{
  "abstract": "Introduction About 30% of depressed patients suffer from a protracted course in which the disorder continues to cause significant burden despite treatment efforts. While originally developed for relapse prevention, mindfulness-based cognitive therapy (MBCT) has increasingly been investigated in depressed patients with such ‘difficult-to-treat’ courses. This is a protocol for an individual participant data (IPD) meta-analysis aiming to determine efficacy and potential moderators of MBCT treatment effects in this group based on evidence from randomised controlled trials.Methods and analysis Systematic searches in PubMed, Web of Science, Scopus, PsycINFO, EMBASE and the Cochrane Controlled Trials Register for randomised controlled trials were completed on 17 June 2024. Authors of identified studies have contributed IPD, and data extractions have been completed. An update search will be conducted immediately before the start of data analyses. We will investigate the following outcomes: (a) self-reported and observer-reported severity of depression symptomatology, (b) remission and (c) clinically meaningful improvement and deterioration. One-stage and two-stage IPD-MA will be conducted with one-stage models using the observed IPD from all studies simultaneously as the primary approach. One-stage IPD models will include stratified study intercepts and error terms as well as random effects to capture between-study heterogeneity. Moderator analyses will test treatment-covariate interactions for both individual patient-level and study-level characteristics.Ethics and dissemination The results will inform understanding of the use of MBCT in patients with current ‘difficult-to-treat’ depression and will contribute to arguments in favour of or against implementing MBCT as a treatment for this group. They will be published in a peer-reviewed journal and made available to stakeholders in accessible formats. No local ethical review was necessary following consultation with the Ethics and Governance Board of the University of Surrey. Guidance on patient data storage and management will be adhered to throughout.PROSPERO registration number CRD42022332039.",
  "authors": [
    {
      "affiliations": [
        "University of Surrey, Guildford, UK"
      ],
      "name": "Thorsten Barnhofer"
    },
    {
      "affiliations": [
        "Department of Global Public Health, Karolinska Institutet, Stockholm, Sweden"
      ],
      "name": "Maria Niemi"
    },
    {
      "affiliations": [
        "Department of Psychology and Psychotherapy, Witten/Herdecke University, Witten, Germany"
      ],
      "name": "Johannes Michalak"
    },
    {
      "affiliations": [
        "Department of Psychology and Psychotherapy, Witten/Herdecke University, Witten, Germany"
      ],
      "name": "Maria Velana"
    },
    {
      "affiliations": [
        "Department of Psychiatry, University of Oxford, Oxford, UK"
      ],
      "name": "J Mark G Williams"
    },
    {
      "affiliations": [
        "Università di Bologna, Bologna, Italy"
      ],
      "name": "Alberto Chiesa"
    },
    {
      "affiliations": [
        "University of California at San Francisco, San Francisco, California, USA"
      ],
      "name": "Stuart Eisendrath"
    },
    {
      "affiliations": [
        "University of California at San Francisco, San Francisco, California, USA"
      ],
      "name": "Kevin Delucchi"
    },
    {
      "affiliations": [
        "Graduate Department of Psychological Clinical Science, University of Toronto–Scarborough, Toronto, Ontario, Canada"
      ],
      "name": "Zindel Segal"
    },
    {
      "affiliations": [
        "Radboud University Nijmegen, Nijmegen, The Netherlands"
      ],
      "name": "Mira Cladder-Micus"
    },
    {
      "affiliations": [
        "Psychiatry, Radboudumc Instituut voor Wetenschappelijk Onderwijs en Opleidingen, Nijmegen, The Netherlands"
      ],
      "name": "Anne Speckens"
    },
    {
      "affiliations": [
        "Department of Clinical Psychology, Kermanshah University of Medical Sciences (KUMS), Kermanshah, Iran (the Islamic Republic of)"
      ],
      "name": "Ali Akbar Foroughi"
    },
    {
      "affiliations": [
        "Research Network on Chronicity, Primary Care and Health Promotion, Madrid, Spain",
        "University of the Balearic Islands, Palma, Spain",
        "Health Research Institute of the Balearic Islands, Balearic Islands, Spain",
        "Department of Medicine, University of the Balearic Islands, Palma, Spain"
      ],
      "name": "Mauro García-Toro"
    },
    {
      "affiliations": [
        "Department of Psychiatry, University of Oxford, Oxford, UK",
        "Research & Innovation Unit, Parc Sanitari Sant Joan de Déu, Sant Boi de Llobregat, Spain",
        "Consortium for Biomedical Research in Epidemiology and Public Health, Madrid, Spain"
      ],
      "name": "Jesus Montero-Marin"
    },
    {
      "affiliations": [
        "University of Exeter, Exeter, UK"
      ],
      "name": "Barney Dunn"
    },
    {
      "affiliations": [
        "Sussex Partnership NHS Foundation Trust, Worthing, UK",
        "University of Sussex, Brighton, UK"
      ],
      "name": "Clara Strauss"
    },
    {
      "affiliations": [
        "South London and Maudsley NHS Foundation Trust, London, UK"
      ],
      "name": "Florian Alexander Ruths"
    },
    {
      "affiliations": [
        "Royal College of Psychiatrists, London, UK"
      ],
      "name": "Mary Ryan"
    },
    {
      "affiliations": [
        "Department of Psychiatry and Psychotherapy, Technical University of Munich, Munich, Germany",
        "Department of Clinical, Neuro and Developmental Psychology, World Health Organization Collaborating Center for Research and Dissemination of Psychological Interventions, Geneva, Switzerland",
        "Vrije Universiteit, Amsterdam, The Netherlands"
      ],
      "name": "Mathias Harrer"
    }
  ],
  "title": "Efficacy and moderators of mindfulness-based cognitive therapy (MBCT) in ‘Difficult to Treat’ depression: protocol for a systematic review and individual participant data meta-analysis of randomised controlled trials",
  "uid": "206f125e-8c9d-5568-8c7e-81f0d00e9bc6"
}