The Patient Health Questionnaire-9 (PHQ-9) and the Generalized Anxiety Disorder-7 (GAD-7) are the workhorses of measurement-based care in therapy. They're brief, validated, free to use, and genuinely useful for tracking patient progress. But choosing between them — or knowing when to use both — requires understanding what each instrument measures and where its strengths lie.
PHQ-9: Measuring Depression Severity
The PHQ-9 is a 9-item self-report questionnaire that assesses the severity of depressive symptoms over the past two weeks. Each item corresponds directly to one of the nine DSM-5 criteria for major depressive disorder:
- Anhedonia (little interest or pleasure in doing things)
- Depressed mood (feeling down, depressed, or hopeless)
- Sleep disturbance
- Fatigue or low energy
- Appetite changes
- Negative self-evaluation (feeling like a failure)
- Concentration difficulties
- Psychomotor changes (moving or speaking noticeably slowly or quickly)
- Suicidal ideation
Each item is scored 0–3, yielding a total score of 0–27.
PHQ-9 Score Interpretation
- 0–4: Minimal or no depression
- 5–9: Mild depression
- 10–14: Moderate depression
- 15–19: Moderately severe depression
- 20–27: Severe depression
A score of 10 or above has been validated as a useful threshold for identifying clinically significant depression, with sensitivity and specificity both around 88%.
When to Use the PHQ-9
- Initial screening: When a patient presents with symptoms that may indicate depression.
- Ongoing monitoring: Administered every 2–4 weeks to track treatment response. A 5-point change is considered clinically meaningful.
- Treatment planning: Scores inform decisions about treatment intensity — a patient scoring 22 may need a different approach than one scoring 8.
- Outcome documentation: Quantitative proof of improvement is increasingly required by insurers and valued by patients.
GAD-7: Measuring Anxiety Severity
The GAD-7 is a 7-item self-report questionnaire that assesses generalized anxiety symptoms over the past two weeks:
- Feeling nervous, anxious, or on edge
- Not being able to stop or control worrying
- Worrying too much about different things
- Trouble relaxing
- Restlessness
- Becoming easily annoyed or irritable
- Feeling afraid as if something awful might happen
Each item is scored 0–3, yielding a total score of 0–21.
GAD-7 Score Interpretation
- 0–4: Minimal anxiety
- 5–9: Mild anxiety
- 10–14: Moderate anxiety
- 15–21: Severe anxiety
A score of 10 or above suggests clinically significant anxiety, with sensitivity of 89% and specificity of 82% for generalized anxiety disorder.
When to Use the GAD-7
- Initial screening for anxiety: When a patient reports worry, nervousness, or anxiety symptoms.
- Cross-diagnosis screening: The GAD-7 has moderate sensitivity for panic disorder, social anxiety, and PTSD in addition to GAD.
- Ongoing monitoring: Like the PHQ-9, administered regularly to track response. A 4-point change is clinically meaningful.
- Medication management collaboration: If you're coordinating with a prescriber, GAD-7 scores provide objective data for medication adjustments.
Using PHQ-9 and GAD-7 Together
Depression and anxiety are highly comorbid. Studies consistently find that 50–60% of patients with major depression also meet criteria for an anxiety disorder, and vice versa. This makes a strong case for administering both instruments routinely.
The Combined Protocol
Many evidence-based practices administer both the PHQ-9 and GAD-7 at every session or every other session. This takes patients about 3–4 minutes total and provides a comprehensive mood and anxiety snapshot.
Using digital assessment delivery, you can automate this entirely. Patients complete both instruments on their phone before the session, and you see the results — including trend graphs — before the patient walks in the door.
Tracking Divergent Trajectories
One of the most clinically useful patterns emerges when you track both scores over time and they diverge. For example:
- PHQ-9 improving, GAD-7 stable: Your treatment is addressing depression effectively, but anxiety may need a targeted intervention — perhaps adding worry exposure or relaxation training.
- GAD-7 improving, PHQ-9 stable: Anxiety is responding, but depressive symptoms may require additional focus on behavioral activation or addressing anhedonia directly.
- Both improving in parallel: Treatment is working broadly — stay the course.
- Both worsening: Time to reassess your treatment approach, explore precipitating factors, and consider whether a referral or medication consult is appropriate.
Beyond PHQ-9 and GAD-7
While these two instruments cover the most common presentations, they're not the only assessments worth considering:
- PCL-5: PTSD Checklist for patients with trauma histories
- AUDIT-C: Alcohol use screening
- Columbia Suicide Severity Rating Scale (C-SSRS): For patients endorsing suicidal ideation on PHQ-9 item 9
- WHO-5: A brief positive wellbeing measure that can complement deficit-focused instruments
A comprehensive assessment platform should support all of these and allow you to configure which instruments are sent to which patients at what intervals.
Practical Implementation Tips
Make It Routine, Not Reactive
The biggest mistake is only administering assessments when you think a patient is doing poorly. Routine administration catches deterioration early and provides a baseline that makes improvement visible. It also normalizes the process for patients — it's not an alarm, it's a check-in.
Share Results with Patients
Showing patients their PHQ-9 or GAD-7 trends over time is one of the most powerful therapeutic tools available. When a patient who feels "nothing is changing" can see their score drop from 18 to 11 over eight weeks, it reinforces the value of treatment and sustains motivation through difficult periods.
Automate Delivery
Manual administration — printing paper forms, scoring them by hand, filing results — creates friction that leads to inconsistency. Digital assessment tools handle delivery, scoring, and trend tracking automatically, making measurement-based care effortless to maintain.
Ready to integrate routine assessments into your practice? Explore Mediyn's assessment features and see how automated delivery transforms outcome tracking.