Multiple Baseline Clinical Trial Investigating the Efficacy of an Acceptance and Commitment Therapy (ACT)-Based Sleep Intervention for Adults Presenting with Insomnia (SLEAPI) on Sleep, Mental Health, and Quality of Life

Eligible participants will be randomised into one of three baseline lengths (2, 3 or 4 weeks), delivered non-concurrently. After completion of baseline monitoring, participants will begin the SLEAPI intervention, delivered in-person at the La Trobe University Psychology Clinic. SLEAPI aims to target processes associated with hyperarousal and sleep disturbance: inflexibility, cognitive fusion, and experiential avoidance. Like other ACT approaches for insomnia there is the encouragement for participants to shift their efforts to values-based living, rather than continuing to focus on trying to fix sleep problems through over-control and rigid routines. This is done through encouraging participants to explore experientially whether the ways they cope with insomnia are leading to life becoming smaller, and the sleep problems bigger and more central to their lives. Individualized SLEAPI consists of 8 x 50-minute sessions delivered over 8 weeks. Prior to all sessions, participants will have completed online sleep diaries and questionnaires. The clinicians will have calculated everyone’s questionnaire and sleep diary values for discussion and problem-solving. SLEAPI will be delivered by provisional psychologists under the supervision of a clinical psychologist. Participants in SLEAPI will be given a Workbook that will be adapted from the original group intervention (available from Dr Eric Morris, La Trobe University) and developed for this trial. The workbook includes information presented in session, worksheets, and exercises, to refer in in session and at home. Provisional Psychologists will follow a SLEAPI manual adapted from the original group intervention (available from Dr Eric Morris, La Trobe University) and developed for this trial. Each SLEAPI session has an aim, where the provisional psychologist will describe a concept or strategy, and use exercises or worksheets to demonstrate the concept or strategy for the participant. Participants will be asked to complete homework exercises between sessions to reinforce strategies learnt during the session and record progress. The ACT Fidelity Measure (ACT-FM) (O'Neill et al., 2019) will be utilised at the end of every session to ensure the intervention is being delivered appropriately and consistently among clinicians. Upon completion of the intervention, participants will then begin a follow-up monitoring period, ranging from 2-4 weeks depending on the length of their baseline.