Intrusive memories of psychological trauma are a core clinical feature of posttraumatic stress disorder (PTSD), and in the early period post-trauma may be a potential target for early intervention. Disrupted sleep in the weeks post-trauma is associated with later PTSD. The impact of sleep and intrusive memories immediately post-trauma, and their relation to later PTSD, is unknown. This study assessed the relationship between sleep duration on the first night following a real-life traumatic event and intrusive memories in the subsequent week, and how these might relate to PTSD symptoms at two months.
Patients (n=87) recruited in the emergency department completed a sleep and intrusive memory diary from the day of their trauma and for the subsequent week, with optional actigraphy. PTSD, anxiety and depression symptoms were assessed at one week and two months.
A U-shaped relationship was observed between sleep duration on the first night and intrusive memories over the subsequent week: sleeping “too little” or “too much” was associated with more intrusive memories. Individuals who met CAPS PTSD criteria at two months had three times more intrusive memories in the first week immediately post-trauma than those who did not (M=28.20 vs. 9.96). Post-hoc analysis showed the absence of intrusive memories in the first week post-trauma was only observed in those who did not meet CAPS criteria for PTSD at two months.
Monitoring intrusive memories and sleep in the first week post-trauma, using a simple diary, may help identify individuals more vulnerable to later psychopathology