Insomnia symptoms predict the development of post-traumatic stress symptoms following an experimental trauma

Insomnia symptoms prior to traumatic event exposure predict the development of post-traumatic stress symptoms. However, potential mechanisms underlying the association between insomnia and risk for post-traumatic stress disorder symptoms have not been prospectively tested. The current study used the trauma film paradigm to test whether insomnia symptoms prior to analogue trauma exposure predict subsequent analogue post-traumatic stress disorder symptoms, and potential mediators of this relationship, among an at-risk sample of 108 participants. Results indicated that, after covarying for negative affectivity, insomnia symptoms in the 2 weeks prior to analogue trauma exposure significantly predicted increased post-traumatic stress disorder symptoms 3 days and 1 week post-exposure. Moreover, distress immediately after exposure and post-traumatic avoidance mediated the association between insomnia symptoms and post-traumatic stress disorder symptoms 1 week after exposure. Effect sizes were small. The current study uses an analogue trauma and analogue post-traumatic stress disorder symptoms to model clinical symptoms, includes an additional intervention prior to analogue trauma, and lacks a control film. Findings suggest increased reactivity to trauma exposure and subsequent reminders, and attempts to suppress trauma memories may be mechanisms in the association between insomnia symptoms and risk for post-traumatic stress disorder symptoms.