{
  "abstract": "Background The 11th revision of the International Classification of Diseases (ICD-11) introduced revised diagnostic criteria for a depressive episode (DE) and generalised anxiety disorder (GAD). The International Depression Questionnaire (IDQ) and the International Anxiety Questionnaire (IAQ) are the first self-report measures developed to assess and screen these disorders according to the ICD-11 diagnostic rules.Objective This study aims to validate the IDQ and the IAQ in clinical and community samples, examining internal consistency, factorial validity and construct validity.Methods The cross-sectional, observational multicentre validation study applied internal consistency testing, confirmatory factor analyses and item response theory (IRT) in a clinical sample (n=569; age 18–73; 417 females, 118 males, 34 diverse) and a sample representative of the German general population (n=1001) by age, education and gender (500 females, 499 males, 2 diverse). Factorial and IRT model fit of the IDQ and IAQ as well as concordance with the Patient Health Questionnaire-9 (PHQ-9) and the Generalised Anxiety Disorder-7 (GAD-7) was tested.Results Both questionnaires showed excellent internal consistency (ω=0.96 each) and strong factor loadings. A three-factor IDQ model and a one-factor IAQ model provided the best fit. In the clinical sample, 39.7% met ICD-11 DE criteria and 51.0% GAD criteria (overlap 32.2%). In the general population, prevalence was 5.9% for DE and 9.3% for GAD. Concordance with PHQ-9 and GAD-7 was partial, suggesting differences between ICD-11-based and established screening tools.Conclusions The IDQ and IAQ are psychometrically robust self-report measures for ICD-11 DE and GAD. They are reliable, valid, brief, easy to administer, cost-free and suitable for use in primary care and research across diverse clinical and research settings. Their availability supports standardised screening of depression and GAD in both clinical and community settings.",
  "authors": [
    {
      "affiliations": [
        "Institute for Clinical Psychology and Psychotherapy, Department of Psychology, Medical School Hamburg, Hamburg, Germany"
      ],
      "name": "Johanna Schröder"
    },
    {
      "affiliations": [
        "Department of Psychotraumatology, Clinic St Irmingard, Prien am Chiemsee, Bavaria, Germany"
      ],
      "name": "Leonhard Kratzer"
    },
    {
      "affiliations": [
        "School of Health & Social Care, Edinburgh Napier University, Edinburgh, UK"
      ],
      "name": "Thanos Karatzias"
    },
    {
      "affiliations": [
        "Department of Psychology, Division of Clinical Psychology and Psychological Treatment, Ludwig-Maximilians-Universität München, Munich, Germany"
      ],
      "name": "Anamaria Semm"
    },
    {
      "affiliations": [
        "Clinic for Psychiatry and Psychotherapy I (Weissenau), Ulm, Germany",
        "Centre for Psychiatry Südwürttemberg, Ravensburg, Germany"
      ],
      "name": "Stefan Tschöke"
    },
    {
      "affiliations": [
        "Social and Emotional Neuroscience Group, Department of Psychiatry and Psychotherapy, University Medical Center Hamburg-Eppendorf, Hamburg, HH, Germany"
      ],
      "name": "Sarah Biedermann"
    },
    {
      "affiliations": [
        "Department of Psychotherapy and Psychosomatic Medicine, TUD Dresden University of Technology, Dresden, Germany"
      ],
      "name": "Eva Schäflein"
    },
    {
      "affiliations": [
        "Department of Clinical and Biological Psychology, Catholic University of Eichstätt-Ingolstadt, Ingolstadt, Bavaria, Germany"
      ],
      "name": "Julia König"
    },
    {
      "affiliations": [
        "Landesklinikum Baden, Baden bei Wien, Austria"
      ],
      "name": "Matthias Knefel"
    },
    {
      "affiliations": [
        "Department of Psychology, Maynooth University, Maynooth, Ireland"
      ],
      "name": "Philip Hyland"
    },
    {
      "affiliations": [
        "School of Psychology, University of Ulster, Coleraine, Londonderry, UK"
      ],
      "name": "Mark Shevlin"
    }
  ],
  "title": "International Depression Questionnaire and International Anxiety Questionnaire: validation of brief ICD-11 measures for depression and generalised anxiety disorder",
  "uid": "b903f644-286e-5cfa-8b04-a42c37650551"
}