PHQ-9: What It Is and How It Helps Track Depression Over Time

When a doctor asks you to fill out the PHQ-9, a nine-question screening tool used to assess the severity of depression symptoms. Also known as the Patient Health Questionnaire-9, it’s one of the most widely used tools in primary care and mental health settings to spot depression early and track progress over time. Unlike vague feelings of sadness, the PHQ-9 turns those feelings into measurable data—helping clinicians decide if treatment is needed, what kind, and whether it’s working.

The PHQ-9 doesn’t diagnose depression on its own, but it gives doctors a clear snapshot of how often you’ve felt down, lost interest in things, had trouble sleeping, or felt worthless over the past two weeks. Each question scores from 0 to 3, adding up to a total that tells you if symptoms are mild, moderate, or severe. A score of 10 or higher often signals major depression and usually means it’s time to talk about treatment options like therapy, medication, or both. It’s not a one-time test, either. Many providers use it every few weeks to see if things are improving—or if a different approach is needed. This makes it more than a checklist; it’s a tracking tool that helps you and your doctor stay on the same page.

What makes the PHQ-9 so useful is how simple it is. You don’t need a psychologist to administer it. Nurses, primary care providers, and even telehealth platforms use it because it’s fast, reliable, and backed by decades of research. It’s also been adapted for use in clinics, emergency rooms, and even during routine checkups. And while it’s not perfect—some people underreport symptoms, others overstate them—it’s still the most consistent way to measure depression across different populations. It’s also linked to real outcomes: studies show that patients whose PHQ-9 scores drop by half after treatment are far more likely to feel better long-term.

It’s not just about the score. The PHQ-9 also includes a question about suicidal thoughts, which triggers immediate follow-up if checked. That’s why it’s not just a screening tool—it’s a safety net. Doctors use it to spot risk before it becomes a crisis. And because it’s standardized, it works whether you’re in a rural clinic or a big hospital. You might not think a short questionnaire matters, but it’s often the first step that leads to real help.

Behind every PHQ-9 score is a person trying to make sense of how they’ve been feeling. That’s why the posts below cover everything from how to interpret your own results, to how antidepressants affect PHQ-9 scores over time, to how it compares to other tools like the GAD-7 for anxiety. You’ll also find guides on how to talk to your doctor about your scores, what to do if your numbers don’t change, and how lifestyle changes like sleep and exercise can shift the numbers in a positive direction. This isn’t just about mental health theory—it’s about what actually works when you’re sitting in a waiting room, holding a clipboard, wondering if you’re broken or just tired. The PHQ-9 doesn’t answer that for you. But it gives you the language to start the conversation.