PHQ-9 Validated Screening

About Depression Test Online

Free, confidential depression screening based on the PHQ-9 and PHQ-2 — widely used questionnaires developed by leading researchers.

Last reviewed: January 2026

Our Mission

Depression is a common mental health condition, affecting many people worldwide. Yet many go years without understanding what they're experiencing. Our mission is to provide free, accessible depression screening based on widely used questionnaires — helping people take a first step toward understanding their mental health.

PHQ-9 Validated Research

Research Foundation

Our screening tools were developed by leading researchers and studied in many peer-reviewed publications

The PHQ-9 (Patient Health Questionnaire-9) used on this platform is the most widely used depression screening instrument in the world. It was developed by researchers at Columbia University and has been validated in over 500 peer-reviewed studies across diverse populations.

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Dr. Kurt Kroenke

Professor of Medicine

Indiana University School of Medicine

Lead developer of the PHQ-9 and PHQ-2 depression screening instruments. Pioneer in developing brief, validated screening tools for primary care settings.

Key Publication:

Kroenke, K., Spitzer, R. L., & Williams, J. B. (2001). The PHQ-9: validity of a brief depression severity measure. Journal of General Internal Medicine, 16(9), 606-613.

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Dr. Robert L. Spitzer

Professor

Columbia University

Co-developer of the PHQ-9 and contributor to widely used diagnostic standards.

Key Publication:

Spitzer, R. L., Kroenke, K., & Williams, J. B. (1999). Validation and utility of a self-report version of PRIME-MD: the PHQ primary care study. JAMA, 282(18), 1737-1744.

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Dr. Janet B.W. Williams

Professor

Columbia University

Co-developer of the PHQ-9 and PRIME-MD. Contributor to structured interview and assessment instruments.

Key Publication:

Williams, J. B., et al. (2002). The STRUCTURED CLINICAL INTERVIEW FOR DSM-IV (SCID). The American Psychiatric Publishing Textbook of Psychiatry.

Note: These researchers developed the original PHQ-9 screening instrument. Our platform provides a digital implementation of their publicly available screening tool for educational purposes.

PHQ-9: Widely Used Questionnaire

The PHQ-9 is widely used and studied as a depression screening questionnaire:

  • Supported by peer-reviewed research across diverse populations
  • Used in many settings globally
  • Translated into over 80 languages
  • Referenced by major health organizations including WHO

Our Approach

We prioritize research-backed tools, privacy, and accessibility:

Research-Backed Tools

We use the PHQ-9, PHQ-2, PHQ-A (for adolescents), and EPDS (for perinatal depression) — widely used questionnaires with clear scoring.

Learn about our assessments

Complete Privacy

Your responses are processed locally in your browser and are not sent to our servers. Your progress and results may be saved on this device using your browser's local storage. We do not sell personal information. Some third-party services (such as advertising or affiliate links) may use cookies or similar technologies. See our privacy policy for details.

Read our privacy policy

Clear Limitations

We clearly separate screening from diagnosis and explain what scores can and cannot tell you.

Comprehensive Resources

Beyond screening, we provide educational information about common symptoms and support options.

Explore depression resources

Content Standards

We maintain rigorous standards for all content:

  • All assessments based on PHQ instruments validated in peer-reviewed research
  • Information sourced from NIMH, CDC, WHO, and peer-reviewed journals
  • Content regularly updated to reflect current evidence
  • Clear distinction between screening and diagnosis is maintained
View our editorial guidelines

Our Commitment

We are committed to providing accurate, helpful, and judgment-free information about depression. Our goal is to help people understand their symptoms and connect with support that fits their needs.

Ready to Understand Your Symptoms?

Take a free, confidential PHQ-9 depression screening — a widely used questionnaire

Start Free Depression Screening

Important Disclaimer

Our screening tools are for educational purposes only. They cannot diagnose depression — only a qualified professional can do that after an appropriate evaluation. If you're concerned about your symptoms, consider reaching out to a qualified provider.