Impact of impaired sleep on the development of PTSD symptoms in combat veterans: a prospective longitudinal cohort study.

BACKGROUND: A significant proportion of soldiers return from deployment with symptoms of fatigue, sleep difficulties, and posttraumatic complaints. Disrupted sleep has been proposed as a contributing factor for the development of posttraumatic stress disorder (PTSD). This study investigates the impact of impaired sleep and nightmares before deployment on the development of PTSD symptoms.

METHOD: We collected reports on insomnia symptoms and nightmares in 453 Dutch service members prior to military deployment to Afghanistan. PTSD symptoms were assessed at 6 months postdeployment. The predictive value of insomnia symptoms and nightmares on the development of PTSD symptoms was assessed with a logistic regression analyses, in which was controlled for predeployment mood and anxiety symptoms.

RESULTS: Self-reported predeployment nightmares predicted PTSD symptoms at 6 months (odds ratio 2.992, 95% confidence interval (CI) 1.096-8.551, P < .05), while predeployment insomnia complaints did not (odds ratio 0.976, 95% CI 0.862-1.155, P > .05).

CONCLUSION: In conclusion, this prospective longitudinal cohort study indicates that the existence of predeployment nightmares is associated with an increased risk for the development of PTSD symptoms. Nightmares may be related to hampered fear extinction memory consolidation, which has been associated with REM sleep.