Effect of weekly testing on dexamethasone suppression test results in normal subjects

Stability of the dexamethasone suppression test in borderline personality disorder with and without comorbid PTSD: a one-year follow-up study

Alterations in hypothalamic-pituitary-adrenal axis feedback regulation have been repeatedly reported in patients with borderline personality disorder (BPD). Due to the cross-sectional design of these studies, little is known about the longitudinal course of HPA axis functioning. In a sample of 13 patients with BPD, the dexamethasone suppression test (DST) has been used in a one-year follow-up study. There were no changes of cortisol concentrations before or after dexamethasone intake between baseline and follow-up examination. Patients with comorbid posttraumatic stress disorder (PTSD) showed more pronounced cortisol suppression compared to those without PTSD. The DST seems to be a stable marker of alterations in HPA axis feedback regulation in BPD, which is also reflected by substantial correlations between percentage of cortisol suppression at baseline and follow-up examination.

Dexamethasone suppression test in alcohol withdrawal: relationship to depression and liver function

The relationship between dexamethasone suppression test (DST) response, depressive symptoms and liver function tests was investigated in 15 male alcohol-dependent patients for 2 weeks during alcohol withdrawal. Six of the patients relapsed into drinking within the investigation period. There was no association between DST response and relapse, which suggests that abnormal DST response has no predictive value for relapse into drinking. About 50% of the patients had abnormal DST responses during the first week of alcohol withdrawal. There was no relationship between DST response and depression or depressive symptoms. Depression remitted within 1-2 weeks, whereas DST responses remained abnormal for at least 2 weeks in 2 of the non-relapsing 9 patients. Abnormal DST response in alcohol withdrawal is unlikely to be due to alterations in liver function but may be attributable to the effect of alcohol on the hypothalamic-pituitary-adrenocortical axis.

The dexamethasone suppression test in healthy controls

We have summarized the results of 53 studies which examined the dexamethasone suppression test in normal controls. Only 3.6% of 687 0800 hr postdexamethasone cortisol levels were above 5 micrograms/dl. Corresponding figures for 1600 hr and 2300 hr cortisol levels were 7.4% (85/1144) and 6.3% (28/434), respectively. Neither the type of assay (competitive protein binding or radioimmunoassay) nor mean/median age of the subjects was associated with non-suppression rates.