Insomnia is the most commonly reported symptom and predicts other symptoms of post-traumatic stress disorder in U.S. service members returning from military deployments.

This study retrospectively reviewed records from current members of the U.S. military who had completed the PTSD Checklist (PCL) at 0 and 3-months after returning from deployments. Insomnia was the most commonly reported symptom of PTSD on the PCL and had the highest average severity scores. At initial screen, 41% of those who had been to Iraq or Afghanistan reported sleep problems. Those who had initially reported any insomnia had significantly higher overall scores for PTSD severity at follow-up than did service members without such a complaint. These results show that insomnia is a particularly frequent, severe, and persistent complaint in service members returning from deployment. Such complaints merit particular attention in relation to the possibility of PTSD.