PHQ-9 vs. GAD-7: What's the Difference?

PHQ-9 and GAD-7 are two of the most widely used mental health screening questionnaires in primary care, and they're often confused for each other because they look similar — both are short, both ask you to rate symptoms over the last two weeks, and both produce a simple numeric score. But they measure different things.

PHQ-9: depression

The PHQ-9 (Patient Health Questionnaire-9) screens for symptoms of depression: things like low mood, loss of interest in activities, changes in sleep or appetite, low energy, and difficulty concentrating. It's nine questions, each scored 0–3, giving a total that maps to a severity range from minimal to severe.

GAD-7: anxiety

The GAD-7 (Generalized Anxiety Disorder-7) screens for anxiety symptoms specifically: excessive worry, restlessness, difficulty relaxing, and related physical symptoms. It's seven questions, same 0–3 scoring style, same two-week window.

Why they're often given together

Depression and anxiety commonly occur together, and symptoms can overlap — low energy or trouble concentrating can show up in both. Using both tools gives a clearer picture than either alone, which is why many primary care visits screen with both rather than picking one.

What a score means, and what it doesn't

Both are screening tools, not diagnostic ones. A high score means the symptoms described are significant enough to be worth discussing with a clinician — it's a signal to have a conversation, not a diagnosis on its own. A mental health professional would still take a fuller history before making any diagnosis or treatment decision.