Neuroendocrine aspects of primary endogenous depression: IX. Receiver operating characteristic analysis of the dexamethasone suppression index vs. the dexamethasone suppression test in patients and controls

The dexamethasone suppression index (DSI), which is the product of the postdexamethasone (DEX) serum DEX concentration and the post-DEX serum cortisol concentration, has been suggested to be a more sensitive discriminative test for depression than the standard DEX suppression test (DST). We used receiver operating characteristic (ROC) analysis to examine the DSI, calculated in several ways, versus the standard DST in a sample of 40 endogenous major depressives and 40 matched normal control subjects. The ROC analysis indicated that the DSI offers no advantage over the standard DST, regardless of which criterion values are used to define cortisol nonsuppression. Serum DEX determinations appear to have value primarily as an indicator of the minimum DEX concentration necessary for an accurate DST.     

Neuroendocrine aspects of primary endogenous depression: VI. Receiver operating characteristic analysis of the cortisol suppression index versus the dexamethasone suppression test in patients and matched controls

The cortisol suppression index (CSI), which is the ratio of the predexamethasone (DEX) serum cortisol concentration to the post-DEX cortisol concentration, has been investigated as an alternative means of analyzing the response of the hypothalamo-pituitary-adrenal axis to DEX. We used receiver operating characteristic (ROC) analysis to examine the CSI versus the corresponding standard post-DEX cortisol values in a sample of 40 primary endogenous major depressives versus 40 matched normal control subjects who underwent a DEX suppression test (DST). The CSI was highly correlated with post-DEX cortisol values and showed no advantage in test performance over the standard DST across a wide range of criterion values. ROC analysis is a useful technique for determining the utility of the DST and other biological markers in psychiatry.     

Plasma endogenous opioids and dexamethasone suppression test in depression

Plasma levels of beta-endorphin plus beta-lipotropin were determined in 35 hospital patients with depression and in 23 controls before and after administration of 1 mg of dexamethasone (dxm). Dxm suppressed opioid secretion in both groups. The opioid levels of the patients were significantly higher than those of the controls both before and after dxm. All the controls were cortisol suppressors. Among the patients the post-dxm opioid levels of cortisol nonsuppressors (n = 14) were higher than those of cortisol suppressors (n = 21). A significant correlation between the opioid and cortisol levels was found in the patients. There was a significant association between the use of neuroleptics and high opioid levels, but the difference between the patients and the controls was not explained by the effect of any single class of drugs. The results support the concept of hypersecretion of corticotropin-releasing factor in depression.     

The validity of the dexamethasone suppression test as a marker for endogenous depression

The validity of the dexamethasone suppression test (DST) as an indicator of endogenous depression has been most frequently tested by examining its relationship to operational criteria of endogenous depression. However, these criteria sets themselves have not been empirically validated. We examined the DST in terms of a series of hypotheses and predictions that are consistent with the theoretical construct of endogenous depression. In a consecutively admitted sample of 187 primary unipolar depressed inpatients, the DST nonsuppressors were older, had less premobid personality disorder, better social support, less frequent marital separations or divorces, fewer nonindependent stressful life events during the year prior to admission, made fewer nonserious suicide attempts during the index episode, had fewer dysfunctional attitudes, and had a lower rate of treated alcoholism and antisocial personality in their first-degree relatives. The only clearly negative finding was the lack of association between DST results and family history of depression. Our results strongly support the construct validity of the DST as a marker of endogenous depression.     

Neuroendocrine aspects of primary endogenous depression. V. Serum prolactin measures in patients and matched control subjects

To ascertain the extent of dysregulation of prolactin (PRL) secretion in endogenous depression, we determined nocturnal serum PRL concentrations and PRL responses to thyrotropin-releasing hormone (TRH), gonadotropin-releasing hormone (LHRH), and dexamethasone administration in 40 Research Diagnostic Criteria (RDC) primary, definite endogenous depressives and 40 individually matched normal control subjects. Compared to their matched controls, the patients showed no difference in basal nocturnal PRL concentrations, a marginally significant 20%-25% increase in the PRL response to TRH, and no differences in post-LHRH or postdexamethasone PRL concentrations. In the patients, there was a weak, negative correlation between age and PRL (r = -0.30), but none of the other subject characteristics or specific dimensions of depressive symptomatology were significantly related to the PRL measures. The PRL measures also were unrelated to pre- and postdexamethasone cortisol concentrations and to the thyrotropin (TSH) responses to TRH in both groups of subjects. In contrast to the previously reported hypothalamo-pituitary-adrenal cortical and thyroid axis abnormalities in these patients, our findings suggest that PRL secretion was relatively normal.     

Neuroendocrine aspects of primary endogenous depression. XI. Serum melatonin measures in patients and matched control subjects.

To ascertain the extent of dysregulation of melatonin secretion in endogenous depression, we measured nocturnal and diurnal serum melatonin concentrations in 38 depressed patients (23 women and 15 men) who had primary, definite endogenous depression according to the Research Diagnostic Criteria and in 38 individually matched normal control subjects. Previous reports have suggested that such patients may have reduced nocturnal melatonin secretion, often in conjunction with increased hypothalamic-pituitary-adrenal cortical axis activity. This has been considered as a possible reflection of reduced noradrenergic activity in depression. Compared with their matched controls, the depressed patients showed a trend toward a significantly elevated average nocturnal melatonin concentration that was accounted for primarily by the 14 premenopausal women--the postmenopausal female and male depressive patients did not differ significantly from their respective controls. The average diurnal melatonin concentration also showed a trend toward being higher in both the female and male depressed patients. The melatonin measures were not consistently related to any of the previously reported hypothalamic-pituitary-adrenal cortical axis measures in these subjects. Our findings thus failed to confirm a "low melatonin syndrome" or an inverse relationship between nocturnal melatonin and nocturnal cortisol concentrations in depression. This discrepancy may be related to methodologic differences among studies; our data are in accord with those findings of the one other reported study in which normal controls were individually matched to patients on variables that were known to influence melatonin secretion. Most of the studies, including ours, have been cross-sectional.(ABSTRACT TRUNCATED AT 250 WORDS)     

Plasma dexamethasone concentrations and the dexamethasone suppression test

Altered bioavailability or altered pharmacokinetics of dexamethasone (dex) may contribute to a positive Dexamethasone Suppression Test (DST) in psychiatric patients. We measured plasma dex and plasma cortisol concentrations in 32 patients with primary major depressive disorder (MDD), 14 patients with other psychiatric disorders, and 16 normal controls. Cortisol was measured by the competitive protein binding (CPB) assay and dex by RIA (IgG Corp.). Additionally, cortisol was measured by a fluorescent polarization immunoassay (FPIA) available on the Abbott TDx analyzer in an attempt to validate this method for use in the DST. The agreement between FPIA and CPB cortisol results was excellent. Depressed nonsuppressors, by definition, had significantly higher mean plasma cortisol concentrations than depressed suppressors, psychiatric controls, and normal volunteers at 8:00 AM, 3:00 PM, and 10:00 PM postdex. When DST nonsuppressors and suppressors were compared regardless of diagnostic group, plasma dex concentrations were significantly lower (p less than 0.01) in the DST nonsuppressors. There was a significant negative correlation between plasma cortisol levels and plasma dex levels across all subjects at 8:00 AM (r = -0.365, n = 44, p less than 0.05). When the subjects were sorted by diagnostic category, there was a strong, but not statistically significant, trend toward lower plasma dex concentrations in the melancholic nonsuppressors versus the melancholic suppressors and between the psychiatric control non-suppressors and the corresponding suppressor group. These relationships disappeared when we restricted our analyses to an empirically derived middle range of plasma dex concentrations within which the DST results were considered to be valid. We conclude that bioavailability or pharmacokinetics of dex may significantly contribute to DST results. Further investigation is needed to determine whether or not the quantification of dex and its metabolites and their determination at which specific timepoints during the DST will enhance the predictive or interpretive value of the DST in psychiatric patients.     

Neuroendocrine aspects of primary endogenous depression. X: Serum growth hormone measures in patients and matched control subjects

To determine the extent of dysregulation of growth hormone (GH) secretion in endogenous depression, we measured nocturnal serum GH concentrations and GH responses to thyrotropin-releasing hormone (TRH, gonadotropin-releasing hormone (LHRH), and dexamethasone administration in 40 Research Diagnostic Criteria primary, definite endogenous depressives and 40 individually matched normal control subjects. Compared with their controls, the patients showed no difference in basal nocturnal GH concentrations or in GH responses to TRH or LHRH. The GH measures were not significantly related to the other endocrine measures reported previously, including dexamethasone suppression test status. None of the diagnostic schemes for endogenous/melancholic depression which we studied was significantly related to the GH measures in the patients. Of the other subject and symptom variables, the mood depression factor of the Hamilton depression scale and the performance difficulty factor of the Beck depression inventory were moderately negatively correlated with the nocturnal GH measures. These findings suggest that, in contrast to the previously reported hypothalamopituitary-adrenal cortical and thyroid axis abnormalities in our patients, GH secretion was relatively normal. Patients with more severe depressed mood and greater difficulty accomplishing tasks did have moderately lower nocturnal GH values.     

Neuroendocrine aspects of primary endogenous depression VIII. Pituitary-gonadal axis activity in male patients and matched control subjects

To determine the extent of hypothalamo-pituitary-gonadal (HPG) axis dysfunction in endogenous depressed men, we measured nocturnal and diurnal serum luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone (T), and estradiol (E2) concentrations, and their responses to gonadotropin releasing hormone (LHRH) and dexamethasone administration, in 16 Research Diagnostic Criteria primary, definite endogenous male depressives and 16 individually matched male normal controls. Compared to their controls, the patients showed no differences in basal nocturnal or diurnal gonadotropin or gonadal steroid hormone concentrations, and no differences in hormone concentrations either post-LHRH or post-dexamethasone. Age was negatively correlated with baseline serum T in the patients but not in the controls, and it was modestly positively correlated with baseline serum LH in both groups of subjects. In the patients, the presence of DSM-III melancholia was modestly negatively correlated with baseline and post-LHRH concentrations of both LH and FSH and was positively correlated with baseline serum T, but it bore no relation to serum E2. None of the other subject characteristics or specific dimensions of depressive symptomatology were significantly related to the HPG axis measures. The HPG axis measures also were unrelated to pre- and post-dexamethasone cortisol concentrations in both groups of subjects. The results of this study suggest that, in contrast to the hypothalamo-pituitary-adrenal cortical and thyroid axis abnormalities frequently found in endogenous depressives, HPG axis function in male depressives is relatively normal.     

The dexamethasone suppression test and antidepressant response in major depression

We conducted a prospective open pilot study of 34 consecutively admitted patients with the DSM-III diagnosis of MD who were admitted to a general psychiatric unit. Patients underwent a 1 mg DST and were randomly assigned to treatment with either maprotiline or trazodone. Antidepressant dosages were increased as tolerated clinically and according to treatment response. Results: mean final oral doses were 193 mg for maprotiline and 328 mg for trazodone. The mean treatment duration was 4.5 weeks for maprotiline and 5.9 weeks for the trazodone group. Of these 34 patients 44% showed DST nonsuppression (41% maprotiline, 45% trazodone). Seventy-six per cent of the patients responded to treatment (76% for both drugs) as defined by GAS. Eighty-seven per cent of the nonsuppressors responded to treatment (86% maprotiline, 88% trazodone) and 68% of the suppressors responded (70% maprotiline, 67% trazodone). Of the eight treatment nonresponders six showed DST suppression. The implications of these findings are discussed.     

Situational depression and the dexamethasone suppression test

Neither baseline integrated 24 hr cortisol concentrations nor cortisol escape from dexamethasone suppression were able to distinguish a group of endogenously depressed patients who experienced precipitating events prior to their depression (situational) from a group of endogenously depressed patients with no discernible precipitating events (non-situational). Symptom severity, features of psychosis, and family history also were similar between the two groups. These results highlight the inadequacy of using the presence or absence of precipitating events for subtyping endogenous depression.     

Platelet MAO activity and the dexamethasone suppression test in bipolar depression

The correlation between postdexamethasone cortisol levels after the dexamethasone suppression test (DST) and platelet monoamine oxidase (MAO) activity was studied in 31 depressed female inpatients with Research Diagnostic Criteria primary, endogenous, bipolar depression (12 bipolar 1 and 19 bipolar 11). Out of the 31 patients, 25 showed abnormal DST results. Platelet MAO activity did not differ significantly from the matched control group. There was a trend that patients with higher MAO activity had lower postdexamethasone cortisol levels, but it was significant only for the 0800 hr cortisol levels.     

Neuroendocrine aspects of primary endogenous depression. I. Cortisol secretory dynamics in patients and matched controls

To examine both predexamethasone and postdexamethasone cortisol measures in depression, we determined circadian serum cortisol patterns, cortisol responses to dexamethasone, and 24-hour urinary free cortisol excretion before and after dexamethasone administration in 40 patients with primary, definite endogenous depression diagnosed by Research Diagnostic Criteria and in 40 individually matched normal control subjects. Fifteen patients (38%) were dexamethasone nonsuppressors; they had significantly higher predexamethasone serum and urine cortisol measures than both their matched controls and the 25 suppressor patients. Both the predexamethasone and postdexamethasone cortisol measures were unimodally distributed across the patients and the controls. Circadian cortisol rhythms of similar magnitude occurred in both groups. The cortisol measures before and after dexamethasone administration were positively correlated to a similar degree in the patients and their controls, suggesting that predexamethasone hypothalamic-pituitary-adrenocortical hyperactivity and postdexamethasone cortisol nonsuppression are not independently determined in endogenous depression.     

Age and the dexamethasone suppression test in depression

The authors examined the effects of age on plasma cortisol concentrations of 81 depressed men after dexamethasone administration. Dexamethasone nonsuppression was significantly more frequent in patients older than age 55 than those younger. Similarly, older patients had significantly higher postdexamethasone cortisol concentrations than younger patients at all time points sampled. These differences could not be attributed to severity or to the prevalence of psychosis in older and younger depressed patients.     

Ventricular size, the dexamethasone suppression test and outcome of severe endogenous depression following psychosurgery

To assess the possible significance of cerebral ventricular size and the dexamethasone suppression test (DST) in the outcome of severe endogenous depression, 28 patients were followed up and reviewed 1 year after stereotactic subcaudate tractotomy. Neither ventricular size nor the dexamethasone suppression test predicted either a good or poor outcome. There was no relationship between ventricular size and the DST results.     

The effect of serum dexamethasone concentrations in the dexamethasone suppression test

Serum dexamethasone and cortisol concentrations were measured in a sample of 98 psychiatric inpatients during the course of the 1-mg oral overnight Dexamethasone Suppression Test (DST). Suppressors were found to have significantly higher serum dexamethasone concentrations than nonsuppressors at each time of sampling (8:00 AM, 4:00 PM, and 11:00 PM). There was a significant inverse curvilinear relationship between serum dexamethasone and cortisol concentrations at each sample time. Although serum dexamethasone concentration was a potent determinant of postdexamethasone serum cortisol concentration, there were still significantly higher serum concentrations of cortisol in patients with major depression compared with patients with other disorders when dexamethasone concentrations were statistically controlled. By taking serum dexamethasone concentrations into account in defining DST suppression status, a modest increase in diagnostic specificity was achieved, but no substantial change in sensitivity.