Cortisol levels differ after the low dose dexamethasone-suppression test in outpatients and inpatients with stress related disorders as compared to healthy subjects

Abstract

Rational/statement of the problem : The low-dose dexamethasone-suppression test (DST) has originally been introduced by Yehuda et al.. Method : We here report data on the salivary cortisol responses to awakening (CAR) to the DST in healthy subjects (N=102), as well as in outpatients (N=92) and inpatients (N=99) with stress related disorders. Patient groups were matched for age and sex by propensity score matching. Stress pathology was assessed by the Patient Health Questionnaire (PHQ). Results : We observed stepwise highly significant differences among these three populations with respect to both supersuppression (< 2 nmol/l) and escape (> 6 nmol/l) of cortisol levels. Amazingly, a supersuppression was most frequently observed in healthy subjects, while an escape was most prevalent in inpatients, less common in outpatients, and rare in healthy subjects. While none of the healthy subjects got a PHQ diagnosis, inpatients and outpatients showed an average of 1.8 and 1.9 diagnoses, respectively, but did not differ with respect to the type and degree of stress pathology. Thus, the DST may rather be considered an unspecific test of dysregulations of the pituitary–adrenal axis. Conclusion : Many research studies observed a supersuppression of cortisol levels in hypocortisolemic subjects with stress related disorders, such as post traumatic stress disorder (PTSD), fibromyalgia, chronic pelvic pain. These subjects commonly express symptoms of fatigue, pain, and an enhanced stress sensitivity, but seem to be protected against deleterious effects of cortisol on organ functions. Such a protective effect may possibly explain our observation that hypocortisolemia and supersuppression are less common in inpatients and outpatients. However, the increasing number of escapes from healthy subjects to outpatients and inpatients was not unexpected. We discuss these findings by applying an additional analysis of endophenotypes.

Keywords

• cortisol response
• stress
• dexamethasone suppression
• stress-related disorders
• inpatient
• outpatient