Differences in Sleep and Mood State Prior to Exposure are Associated With Success and Failure in a High Stress Environment: Special Forces Selection

The U.S. Army Special Forces Assessment and Selection course (SFAS) is an extremely stressful, physically and mentally challenging 19-20 days long selection procedure. Only 30%-40% of soldiers who volunteer for it complete it. The purpose of SFAS is to identify soldiers who can complete 1-2 years of physically and mentally challenging training for the Special Forces and be successful Special Forces soldiers thereafter. This study examined association of pre-course self-reported mood state and sleep quality and quantity with subsequent success or failure at SFAS. Data from 780 male soldiers collected in 2015-2017 were analysed. Prior to SFAS, the Profile of Mood States (POMS), Dimension of Anger Reactivity (DAR), Duke University Social Support Questionnaire (Duke-SSQ), General Anxiety Disorder and Depression inventories (GAD-7), and Pittsburgh Sleep Quality Index (PSQI) were administered. Group differences among these variables and their ability to predict selection versus non-selection were assessed. There were significant differences in pre-SFAS mood and sleep in selected versus non-selected volunteers. Selected candidates reported more positive mood (POMS vigour, friendliness), less negative mood (POMS depression, anger, fatigue, confusion), less anger (DAR), and less social support (Duke-SSQ). Selected candidates reported longer and higher quality sleep (PSQI) than non-selected soldiers. These differences were not sufficient to serve as an accurate predictive model based on logistic regression, as the best-fit model accounted for 4.9% of the variance. In conclusion, there were differences in pre-course mood state and sleep between those who succeeded or failed a stressful course that selects individuals for elite military training and service, but they were not of sufficient strength to predict individual success of failure.