PHQ-9 and GAD-7: when to administer and how to interpret scores

The PHQ-9 and the GAD-7 are the two most widely used self-report scales in clinical practice, free, validated across languages, and brief enough to administer in five minutes before the session. This guide summarizes how and when to use them, what the scores mean, and what to do when the numbers don't match what you see clinically.

Table of contents

• What they measure
• When to administer and how often
• How to interpret the scores
• When the number doesn't match the clinical picture
• Frequently asked questions

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What they measure

PHQ-9 (Patient Health Questionnaire-9): 9 items mapped to the nine DSM-5 criteria for major depressive episode. Each item is scored 0 to 3 by frequency ("not at all", "several days", "more than half the days", "nearly every day") with a two-week reference window. Total: 0-27.

GAD-7 (Generalized Anxiety Disorder-7): 7 items aligned with DSM-5 criteria for generalized anxiety. Same frequency scale, same two-week window. Total: 0-21.

Both have validated versions across major languages (Kroenke et al. 2001 for PHQ-9; Spitzer et al. 2006 for GAD-7).

Highlight: The PHQ-9 and GAD-7 are screening and monitoring tools, not diagnostic instruments. An elevated score warrants a deeper clinical interview; it does not by itself authorize a diagnosis.

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When to administer and how often

Intake session (first). Administer both scales as baseline. Having a starting number makes it possible to measure real change, not just clinical impression.

Every 2–4 weeks during treatment. Frequent enough to detect meaningful change; spaced enough not to turn the session into a questionnaire routine.

After a critical event. If the patient reports a relevant life event (loss, separation, medical issue, traumatic event), administer both scales in the next session.

Before discharge. Document the score change from baseline as objective evidence of clinical progress.

Don't administer routinely every session. They lose value as a measurement instrument and the patient begins to answer on autopilot.

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How to interpret the scores

PHQ-9

Score	Interpretation	Suggested action
0–4	Minimal	Monitor, no targeted intervention
5–9	Mild	Psychoeducation, close monitoring
10–14	Moderate	Initiate/intensify psychotherapy
15–19	Moderately severe	Consider psychiatric evaluation
20–27	Severe	Urgent psychiatric evaluation, consider intensive care

Item 9 (suicidal ideation) is evaluated separately. Any response other than 0 warrants direct safety exploration in the session.

GAD-7

Score	Interpretation	Suggested action
0–4	Minimal	Monitor
5–9	Mild	Psychoeducation, coping skills
10–14	Moderate	Targeted intervention (CBT, ACT, MI)
15–21	Severe	Consider psychiatric coordination

Clinically significant change

A change of 5 points or more on the PHQ-9 or 4 points or more on the GAD-7 between two administrations is considered clinically significant in the literature. The copilot automatically highlights changes of this magnitude in the session note.

Adapted from the CauceOS skills bank, framework: validated self-report scales (Kroenke 2001; Spitzer 2006).

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When the number doesn't match the clinical picture

The score is information, not verdict. Four scenarios where your judgment prevails:

The number is high; the patient looks stable. Common when the patient has been chronically symptomatic and has developed functional adaptations. The number reflects internal subjective severity; external presentation is another data point. Document both.

The number is low; the patient looks decompensated. Possible explanations: desire to please, defensive minimization, low insight, or the acute episode is concentrated in symptoms not captured by the scale. Explore it in the session.

Sudden drop without obvious reason. Investigate whether the patient understood the items, is rushing, or whether an external change (medication, event, parallel therapy) explains the improvement.

Sudden rise when the session is going well. Sometimes the person allows themselves to register symptoms they previously minimized precisely because they feel clinical safety. It's not a treatment setback. It's new honesty.

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Frequently asked questions

Can I administer PHQ-9 and GAD-7 to adolescents? The PHQ-9 has an adolescent version (PHQ-A) with adjusted cutoffs. For children under 12, specific scales exist (CDI, RCADS). The GAD-7 has been used in adolescents with the same structure, though with less robust validation than in adults.

Can the patient complete the scales at home? Yes, and in fact it's the most common practice. Send the questionnaire via the platform portal one or two days before the session so you have the result when you start.

What if the patient flags suicide risk on PHQ-9 item 9? Activate the safety exploration protocol immediately. Any answer other than 0, even "several days," calls for a direct clinical conversation in the session. See the guide on crisis detection and referral protocol.

Does the system alert me automatically when a score is critical? Yes. If PHQ-9 total exceeds 15, item 9 is non-zero, or GAD-7 exceeds 15, you receive an alert before the session starts and the flag is highlighted in the note.

Do these scales replace others like BDI-II or HAM-D? No. They replace the reflex of "the patient says they're fine" with a number comparable across sessions. For research, forensic evaluation, or complex clinical cases, consider longer scales administered by a trained rater.

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Related articles

• Crisis detection and referral protocol
• How to write a SOAP note in under 5 minutes
• How therapeutic modalities work

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The recommendations in this guide are educational material. The professional judgment of a licensed clinician prevails over any AI-generated suggestion. The scales referenced are screening and monitoring tools, not diagnostic instruments.

Still have questions? Email us at [email protected].