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Sources and accuracy

Where our content comes from

  • Explainers draw on the NHS and the US National Institute of Mental Health (NIMH), and links to those sources are shared with the content. See Explainers.
  • PHQ-9: Kroenke, Spitzer & Williams (2001), Journal of General Internal Medicine 16(9).
  • GAD-7: Spitzer et al. (2006), Archives of Internal Medicine 166(10).

About the questionnaires

The PHQ-9 and GAD-7 were developed by Drs Robert L. Spitzer, Janet B.W. Williams, Kurt Kroenke and colleagues, with an educational grant from Pfizer Inc. No permission is required to reproduce, translate, display or distribute them.

How we keep it accurate

Crisis lines are kept in one place and used for both this website and the tools your AI calls, so they can't drift apart. We check every crisis line and link regularly, and changes to safety content are reviewed before they go live.