Do sleep problems mediate the relationship between traumatic brain injury and development of mental health symptoms after deployment?

Abstract

Study objectives: Military members screening positive for blast-related traumatic brain injury (TBI) may subsequently screen positive for posttraumatic stress disorder (PTSD) or depression. The role of sleep as a mediating factor in the development of mental health symptoms was explored.

Design: Prospective study with symptoms evaluated at two time points.

Setting: Postdeployment service in Iraq, Afghanistan, or Kuwait during 2008 and 2009.

Participants: There were 29,640 US Navy and Marine Corps men (29,019 who did not screen positive for PTSD at baseline, 27,702 who did not screen positive for depression at baseline, and 27,320 who did not screen positive at baseline for either condition).

Measurements and results: After controlling for sleep problems, the adjusted odds of receiving a positive PTSD screening at follow-up decreased from 1.61 (95% confidence interval [CI] 1.21-2.14) to 1.32 (95% CI 0.99-1.77) for a subject screening positive for TBI relative to a subject screening negative, suggesting that sleep problems mediated 26% of TBI's effect on development of PTSD. Likewise, after controlling for sleep problems, the adjusted odds of receiving a positive depression screening decreased from 1.41 (95% CI 1.11-1.80) to 1.15 (95% CI 0.90-1.47), suggesting that sleep problems mediated 41% of TBI's effect on development of depression. Results were similar for those with either PTSD or depression (37% mediated).

Conclusions: These results suggest that sleep problems mediate the effect of a positive TBI screening on the development of mental health disorders, and sleep problems may be an early indicator of risk for PTSD or depression.

Figure 1

Diagram depicting the role of self-reported sleep problems in mediating the association between a positive TBI screening on the PDHA and a new positive PTSD screening on the PDHRA (n = 29,019 men). Bolding denotes estimates obtained from the final adjusted model (Model 3). CI, confidence interval; OR, odds ratio; PDHA, Post-Deployment Health Assessment; PDHRA, Post-Deployment Health Reassessment; PTSD, posttraumatic stress disorder; TBI, traumatic brain injury. Model is adjusted for pay grade, service branch, service component, age, deployment location, combat experiences, deployment length, and time between assessments.

Figure 2

Diagram depicting the role of self-reported sleep problems in mediating the association between a positive TBI screening on the PDHA and a new positive depression screening on the PDHRA (n = 27,702 men). Bolding denotes estimates obtained from the final adjusted model (Model 3). CI, confidence interval; OR, odds ratio; PDHA, Post-Deployment Health Assessment; PDHRA, Post-Deployment Health Reassessment; TBI, traumatic brain injury. Model is adjusted for pay grade, service branch, service component, age, deployment location, combat experiences, deployment length, and time between assessments.

Figure 3

Diagram depicting the role of self-reported sleep problems in mediating the association between a positive TBI screening on the PDHA and a new positive PTSD or depression screening on the PDHRA (n = 27,320 men). Bolding denotes estimates obtained from the final adjusted model (Model 3). CI, confidence interval; OR, odds ratio; PDHA, Post-Deployment Health Assessment; PDHRA, Post-Deployment Health Reassessment; PTSD, posttraumatic stress disorder; TBI, traumatic brain injury. Model is adjusted for pay grade, service branch, service component, age, deployment location, combat experiences, deployment length, and time between assessments.