de Terte, IanPeters, Jonathan Bosco Alexander2025-10-132025-10-132025-10-13https://mro.massey.ac.nz/handle/10179/73684This thesis investigates the relationships between electronic media use, sleep, and fatigue. This thesis opens by introducing a conceptual framework for understanding electronic media use and evaluating terminology of sleep and fatigue concepts. The current research field of electronic media use–sleep health in adults is then mapped through an umbrella scoping review. This review revealed a predominance of correlational studies between subjective addiction symptoms and sleep satisfaction through which causal relationships were impossible to delineate. A theoretical perspective is developed on the causal interrelationships between electronic media use, sleep health difficulty, and fatigue through an investigation into experimental and theoretical studies. A novel intervention is then introduced to encourage self-directed use of electronic media in service of sleep health. The intervention is tested using a multiple-baseline single case experimental design study with sailors in active duty with Te Taua Moana O Aotearoa, The Royal New Zealand Navy. Through analysing changes in behavioural and self-report measures of electronic media use, sleep health, sleepiness, vigilance, and fatigue, no immediate effects of the intervention were observed. While longer-term improvements were observed in subjective fatigue at six-month follow-up, these could not be solely attributed to the intervention. Conceptual, theoretical, and practical complications of researching these topics are discussed throughout this thesis and summarised at the end.© The Authorpsychologysleepelectronic media usefatiguevigilanceinterventionsingle casemultiple baselineself reflectionself regulationmaintenance model520302 Clinical psychology