Pre-deployment daytime and nighttime sleep complaints as predictors of post-deployment PTSD and depression in National Guard troops

There is growing evidence that disturbed sleep is a risk factor for the development of a number of psychiatric diagnoses including depression, PTSD and substance use. The goal of this study was to use a subset of participants from a larger prospective longitudinal study to examine whether preexisting daytime and nighttime sleep disturbances predict depression, PTSD and substance use in US National Guard Soldiers deployed to Iraq. Data on daytime and nighttime sleep complaints, baseline symptoms and personality variables were gathered prior to deployment to Iraq. Measures of psychopathology were collected at three time points post-deployment over the course of two years using both questionnaires and interviews. Multiple regressions were used to predict diagnoses and symptoms of depression, PTSD and substance use. Pre-deployment daytime and nighttime sleep complaints contributed significantly to the prediction of PTSD and depression up to two years after deployment, but not substance use. This study suggests that daytime and nighttime sleep complaints are a risk factor for internalizing disorders including PTSD and depression.