Wahbeh H, Oken BS. Salivary cortisol lower in posttraumatic stress disorder. (2013) J Trauma Stress, 26(2):241–248. doi:10.1002/jts.21798
Altered cortisol has been demonstrated to be lower in posttraumatic stress disorder (PTSD) in most studies. This cross-sectional study evaluated salivary cortisol at waking, 30 minutes after, and bedtime in 51 combat veterans with PTSD compared to 20 veterans without PTSD. It also examined the relationship of cortisol to PTSD symptoms using two classifications: DSM-IV and the more recent four-factor classification proposed for DSM-V. The PTSD group had lower cortisol values than the control group (F(6, 69) = 3.35, p = .006). This significance did not change when adding age, body mass index, smoking, medications affecting cortisol, awakening time, sleep duration, season, depression, perceived stress, service era, combat exposure, and lifetime trauma as covariates. Post-hoc analyses revealed that the PTSD group had lower area under the curve ground and waking, 30min, and bedtime values while the cortisol awakening response and area under the curve increase were not different between groups. The four-factor avoidance PTSD symptom cluster was associated with cortisol but not the other symptom clusters. This study supports the finding that cortisol is lower in people with PTSD.