9 first, consider GAD-7

    Start with PHQ-9 to quantify depression severity and screen for suicidality (item 9). If PHQ-9 ≥10, add GAD-7 to rule out comorbid anxiety, which predicts worse depression outcomes and may require integrated treatment.

    Frequency:Every 2-4 weeks during treatment

  • Patient Presents with Anxiety Symptoms

    Use: GAD-7 first, consider PHQ-9

    Start with GAD-7 to assess anxiety severity. If GAD-7 ≥10, add PHQ-9 because depression commonly coexists with anxiety disorders (50% comorbidity) and may be the primary driver of distress.

    Frequency:Every 2-4 weeks during treatment

  • Monitoring Antidepressant Response

    Use: PHQ-9 primary, GAD-7 secondary

    PHQ-9 is the primary outcome for depression treatment. SSRIs/SNRIs also treat anxiety, so monitor GAD-7 to capture full treatment benefit. Target: 50% reduction in PHQ-9 by 8 weeks.

    Frequency:Weeks 2, 4, 8, 12, then quarterly

  • Therapy for Comorbid Depression and Anxiety

    Use: Both PHQ-9 and GAD-7 equally

    Track both conditions separately to understand which symptoms respond to therapy. Some interventions (e.g., behavioral activation) may improve depression faster than anxiety, or vice versa. Adjust treatment based on differential response.

    Frequency:Every session (weekly or biweekly)

  • Emergency Department Psychiatric Evaluation

    Use: PHQ-9 for suicide screening

    PHQ-9 item 9 screens for suicidal ideation. Positive screen (≥1 on item 9) requires detailed suicide risk assessment (C-SSRS). GAD-7 less critical in acute setting unless panic/anxiety is primary presentation.

    Frequency:Every ED visit with psychiatric component

Interpreting Comorbid Presentations

  • High scores on both (PHQ-9 ≥10 AND GAD-7 ≥10)

    Interpretation:Likely comorbid depression and anxiety

    Clinical Action:

    Integrated treatment targeting both conditions. Consider SSRI/SNRI (treats both) + CBT. Higher risk of treatment resistance and worse functional impairment.

  • PHQ-9 much higher than GAD-7 (PHQ-9 ≥15, GAD-7 <10)

    Interpretation:Primary depression with minimal anxiety

    Clinical Action:

    Depression-focused treatment. Antidepressant monotherapy or behavioral activation. Monitor for emergent anxiety with treatment.

  • GAD-7 much higher than PHQ-9 (GAD-7 ≥15, PHQ-9 <10)

    Interpretation:Primary anxiety disorder with minimal depression

    Clinical Action:

    Anxiety-focused treatment. SSRI/SNRI or CBT with exposure therapy. Monitor for depression development if anxiety is chronic.

  • PHQ-9 item 9 positive (suicidal ideation), regardless of GAD-7

    Interpretation:Elevated suicide risk requiring immediate assessment

    Clinical Action:

    Full C-SSRS assessment, safety planning, crisis intervention. Address depression as primary target. Anxiety increases suicide risk.