If you've been looking into depression screening, you've probably run into two similar-sounding acronyms: the PHQ-9 and the GAD-7. Both are short questionnaires. Both ask about the last two weeks. Both use the same four answer choices. It's easy to assume they're interchangeable — or to wonder which one you're "supposed" to take.
They're not interchangeable, but they are siblings. The PHQ-9 screens for depression; the GAD-7 screens for anxiety. And because depression and anxiety travel together far more often than they travel alone, the most useful answer to "PHQ-9 or GAD-7?" is frequently both. This article explains how the two tools compare, where they overlap, and — since you're on a depression-screening site — when someone checking for depression should also be checking for anxiety.
Two Tools, One Family
The resemblance between the PHQ-9 and GAD-7 is no accident. Both come from the same research team — Drs. Robert Spitzer, Kurt Kroenke, and Janet Williams — and the same larger project: the Patient Health Questionnaire (PHQ), a self-report adaptation of the PRIME-MD system for identifying common mental health conditions in primary care.
The PHQ-9 came first, with its validation study published in 2001 in the Journal of General Internal Medicine. The GAD-7 followed in 2006, published by Spitzer, Kroenke, Williams, and Bernd Löwe in Archives of Internal Medicine, initially validated as a screener for generalized anxiety disorder and later shown to be useful for flagging other anxiety disorders too.
Because they share designers and design philosophy, they share structure:
- Same time frame. Both ask how often you've been bothered by each problem over the last 2 weeks.
- Same response scale. Not at all (0), several days (1), more than half the days (2), nearly every day (3).
- Same scoring logic. Add up the items for a total score, then read the total against published severity bands.
- Same purpose. Screening and severity tracking — not diagnosis.
That shared DNA is exactly why clinics so often hand patients both questionnaires stapled together. They take about two minutes each and give a two-axis snapshot: one number for depressive symptoms, one for anxious ones.
What Each One Actually Measures
The PHQ-9 maps directly onto the nine DSM criteria for a major depressive episode: loss of interest or pleasure, low mood, sleep problems, fatigue, appetite changes, feelings of worthlessness, trouble concentrating, psychomotor changes, and thoughts of self-harm. (The 9 PHQ-9 questions explained walks through each item.) Scores range from 0 to 27, in five bands: minimal (0–4), mild (5–9), moderate (10–14), moderately severe (15–19), and severe (20–27).
The GAD-7 covers seven core anxiety symptoms: feeling nervous or on edge, being unable to stop worrying, worrying too much about different things, trouble relaxing, restlessness, irritability, and a sense that something awful might happen. Scores range from 0 to 21, in four bands: minimal (0–4), mild (5–9), moderate (10–14), and severe (15–21). Our sister site has a line-by-line breakdown of the GAD-7 questions if you want the anxiety-side equivalent of this kind of walkthrough.
| PHQ-9 | GAD-7 | |
|---|---|---|
| Screens for | Depression | Anxiety |
| Items | 9 | 7 |
| Score range | 0–27 | 0–21 |
| Severity bands | 5 (minimal → severe) | 4 (minimal → severe) |
| Common cut-point | ≥10 | ≥10 |
| Time frame | Last 2 weeks | Last 2 weeks |
| Authors | Kroenke, Spitzer & Williams (2001) | Spitzer, Kroenke, Williams & Löwe (2006) |
One structural difference deserves special mention: only the PHQ-9 asks about thoughts of self-harm (Item 9). The GAD-7 contains nothing comparable. If you take the PHQ-9 and answer anything other than "not at all" on that ninth question, that answer matters on its own, regardless of your total score — please reach out to the 988 Suicide & Crisis Lifeline (call or text 988, available 24/7 in the US), or text HOME to 741741 for the Crisis Text Line.
Where the Two Overlap — and Why That's Confusing
Here's what makes the depression-vs-anxiety question genuinely tricky: several symptoms live on both sides of the fence.
- Sleep trouble appears on the PHQ-9 directly, and anxiety is a notorious cause of lying awake with a racing mind.
- Fatigue is a PHQ-9 item, but chronic worry is exhausting too.
- Trouble concentrating shows up on the PHQ-9, while the GAD-7's "not being able to stop worrying" often produces exactly that concentration problem.
- Restlessness is explicitly on both scales — PHQ-9 Item 8 (fidgety, restless) and GAD-7 Item 5.
So a person whose core problem is anxiety can still put real points on a PHQ-9 through sleep, fatigue, concentration, and restlessness items — and a depressed person can score on the GAD-7 through irritability and trouble relaxing. Neither scale is "wrong" when that happens; the symptoms are genuinely shared. But it means a single elevated score can't tell you which condition is driving it. Taking both, and comparing the two numbers, gives a much clearer signal about where the weight of your symptoms sits.
If You're Screening for Depression, Should You Also Check Anxiety?
Often, yes — and this is the practical heart of the comparison.
Depression and anxiety co-occur remarkably often. Research consistently finds that a large share of people who meet criteria for depression also experience clinically significant anxiety, and vice versa; the same research group behind both scales documented in a 2007 Annals of Internal Medicine study how commonly anxiety disorders show up in primary care patients and how much they overlap with depression. We cover the why and the what-to-do in depth in our guide to depression and anxiety comorbidity, but the short version is: the two conditions share risk factors, feed each other (worry disturbs sleep, poor sleep drags mood down, low mood breeds more worry), and frequently need to be addressed together for treatment to stick.
That has concrete implications for anyone using a depression screener:
If your PHQ-9 score is elevated, it's worth spending two more minutes on a GAD-7 anxiety test. If anxiety is riding along with your depression, a clinician will want to know — it can shape the choice of therapy and, when medication is involved, the prescribing conversation.
If your PHQ-9 score is low but you still feel awful, anxiety is one of the most common explanations. Dread, muscle tension, a mind that won't shut off — these can make life miserable while barely registering on a depression scale. A low depression score plus a high anxiety score is a coherent, common pattern, not a contradiction.
If both scores are elevated, that's especially worth bringing to a professional. Co-occurring depression and anxiety tends to mean more severe symptoms and a longer road than either alone — and knowing that early leads to better-matched care.
Which Should You Take First?
Start with the one that matches your loudest symptom. If the dominant note of your last two weeks has been heaviness — lost interest, low mood, hopelessness, everything requiring more effort than it should — start with the PHQ-9 depression test. If the dominant note has been revving — worry you can't put down, tension, edge-of-your-seat unease — start with the GAD-7.
Then, honestly, take the other one anyway. Two minutes each, and together they cover the two most common mental health conditions in the US. Many primary care offices administer them as a pair for exactly this reason, and there's no rule saying self-screeners can't do the same.
Whatever the numbers say, remember what these tools are: screeners, not diagnoses. A high score on either scale is a signal to talk to a doctor or therapist, who can assess your full history and rule out look-alikes. A low score doesn't override your lived experience. And the scores are most useful when you bring them — both of them — into that conversation as a starting point.
The Bottom Line
The PHQ-9 and GAD-7 are companion instruments from the same authors, built the same way, for two different targets: depression and anxiety. They overlap where the conditions overlap — sleep, fatigue, concentration, restlessness — which is exactly why one score alone can be ambiguous, and why screening for both is often the smarter move. Depression and anxiety co-occur too often to check only one box.
Get your depression number with our free PHQ-9 test — nine questions, about two minutes, scored instantly with a full interpretation. Then round out the picture with the free GAD-7 test at gad7test.com. And if you're having thoughts of self-harm at any point, don't wait on any questionnaire: call or text 988 now.