PHQ-9, GAD-7 & More: What Clinical Questionnaires Measure

What clinical questionnaires deliver

When you track your mood, you often use a simple scale: "How am I today, on a 1 to 10?" That's a good start. But what if you want to know more precisely where you stand?

Clinical questionnaires are standardised screening instruments used in psychological and psychiatric practice worldwide. Researchers developed and validated them in large-scale studies. The PHQ-9 was validated in 2001 by Kroenke, Spitzer and Williams against the structured clinical interview as the gold standard (sensitivity 88 percent, specificity 88 percent at a cutoff of 10). The original study is still one of the most cited works in primary-care psychiatry.

The decisive difference from a simple mood score: clinical tests ask specifically about specific symptoms and their frequency over a defined period. That gives a more nuanced picture than a single number.

PHQ-9: The gold standard for depression screening

The Patient Health Questionnaire-9 (PHQ-9) is the world's most widely used questionnaire for detecting depressive symptoms. It consists of 9 questions aligned with the DSM-5 diagnostic criteria.

Each question refers to the last two weeks and is rated on a 0 to 3 scale:

• 0: Not at all
• 1: Several days
• 2: More than half the days
• 3: Nearly every day

The total score ranges from 0 to 27 and divides into five severity levels:

Important: The PHQ-9 is a screening instrument, not a diagnosis. A high score doesn't automatically mean you have depression. But it's a strong signal to consider professional help.

GAD-7: Identifying anxiety disorders

The Generalized Anxiety Disorder-7 (GAD-7) is the PHQ-9's counterpart for anxiety symptoms. With 7 questions it captures the frequency of typical anxiety symptoms over the last two weeks. The validation study by Spitzer et al. (2006) showed sensitivity of 89 percent and specificity of 82 percent for generalised anxiety disorders at a cutoff of 10.

Scoring follows the same pattern (0 to 3 per question), with a total score from 0 to 21:

• 0 to 4: Minimal anxiety
• 5 to 9: Mild anxiety
• 10 to 14: Moderate anxiety
• 15 to 21: Severe anxiety

GAD-7 and PHQ-9 are often used together in practice, since depression and anxiety frequently co-occur.

The compact siblings: PHQ-4, K10 and WHO-5

Beyond PHQ-9 and GAD-7, InnerPulse includes other validated instruments:

• PHQ-4: A short form combining the two most important questions from PHQ-9 and GAD-7. Ideal as a quick weekly screening.
• PHQ-2: An even shorter variant with just 2 items. If both answers are unremarkable, you rarely need the full PHQ-9.
• K10 (Kessler Psychological Distress Scale): Measures general psychological distress with 10 questions. Especially common in Australia and New Zealand.
• WHO-5 (Well-Being Index): A positively worded WHO questionnaire. It measures your general well-being — quality of life rather than symptoms. A systematic review by Topp et al. (2015) confirms its validity as an outcome measure and depression screening instrument across over 200 studies.

How often should you take tests?

A common question. The answer depends on the goal.

For stable self-monitoring, the PHQ-9 or GAD-7 every two to four weeks is usually enough. You catch trends without burning yourself out.

In acute phases or at treatment start, a weekly rhythm makes sense. You see faster whether a measure is working.

If you only want a quick orientation, use the PHQ-4 weekly and add the full PHQ-9 once a month. That combination gives you depth and frequency without overload.

InnerPulse reminds you of your tests and shows your trajectory. You don't have to remember a calendar.

Tests in the therapy context

Therapists work with questionnaires for two reasons. First, to document a baseline. Second, to measure change.

If you're in therapy, your own data is a strong basis for conversation. Instead of remembering how you felt two weeks ago, you show the trajectory. That saves session time and makes observations objective.

InnerPulse offers CSV export. You share your values directly with your therapist or print them.

Limits of clinical questionnaires

Questionnaires are a tool, not an oracle. Three limits worth knowing:

1. Self-assessment fluctuates. Some days you underestimate your symptoms, on others you overestimate them. A single score says little. Trends are more meaningful than single values.
2. Context is missing. A PHQ-9 score of 14 means something different in grief than in a chronic episode. Your therapist interprets. The questionnaire only delivers numbers.
3. No differential diagnosis. PHQ-9 detects depressive symptoms but doesn't distinguish between different causes like thyroid disease, sleep disorder or bipolar phase.

With these limits in mind, the value of clinical tests stays large. They don't replace a professional, but they sharpen your view.

Why tracking over time makes the difference

A single questionnaire score is a snapshot. The actual value emerges through repeated measurement over weeks and months:

• You spot trends: is your score improving? Worsening?
• You see connections: how does your PHQ-9 score correlate with your influence factors?
• You have objective data for conversations with your therapist or doctor.
• You can check the effectiveness of measures, whether therapy, medication or lifestyle change.

InnerPulse shows you the trajectory of your questionnaire results as a trend curve. You see at a glance how your values are evolving.

Clinical tests plus mood tracking equals more clarity

The combination of daily mood tracking and regular clinical questionnaires gives you a full picture:

• Daily tracking shows you short-term fluctuations and their triggers.
• Clinical tests give you a grounded assessment over longer periods.
• 82 influence factors in InnerPulse help you understand what really moves your mood.

That's the InnerPulse approach: not just asking "How am I?", but understanding why, with data instead of guesswork.

Who are clinical questionnaires for?

Clinical screening tests are useful for anyone who wants to better understand their mental health:

• If you're wondering whether your mood is "normal": the tests give you a scientific reference frame.
• If you're in therapy: share your results as a basis for conversation. InnerPulse offers CSV export.
• If you take medication: track whether and how it works.
• If you want to optimise yourself: understand which factors most influence your well-being.

Your data belongs to you

A point that's decisive with sensitive health data: all data in InnerPulse stays on your device. No cloud, no account, no tracking. Your questionnaire results are as private as your journal.

Read more

• PHQ-9: Every question explained shows you what each item really measures.
• Is my medication working? How to use mood data connects the PHQ-9 with therapy tracking.
• Keeping a Mood Journal: The Complete Guide shows how to integrate clinical tests into your daily routine.
• Recognising patterns in your mood takes you from raw data to real insight.
• Original PHQ-9 study: Kroenke, Spitzer & Williams (2001)
• GAD-7 validation: Spitzer et al. (2006)
• Sensitivity to change measurement: Löwe et al. (2004)