{
  "abstract": "Introduction Patients with chronic somatic diseases such as obesity often develop comorbid depressive symptoms. E-mental health interventions are an innovative and effective treatment option within a stepped care approach. Studies have shown that acceptance and adherence are higher when they are tailored to the specific needs of the target group. This study protocol describes a randomised controlled trial (RCT) of an internet-based self-help intervention, Fit4Mood, to improve mental health in the high-risk group of adults with obesity. The objective of the @ktivPLUS research project is to evaluate the effectiveness, acceptability and cost-effectiveness of the intervention in comparison to an online bibliotherapy.Methods and analysis Eligible individuals will be randomly allocated to an intervention group (access to an internet-based intervention) or to an active control group (access to an online bibliotherapy). Assessments will be conducted before the start of the intervention (baseline (BL)) and 4 months after BL (follow-up (FU)). The primary outcome is the reduction in depressive symptoms (Beck Depression Inventory-II) in n=190 participants. Secondary outcomes are anxiety, quality of life, activity, self-efficacy, resilience, mental and digital health literacy, stress, sleep quality, weight loss, weight management activities and readiness to lose weight, weight self-stigma, uptake, adherence and satisfaction with the intervention, workability and cost-effectiveness at follow-up. Additionally, sociodemographics, health, comorbidities and disabilities, as well as internet-specific information, will be assessed at BL. Intention-to-treat analysis using generalised linear mixed models will be applied.Ethics and dissemination Approval for this study has been granted by the ethics committee of the University of Leipzig (ID: 140/25-ek). All participants will provide informed consent prior to participation in the study. Results will be disseminated in peer-reviewed journals and presented at national and international conferences. In the case of a successful evaluation, the internet-based self-help intervention Fit4Mood will be provided as freeware, which will be easily accessible and free of charge.Trial registration number The current RCT study has been registered at the German Clinical Trials Register (Identifier: DRKS00036178, Registered 24 June 2025; https://www.drks.de/search/de/trial/DRKS00036178).",
  "authors": [
    {
      "affiliations": [
        "Institute for Social Medicine, Occupational Health and Public Health (ISAP), University of Leipzig Faculty of Medicine, Leipzig, Germany"
      ],
      "name": "Katja Schladitz"
    },
    {
      "affiliations": [
        "Institute for Social Medicine, Occupational Health and Public Health (ISAP), University of Leipzig Faculty of Medicine, Leipzig, Germany"
      ],
      "name": "Antonia Buß"
    },
    {
      "affiliations": [
        "Institute for Social Medicine, Occupational Health and Public Health (ISAP), University of Leipzig Faculty of Medicine, Leipzig, Germany"
      ],
      "name": "Alexander Pabst"
    },
    {
      "affiliations": [
        "Institute for Social Medicine, Occupational Health and Public Health (ISAP), University of Leipzig Faculty of Medicine, Leipzig, Germany"
      ],
      "name": "Franziska Dinah Welzel"
    },
    {
      "affiliations": [
        "Helmholtz Institute for Metabolic, Obesity and Vascular Research (HI-MAG), Helmholtz Zentrum München at the University of Leipzig and University Hospital Leipzig, Leipzig, Germany",
        "Medical Department III—Endocrinology, Nephrology, Rheumatology, University of Leipzig Medical Center, Leipzig, Germany"
      ],
      "name": "Matthias Blüher"
    },
    {
      "affiliations": [
        "Helmholtz Institute for Metabolic, Obesity and Vascular Research (HI-MAG), Helmholtz Zentrum München at the University of Leipzig and University Hospital Leipzig, Leipzig, Germany",
        "Medical Department III—Endocrinology, Nephrology, Rheumatology, University of Leipzig Medical Center, Leipzig, Germany"
      ],
      "name": "Michael Stumvoll"
    },
    {
      "affiliations": [
        "Department of Health Economics and Health Services Research, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany"
      ],
      "name": "Christian Brettschneider"
    },
    {
      "affiliations": [
        "Department of Health Economics and Health Services Research, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany"
      ],
      "name": "Hans-Helmut König"
    },
    {
      "affiliations": [
        "Institute for Social Medicine, Occupational Health and Public Health (ISAP), University of Leipzig Faculty of Medicine, Leipzig, Germany"
      ],
      "name": "Steffi G Riedel-Heller"
    },
    {
      "affiliations": [
        "Institute for Social Medicine, Occupational Health and Public Health (ISAP), University of Leipzig Faculty of Medicine, Leipzig, Germany"
      ],
      "name": "Margrit Löbner"
    }
  ],
  "title": "Effectiveness of an internet-based self-help intervention for improving mental health in individuals with obesity: study protocol for a randomised controlled trial",
  "uid": "1a2c5d61-5e4f-5d50-b311-1b1e51aade36"
}