PHQ-9 vs GAD-7: Using Both in Primary Care
The PHQ-9 measures depression; the GAD-7 measures anxiety. Both are short, self-reported questionnaires scored 0–3 per item, and primary care teams use them together because depression and anxiety overlap heavily. One screen alone misses the other condition, so running both gives a fuller, trackable picture of a patient's mental health over time.
Depression and anxiety are two of the most common conditions primary care sees, and they frequently travel together. A patient who screens positive for one often has the other. That is the practical reason these two tools are usually paired rather than chosen between.
The PHQ-9 (Patient Health Questionnaire-9) is a nine-item screen for depression. It maps directly to the nine diagnostic criteria for major depressive disorder: low mood, loss of interest, sleep changes, fatigue, appetite changes, feelings of worthlessness, trouble concentrating, psychomotor changes, and thoughts of self-harm.
Each item asks how often the symptom has bothered the patient over the past two weeks, scored 0 (not at all) to 3 (nearly every day). Total scores run 0 to 27. Higher scores indicate more severe depression. The ninth item, which asks about thoughts of being better off dead or of self-harm, is treated as a safety flag — a positive response prompts a direct clinical follow-up regardless of the total score.
The GAD-7 (Generalized Anxiety Disorder-7) is a seven-item screen for anxiety. It asks about feeling nervous or on edge, not being able to stop worrying, worrying too much about different things, trouble relaxing, restlessness, irritability, and a sense that something awful might happen.
Like the PHQ-9, each item is scored 0 to 3 over a two-week window, producing a total from 0 to 21. The GAD-7 was built to detect generalized anxiety disorder, but it also performs reasonably well as a general marker of anxiety, including panic and social anxiety symptoms. It is not a diagnosis on its own; it flags a likely problem that a clinician then evaluates.
The core difference is what they measure. The PHQ-9 targets depressive symptoms; the GAD-7 targets anxious ones. They differ in length (nine items versus seven) and in scoring range (0–27 versus 0–21), so the numbers are not interchangeable — a "10" on one does not mean the same thing as a "10" on the other.
They also differ in what a rising score signals clinically. A climbing PHQ-9 points toward worsening depression and, through item nine, toward acute safety risk. A climbing GAD-7 points toward worsening anxiety and the functional impairment that comes with chronic worry. Reading them side by side tells a care team which symptom cluster is driving a patient's distress — or whether both are.
Because depression and anxiety are so often present together, screening for only one leaves a predictable blind spot. A patient whose main complaint is worry may also meet criteria for depression, and vice versa. Running both the PHQ-9 and GAD-7 at intake catches the overlap that a single instrument would miss.
Using both also helps a team target treatment. Two patients with similar overall distress can have very different profiles — one anxiety-dominant, one depression-dominant — and that difference shapes the plan, from which medication a physician considers to what a care manager focuses on between visits. The pair of scores gives a more specific starting point than either number alone.
There is a practical advantage too. Both tools are brief, free, validated across many settings, and easy to administer on paper or through a portal. The combined burden on a patient is a few minutes. That low cost is part of why the pairing has become a standard in primary care behavioral health.
In measurement-based care, screening is not a one-time gate — it is a repeated measurement used to steer treatment. A patient completes the PHQ-9 and GAD-7 at baseline, and then again at regular intervals so the team can see whether symptoms are actually improving.
The goal clinicians usually track is meaningful change over time: a falling score means the current plan is working, while a flat or rising score is a signal to adjust. Rather than assuming a single prescription or referral solved the problem, the team watches the numbers and changes course when they stall. This is the same logic used to manage chronic conditions like diabetes, where a lab value guides the next decision.
The Collaborative Care Model (CoCM) is an evidence-based approach — with more than 90 randomized controlled trials behind it — that builds a small team around the primary care practice a patient already uses: the patient's own physician, a behavioral health care manager, and a consulting psychiatrist who reviews the caseload.
The PHQ-9 and GAD-7 are the model's measuring sticks. The care manager tracks both scores on a registry, reviews patients whose numbers aren't improving with the psychiatric consultant, and adjusts the plan with the physician. Using both tools together is what makes the "measurement-based" part of collaborative care concrete: the team is treating to a target, not to a hunch. Depression and anxiety get watched in parallel because, in real caseloads, they rarely show up alone.
Yes. The PHQ-9 is a nine-item screen for depressive symptoms, and the GAD-7 is a seven-item screen for anxiety symptoms. They measure different conditions, which is why practices often use them together rather than choosing one.
Yes, and it is common. Depression and anxiety frequently co-occur, so many patients have elevated scores on both the PHQ-9 and the GAD-7. Seeing both scores helps a care team understand which symptoms are most prominent and how to prioritize treatment.
No. Both are screening and monitoring instruments, not diagnoses. A high score signals that a clinician should evaluate further; only a qualified provider can diagnose depression or anxiety after a full assessment.
In measurement-based care, the tools are usually repeated at regular intervals so the team can track whether symptoms are improving. The exact schedule depends on the patient and the practice — ask your care team how often they plan to re-screen.
Both are commonly offered through primary care practices, on paper or through a patient portal. If you're concerned about depression or anxiety, ask your primary care practice whether they screen with these tools and how they follow up on the results.
