Mechanisms through which sleep influences intrusive memories: protocol for a trauma film paradigm study

Intrusive memories are common following trauma exposure. However, they can develop into a distressing symptom of posttraumatic stress disorder (PTSD). Recent research examining the role of sleep in the development of intrusive memories demonstrates overnight sleep or a daytime nap following analog trauma exposure (ie, a trauma film), compared to a similar period of wake, results in fewer intrusive memories in the following week. This is consistent with research examining participants who have recently experienced trauma, demonstrating sleep disturbances are highly associated with the development of intrusive memories. However, the mechanisms underlying this are not well understood. Identifying those mechanisms is critical to improving interventions to reduce intrusive memories, and thus, the impacts of posttraumatic stress disorder. This study aims to investigate two potential mechanisms underlying the relationship between sleep and intrusive memories; namely, whether sleep-related memory consolidation and/or executive control over spontaneous cognition explains this relationship. These aims will be investigated through an experimental trauma film study in a healthy adult population (n = 114), where we will compare the effects of a 2-h nap versus 2-h controlled waking period on intrusive memories for the trauma film. In the subsequent week, we will examine the relationship between sleep the previous night and intrusive memories the following day. The outcomes of this project will provide important insights regarding the mechanism(s) explaining the relationship between sleep and intrusive memory frequency. Findings will provide further direction for research investigating sleep-related effects on intrusive memories and may have implications for intervention post trauma exposure.