Biochemical and mood changes dissociate during exposure to intense military training

Abstract

Exposure to intense stress is known to alter affective and cognitive behavior more profoundly in some individuals than others. Recently, we had the opportunity to examine the biochemical, cognitive and mood changes (Profile of Moods) associated with intense military training known as SERE school (Survive, Evade, Resist, Escape). SERE is a unique environment to examine Soldiers’ responses to stress in a realistic, standardized and carefully monitored military context in which students apply newly learned resistance skills to a variety of captivity scenarios. From baseline to the end of SERE (~2wks), serum testosterone and prolactin were both substantially depressed from 468ng/ml to 156ng/ml and 13.8ng/ml to 5.46ng/ml, respectively (p <.001). In contrast, epinephrine and norepinepherine remained elevated from 41pg/ml to 67pg/ml and 468pg/ml to 754.8pg/ml, respectively (p<.001). Interestingly, changes in mood states were not reflective of these prolonged endocrine alterations, as depression, tension, anger, and confusion returned to approximately baseline levels at recovery. This suggests that changes in these hormonal levels are not reliable biomarkers of mood in this elite population. This research was supported by the Office of Naval Research and US Army Medical Research and Material Command.