Dismantling cognitive-behavioral therapy for chronic insomnia: a protocol for a systematic review and component network meta-analysis

Introduction Insomnia is highly prevalent and disabling. Clinical practice guidelines recommend cognitive-behavioral therapy for insomnia (CBTI) as the first-line treatment. However, CBTI includes various combinations of many different components and its clinical benefits have been shown as a package, whereas the effect of each component remains unclear. In this study, we will explore the effect of each component of CBTI with the use of component network meta-analysis. Methods and analysis We will include all randomized controlled trials that compared any form of CBTI against another form of CBTI or a control condition in the treatment of adults with chronic insomnia. Concomitant treatments will be allowed as long as they are equally distributed among the arms. We will include both primary and secondary insomnia. The primary outcome of interest in this study is (1) treatment efficacy (remission defined as reaching a satisfactory state at endpoint measured by any validated self-reported scale) at four weeks post-treatment or at its closest time point. Secondary outcomes are (2) acceptability, (3) sleep diary measures and (4) efficacy at long-term follow-up. We will systematically search in PubMed, CENTRAL, PsycINFO and WHO International Clinical Trials Registry Platform. We will assess risk of bias using Cochrane Risk of Bias 2.0 tool. We will conduct component network meta-analysis with the netmeta package in R. Ethics and dissemination This study will use published data and does not require ethical approval. Findings will be disseminated in a peer-reviewed journal. PROSPERO CRD42022324233. ### Competing Interest Statement YF has received consultancy fee from Panasonic outside the submitted work. MS reports personal fees from SONY outside the submitted work. SF has a research grant from JSPS KAKENHI Grant Number JP 20K18964 and the KDDI Foundation. SK has a research grant from Mental Health Okamoto Memorial Foundation and Fujiwara Memorial Foundation. TAF reports grants and personal fees from Mitsubishi-Tanabe, personal fees from SONY, grants and personal fees from Shionogi, outside the submitted work; In addition, TAF has a patent 2020-548587 concerning smartphone CBT apps pending, and intellectual properties for Kokoro-app licensed to Mitsubishi-Tanabe. EGO has received research and consultancy fees from Angelini Pharma. EGO is supported by the National Institute for Health Research (NIHR) Research Professorship to Professor Andrea Cipriani (grant RP-2017-08-ST2-006), by the National Institute for Health Research (NIHR) Applied Research Collaboration (ARC) Oxford and Thames Valley, by the National Institute for Health Research (NIHR) Oxford cognitive health Clinical Research Facility and by the NIHR Oxford Health Biomedical Research Centre (grant BRC-1215-20005) OE was supported by the Swiss National Science Foundation (Ambizione grant number 180083) MP reports no competing interest. ### Clinical Protocols ### Funding Statement No financial support was used. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The study will use ONLY publicly available data located by our systematic review. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes Data and code used for analyses will be available from the corresponding author on reasonable request.