Reasonable access to brief behavioural insomnia treatment among medical and psychiatric outpatients (RABBIT): a multicentre randomised controlled trial protocol.

INTRODUCTION: Insomnia is a significant global health issue associated with substantial economic costs. International guidelines recommend cognitive behavioural therapy for insomnia (CBT-I) as the first-line treatment for chronic insomnia; however, pharmacotherapy remains more common in clinical practice. Maintaining the effectiveness while reducing the time and frequency of CBT-I is essential for its implementation. We conducted a randomised controlled trial (RCT) to evaluate the effectiveness of a brief behavioural treatment for insomnia (BBTI) that focuses on sleep restriction and stimulus control (SC)-both established as effective standalone interventions. This article presents the study protocol to examine whether adding BBTI to treatment as usual improves outcomes in patients with chronic insomnia.

METHODS AND ANALYSIS: We will conduct a multicentre RCT. We will randomly assign patients with chronic insomnia to two groups (BBTI vs sleep hygiene) in a 1:1 ratio. The BBTI consists of three 15 min sessions over 4 weeks delivered by healthcare professionals following a detailed manual. The primary outcome is the Insomnia Severity Index at 8 weeks. Secondary outcomes include sleep latency, wake after sleep onset, total sleep time, sleep efficiency, Generalized Anxiety Disorder-7, Patient Health Questionnaire-9 and EuroQol-5D-5L. We will conduct the assessment at weeks 0 (baseline), 4 (end of intervention), 8 (post-intervention, primary endpoint) and 12 (follow-up). We will assess each sleep variable from the sleep diary at weeks 0 and 8. The analysis will be performed on an intention-to-treat basis.

ETHICS AND DISSEMINATION: This study has been approved by the Ethics Committee for Clinical and Epidemiological Research of Toyama University (approval no. R2023152).

TRIAL REGISTRATION NUMBER: UMIN000052911; pre-results.