Evaluation of a salivary based combined dexamethasone/CRH test in patients with major depression

The combined dexamethasone/corticotropin releasing hormone (Dex/CRH) test is one of the most reliable neuroendocrine function tests for investigation of hypothalamic-pituitary-adrenocortical (HPA) system dysregulation in depression. Persistent high HPA system activity reflected by an enhanced cortisol secretion during the Dex/CRH test after successful antidepressant treatment is correlated with an enhanced risk for relapse in remitted depressives. Thus, the Dex/CRH test might be a useful neuroendocrinological tool for treatment monitoring. However, the performance of the test requiring multiple blood samplings renders this test difficult for routine clinical use. Thus, a simplified test procedure using a saliva based test without the necessity of multiple blood samplings would be desirable.Therefore, we compared matched saliva and serum probes of Dex/CRH tests of 73 depressed patients who underwent a total of 157 tests. Both saliva and serum cortisol concentrations showed a significant stimulation pattern during the test and were highly correlated. This correlation was not influenced by either antidepressive treatment. In patients with high cortisol secretion patterns during the Dex/CRH test there was a decrease in HPA system activity after successful antidepressant treatment that was reflected by both the saliva and the serum Dex/CRH test.Thus, the saliva based combined Dex/CRH test appears to be a suitable tool for monitoring HPA system activity during the course of depressive illness. The easier performance of the saliva Dex/CRH test in comparison to the standard test procedure for both patients and hospital staff opens the door for routine clinical use of the Dex/CRH test for treatment monitoring and estimation of relapse risk.