Hyperarousal and Sleep Quality Following Trauma-Focused Treatment: A Causal Inference Analysis

Comorbid sleep difficulties and posttraumatic stress disorder are common amongst military service members and veterans. Additionally, poor sleep quality following trauma-focused treatment has been linked to posttreatment hyperarousal, a core symptom of posttraumatic stress disorder. However, causal relationships between the two remain unknown. We conducted a hypothetical randomised control trial based on the Rubin Causal Model following Bind and Rubin's four-step method. Participants included 610 veterans and servicemembers that participated in an intensive outpatient programme for posttraumatic stress disorder and related conditions, who were matched into two hypothetical treatment groups where both groups were clinically and demographically similar except for their posttreatment hyperarousal levels. We used Student's test statistics (t) and estimated regression coefficients ( $\hat{\beta }$ ) as test statistics to assess whether posttreatment hyperarousal was related to poor posttreatment sleep quality. The final matched sample included 294 total participants. Results showed that following trauma-focused treatment, veterans with high hyperarousal had poorer global sleep quality ( $\hat{\beta }$  = 1.97, Fisher p < 0.001), a shorter sleep duration ( $\hat{\beta }$  = 0.36, Fisher p≈0.001), increased sleep disturbance ( $\hat{\beta }$  = 0.28, Fisher p < 0.001) and increased daytime dysfunction ( $\hat{\beta }$  = 0.10, Fisher p≈0.047) in comparison to veterans with low posttreatment hyperarousal. These findings further suggested a relationship between post-trauma-focused treatment hyperarousal and poor sleep quality. Further research is needed to investigate post-trauma-focused treatment psychological health in relation to sleep quality.