Pharmacological and nonpharmacological factors influencing hypothalamic-pituitary-adrenocortical axis reactivity in acutely depressed psychiatric in-patients, measured by the Dex-CRH test

The most consistent biological findings in patients with depression are abnormalities in the hypothalamic - pituitary - adrenal (HPA)-axis, which can be measured using the combined dexamethasone- suppression/CRH-stimulation (Dex-CRH) test. The reactivity of the HPAaxis in this test, however, ranges over several orders of magnitude in depressed patients with comparable severity of symptoms. In this present study, we investigate which factors influence the magnitude of the response in the Dex- CRH test in 235 acutely depressed inpatients. We first examined the effects of common confounders shown to influence the HPA- axis, such as caffeine and nicotine consumption, acute stressors during the test, weight, gender, and age. Of all these variables, only female sex and nicotine consumption were positively correlated with the cortisol or ACTH response, respectively. As for the effects of psychopharmacological treatment, only the intake of carbamazepine and the fact of having relapsed under an established pharmacotherapy significantly increased the response in the Dex- CRH test, whereas the presence or absence of antidepressant treatment, the type of antidepressant treatment, or the number of ineffective antidepressant treatment trials during the index episode up to admission did not have any effect. We also found a positive correlation of the number of previous episodes, the overall HAM- D score and the severity of somatic/ vegetative symptoms with the results in the Dex- CRH test. These results underline that in depressed patients this test is not majorly influenced by disease- unrelated factors. In addition, current antidepressant treatment does not appear to affect test outcome in the absence of clinical response. The influence of the number of previous episodes and relapse under pharmacotherapy suggests that HPA- axis reactivity may be altered by repetitive states of hypercortisolemia or continuous antidepressant treatment. Finally, more severe vegetative symptoms are associated with an enhanced HPA- axis activity.