The effect of weight loss and inappropriate plasma dexamethasone levels on the DST

The dexamethasone suppression test in bulimic outpatients without major depression

Recent studies have examined the effectiveness of the dexamethasone suppression test (DST) in the evaluation of bulimia. In a series of 18 female bulimic outpatients without major depression, 9 (50%) failed to suppress on the DST. No significant difference was found between suppressors and nonsuppressors in personal and family histories of affective disorder, levels of anxious and depressive symptoms, psychoactive substance abuse, and severity of abnormal eating-related behaviours. In contrast, non-suppression was significantly associated with low weight. There is a trend to differentiate non-suppressors from suppressors in the current diagnosis of anorexia nervosa and in past history of anorexia nervosa. Seven patients received fluvoxamine for 8 weeks. Five patients were suppressors and showed a significant decrease in the frequency of their binges while the 2 non-suppressors did not improve. These preliminary results suggest that DST non-suppression might be typical of bulimic patients with anorexia nervosa and that pretreatment DST results might predict the response of bulimic behaviour to treatment with fluvoxamine.

Are depression and denutrition good predictors of dexamethasone suppression test (DST) in anorexia nervosa?

This study was conducted to investigate the corticotropic axis in anorexia nervosa. In 93 female inpatients who met DSM-III-R criteria for anorexia nervosa, subsample (n = 64) with DSM-III criteria was also considered. Using stepwise regression analysis, this study examined the relationship between independent variables ie, age, body mass index, scores on depression scales and postdexamethasone serum cortisol, considered as a dependent variable. In patients who met DSM-III criteria, 16.7% of the variance of serum cortisol can be explained. The main predictors are depressive retardation, emaciation and age. Using stepwise logistic regression the main categorical predictors of the test suppression vs non suppression are of the same nature. The condition of realisation of DST are discussed.

Dexamethasone suppression test using saliva cortisol measurement in bulimia nervosa

The assessment of cortisol in saliva has been proven a valid and reliable reflection of the respective unbound hormone in blood. In the present study, a standard dexamethasone suppression test (DST) with measures of salivary cortisol levels was performed in bulimic women without depression (DSM-IV; N=48) and healthy controls (N=24) matched for age. Feedback sensitivity was assessed using the standard DST with pre- and post-measures of salivary cortisol. Subjects were divided into suppressors and nonsuppressors according to their post-DST levels. Bulimic suppressors and nonsuppressors were compared for their basal cortisol levels, body weight (body mass index, BMI), previous episodes of anorexia nervosa, and their results in psychometric tests. A total of 16 (33.3%) out of 48 women with bulimia nervosa (BN) failed to suppress in the DST. Basal salivary cortisol levels were elevated in bulimic nonsuppressors. Significant differences between suppressors and nonsuppressors were found for body weight and previous episodes of anorexia nervosa. The results are in accordance with recent findings. They support the hypothesized association between low body weight and DST nonsuppression. Using saliva cortisol in the standard DST could be advantageous for studying bulimic patients. Furthermore, the results show the importance of determining HPA reagibility when measuring cortisol in bulimic patients.

The lower limits of dexamethasone window in Chinese depressives

BACKGROUND

Previous studies have shown wide variation in plasma dexamethasone (DEX) concentrations following a standard 1-mg dexamethasone suppression test (DST), and significantly lower DEX concentrations in DST nonsuppressors compared with suppressors, suggesting that DEX pharmacokinetics/bioavailability is an important variable associated with DST nonsuppression.

METHODS

To determine the effect of plasma DEX levels on the DST in Chinese depressives, we measured plasma DEX and post-DEX cortisol levels at 4:00 PM in a group of 50 depressed outpatients, 28 anxiety outpatients, and 33 normal subjects during the course of 1-mg oral overnight DST.

RESULTS

We found a significant difference in the plasma DEX levels between DST nonsuppressors and suppressors in the depression group and overall subject population, and a significant negative correlation between the plasma DEX and cortisol levels in the depression, anxiety, and total groups. Within a DEX "window", the DST performance was enhanced, whereas the relationships between plasma DEX and post-DEX cortisol levels remained equally strong.

CONCLUSIONS

Our findings support a relationship between plasma DEX and post-DEX cortisol levels, a relationship that might be superimposed on the hypothalamic-pituitary-adrenal axis. Comparing our "window" range with those of previous studies, we suggest that Chinese depressives may have lower limits of plasma DEX window, and that ethnicity may be an intervening variable in both DST response and pharmacokinetics of DEX.

Disturbances in the hypothalamo-pituitary-adrenal and other neuroendocrine axes in bulimia

Disturbances in the hypothalamo-pituitary-adrenal (HPA) and other endocrine axes were assessed in 24 women with bulimia and healthy controls. Overnight blood samples for measuring nocturnal plasma cortisol, prolactin (PRL), growth hormone (GH), luteinizing hormone (LH), and follicle stimulating hormone (FSH) were obtained at 30-min intervals. A 1.5 mg dexamethasone suppression test (DST) and a TRH-test were performed. Patients were monitored closely while their nutritional intake was recorded over 21 days. Compared with healthy controls, nocturnal cortisol plasma levels were not elevated in the bulimics. There was a trend toward insufficient cortisol suppression in the DST in patients with bulimia, which was most pronounced in patients with signs of restricted caloric intake. Plasma dexamethasone levels were significantly reduced in bulimics compared with healthy controls. There was a trend for blunted thyrotropin stimulating hormone (TSH) responses to thyrotropin releasing hormone (TRH) in bulimia. The prolactin response to TRH was significantly reduced in bulimics with a history of anorexia nervosa. Plasma LH and plasma FSH were significantly reduced in bulimics with signs of reduced caloric intake [low T3, high levels of beta-hydroxy-butyric acid (BHBA), reduced daily caloric intake, high number of fasting days] as compared with healthy controls. Bulimics with high BHBA levels had significantly reduced nocturnal prolactin plasma levels. Results show that multiple neuroendocrine disturbances exist in bulimia in a milder form than in anorexia nervosa. Evidence for the impact of caloric intake on endocrine functions is presented. Endocrine dysfunctions in our bulimic sample did not show a positive association with the presence of depressive symptoms.

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.

Dexamethasone kinetics in depressed patients before and after clinical response

Dexamethasone pharmacokinetics were measured in 19 depressed patients, 10 dexamethasone suppression test (DST) nonsuppressors and nine suppressors, following a 1 mg oral dose in tablet form at 2300 h. Median dexamethasone concentrations were significantly lower in the nonsuppressors from 3-16 hr post-administration. Nonsuppressors had a significantly lower area under the curve than suppressors, and plasma clearance was significantly faster in the nonsuppressors than in the suppressors. Eleven patients, six nonsuppressors and five suppressors, agreed to a repeat DST after clinical improvement when all six nonsuppressors had normal DST responses. There were no significant differences between the median dexamethasone concentrations, or any of the pharmacokinetic parameters measured, of the "normalising" nonsuppressors and the suppressors. Dexamethasone kinetics were altered in depressed nonsuppressors but became normal with remission of depressive symptoms and normalisation of the DST response.

Pharmacoendocrinology of major depression

Major depressives often have abnormalities in the secretion patterns of their anterior pituitary hormones and target endocrine gland hormones. There are changes in both basal hormone secretion and the responses of these hormones to perturbation tests. Considerable work has been done attempting to develop a clinical application for some of these changes as biological state markers of endogenous depression. Prominent among the changes is an overactivity of the hypothalamo-pituitary-adrenocortical (HPA) axis. The dexamethasone suppression test (DST), as a reflection of HPA axis activity, has been the most thoroughly investigated "biological test" in psychiatry to date. Considerably fewer studies have addressed more fundamental issues of HPA axis regulation in depression, such as the relationship between pre-DST cortisol hypersecretion and DST outcome. The next most widely investigated endocrine axis in depression has been the hypothalamo-pituitary-thyroid (HPT) axis. Most studies have dealt with the TSH response to exogenously administered thyrotropin releasing hormone. While blunted TSH responses have been found in depressives compared with normal controls, the frequency of blunted responses in other types of psychiatric patients has made this test marginally useful for differential diagnosis. The reported changes in other hormone axes, for example the blunted growth hormone response to several challenges noted in depressed patients, have not been investigated sufficiently thoroughly to support their general clinical use at present.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of age on cortisol and plasma dexamethasone concentrations in depressed patients and controls

The aim of this study was to identify any relationships between various patient factors such as age, gender and concurrent medication that may affect plasma cortisol or dexamethasone (DEX) concentrations. Multiple regression analysis was used to formulate an equation to predict plasma DEX levels to identify factors that may influence DEX bioavailability. Pre- and post-DST cortisol levels did not increase with age, but DEX levels were higher in elderly depressed patients. Neither gender nor psychotropic medication affected plasma cortisol or DEX levels. There was no indication that pre-DST cortisol levels influenced plasma DEX levels to account for the lower DEX values in non-suppressors. Age was the only significant factor found in this study to influence DEX levels and it could be argued that the dose of DEX should be lowered when administering the DST to elderly patients to reduce plasma DEX variability.

The significance of HPA axis disturbance in panic disorder

Agoraphobic and panic disorder patients underwent 1-mg Dexamethasone Suppression Tests (DST) before, during, and after an 8-week trial of diazepam, alprazolam, or placebo. Previously described, never-ill controls underwent similar testing. At baseline, 21 of 82 (25.6%) panic disorder and 5 of 38 (13.2%) controls were nonsuppressors. This difference grew more marked with multiple testing over a 2-month period; 18 of 44 (40.9%) panic disorder patients were nonsuppressors on at least 1 of 3 tests compared with only 5 of 35 (14.3%) controls (p = 0.006). DST results were related to severity, but not to the presence or absence, of depressive syndromes. Control for plasma dexamethasone levels left highly significant differences in postdexamethasone cortisol across diagnostic groups. Neither DST results nor plasma dexamethasone levels changed in concert with clinical change, and type of treatment had little differential effect on these measures. Nor did DST results predict subsequent course when active treatment was extended by 6 months. However, DST results during the initial 8 weeks of treatment were strongly related to relapse when medications were tapered, even though this occurred 6 months after the last DST.

Specificity of the salivary cortisol dexamethasone suppression test across psychiatric diagnoses

One hundred forty-eight psychiatric inpatients, 12 outpatients, and 17 normal controls were given the 1.0-mg overnight Dexamethasone Suppression Test (DST), with salivary cortisol concentrations being measured as the dependent variable. Based on the Structured Clinical Interview for DSM-III, the patients were diagnosed as having major depression with melancholia (n = 21), nonmelancholic major depression (n = 50), mania (n = 15), schizophrenia (n = 32), dementia (n = 6), substance dependence/abuse n = 18), and miscellaneous (n = 18). Neither the melancholic major depressives nor the entire group of major depressives had significantly higher salivary cortisol pre- or postdexamethasone as compared with all the other patients combined, nor did the melancholic patients have significantly higher cortisol than the nonmelancholic depressives. The inpatients as a group had significantly higher pre- and postdexamethasone cortisol values than the normal controls; cortisol values for the outpatients were intermediate between these two groups. Illness severity (in the depressives), length of time in hospital before the DST, and medication regimen were all unrelated to DST outcome. Thus, in this study, the salivary cortisol DST showed little clinical utility in discriminating major depressives with and without melancholia from other patients with a broad range of psychiatric diagnoses. The test did distinguish between hospitalized psychiatric patients and normal control subjects and between depressed inpatients and depressed outpatients, indicating that hospitalization-related variables contributed to DST outcome.

Plasma dexamethasone and cortisol levels in depressed outpatients

We investigated the 1-mg dexamethasone suppression test (DST) in 41 outpatients with major depressive disorder assessing the role of dexamethasone blood level, age and basal cortisol on DST results. Non-suppressors (approximately 25% of patients) had lower dexamethasone levels, and post-dexamethasone cortisol was negatively correlated with plasma dexamethasone; these findings were more significant after covarying out age and basal cortisol, factors that were also significantly associated to non-suppressors. A subgroup of patients (n = 19) also had 0.75-mg and 2.0-mg DST to evaluate whether a threshold dexamethasone blood level existed; a dexamethasone blood level greater than 1.5 ng/ml converted all non-suppressors to suppressors. Implications of these findings are discussed.

The DST and TRH test in bulimia nervosa

Abnormal neuroendocrine responses have been found in depression and eating disorders. It remains unclear whether these reflect an underlying shared biology or epiphenomena. To evaluate this further, we conducted the 1 mg DST and the TSH response to 500 micrograms i.v. TRH in normal-weight bulimics and controls. Bulimics (n = 18) demonstrated significantly more DST non-suppression (45%) than controls (18%; n = 20). In the bulimic group, non-suppressors were significantly thinner than suppressors, but did not differ from them on any measure of depression. Bulimics (n = 19) and controls (n = 12) responded similarly without blunting on the TSH response to TRH. These data suggest that DST non-suppression may be related to non-specific variables such as weight. Bulimics do not demonstrate TSH blunting as found in some depressed patients. These tests do not support evidence for a biological link between these disorders.

Judgement of the hypothalamic-pituitary-adrenocortical function in psychiatric patients by betamethasone-induced cortisol suppressibility

Betamethasone induced cortisol suppressibility was examined in 62 drug free consecutively admitted psychiatric inpatients. Betamethasone was choosen instead of the commonly used dexamethasone, because its double half-life compared to dexamethasone and its higher tissue availability. After a base-line evaluation with blood samples drawn at 8 a.m., 4 p.m., and 11 p.m., 0.5 mg or 1.0 mg betamethasone was given orally at 11 p.m. Postbetamethasone cortisol as well as betamethasone blood levels were then measured at the same time points as on the baseline day. In the groups receiving 1.0 mg betamethasone non-depressed patients had significantly (p less than 0.05) lower postbetamethasone cortisol levels than depressed patients for each time point measured whereas 0.5 mg betamethasone did not differentiate depressed from non-depressed patients. Patients with other depressions like schizoaffective psychosis-depressive subtype- or organic brain syndrome with depressive symptomatology demonstrated similar postbetamethasone cortisol profiles as the group of patients with major depression. Betamethasone plasma concentrations differed significantly (p less than 0.001) with respect to the oral dosage with higher values for the 1.0 mg betamethasone groups.

Cortisol suppression per nanogram per milliliter of plasma dexamethasone in depressive and normal subjects

It has been suggested that dexamethasone pharmacokinetics may affect cortisol suppression during the Dexamethasone Suppression Test (DST). In depressed patients the cortisol response has been shown to negatively correlate with dexamethasone plasma concentrations, which also influence the sensitivity and specificity of the DST. These findings have been interpreted as weakening the utility of the DST. However, the analysis of pre- and post-1 mg DST cortisol concentrations corrected for plasma dexamethasone concentrations suggest that compared with normals (n = 52), patients with major depressive disorder (MDD) as a group (n = 71) had less suppressibility of cortisol to the same plasma dexamethasone concentrations. Moreover, when the MDD patients were evaluated based on DST status, the suppressors had cortisol/dexamethasone ratios (micrograms/dl of cortisol per ng/ml of plasma dexamethasone) similar to the normal controls, whereas the nonsuppressors had ratios that were significantly higher. These data suggest that DST non-suppression, as well as sensitivity and specificity of the DST in depression, is not only attributable to altered dexamethasone disposition, but indeed, there is a genuine reduced sensitivity of cortisol to dexamethasone that still points to an abnormality of the delayed feedback mechanism of the hypothalamic-pituitary-adrenal system in some depressed patients.

The dexamethasone suppression test in relation to symptomatology: preliminary findings controlling for serum dexamethasone concentrations

A diagnostically heterogeneous sample of psychiatric inpatients (n = 52) was administered the 1 mg dexamethasone suppression test (DST) shortly after hospital admission. Each was also assessed using the Hamilton Rating Scale for Depression (HRSD) and selected items of the Present State Examination (PSE) representing psychomotor retardation and anxiety. A potent determinant of postdexamethasone serum cortisol concentrations was found to be the level of serum dexamethasone concentration achieved following the oral dose. No relationship was found between postdexamethasone cortisol concentration and the scores on either the HRSD or an anxiety scale derived from selected PSE items. However, symptoms of psychomotor retardation were significantly related to postdexamethasone serum cortisol concentration, particularly when the serum dexamethasone concentrations were taken into account. It may be that DST nonsuppression in psychiatric patients is in part a reflection of the presence of psychomotor retardation, a phenomenon that cuts across diagnostic categories.

Past and present strategies of research on the HPA-axis in psychiatry

Hypercortisolism in depression has been extensively studied during the last three decades. The main hypothesis regarding origin and clinical relevance of this phenomenon, however, has changed significantly. Up to the mid-seventies hypercortisolism was conceived as consequence of stress modified by the degree of unconscious defense mechanisms in different forms of depressive or non-depressive psychiatric disorders. At the end of the seventies this point of view changed considerably. Hypercortisolism was regarded as a biological statemarker of the endogenous subtype of depression with clinical differential-diagnostic relevance. An abnormal dexamethasone suppression test (DST) was assumed to be the best indication of increased activation of the cortisol system. These conclusions turned out to be wrong. DST results are not specific for melancholia and the test seems to be of limited value for measuring the function of the HPA-axis. Intervening variables, such as weight loss, drug and alcohol withdrawal or situational stress, influence the test results significantly, independent of the nosological classification. Additionally, interindividual differences in the susceptibility of the HPA-axis may decisively influence the the activation of the HPA-axis as well in healthy subjects under stress as in psychiatric patients.

Plasma dexamethasone and the dexamethasone suppression test. Initial and follow-up tests in depressed patients

Plasma dexamethasone concentrations following oral dexamethasone administration were examined in 78 patients with major depression prior to and during treatment. The test-retest stability of plasma dexamethasone levels within patients was satisfactory with an overall significant positive correlation between tests for each patient. However, significant variability was noted in individual patients. Change in pre-DST cortisol and plasma dexamethasone levels were the two variables, in that order of importance, contributing to change in DST status. In studies examining the clinical utility of serial dexamethasone suppression tests as a guide to recovery from depression, the effect of variability in plasma dexamethasone concentrations should be taken into account.

Serum dexamethasone concentrations in endogenous depressives before, during, and after treatment: preliminary observations

The 1.0-mg Dexamethasone (DEX) Suppression Test (DST) was performed in 10 endogenous depressives prior to treatment, during treatment, and again when the patients were medication- and symptom-free. Five of the 10 patients were DST escapers prior to treatment, and all 10 patients were DST suppressors following treatment. During treatment, 6 patients were DST escapers, 2 of them having been suppressors initially. There were no significant differences in serum DEX concentrations before, during, and after treatment in either the 5 DST escapers or the 5 DST suppressors. These results lend further support to the concept that reduced serum DEX concentrations are not the major factor underlying DST nonsuppression.

The effects of dieting and weight loss upon the stimulation of thyrotropin (TSH) by thyrotropin-releasing hormone (TRH) and suppression of cortisol secretion by dexamethasone in men and women

The effects upon basal hormone levels and neuroendocrine responses of a weight reducing diet allowing 1200 kcal daily were determined in male and female volunteers. Thyrotropin (TSH) responses to thyrotropin-releasing hormone (TRH) were unchanged in men but attenuated in women; this effect was associated with a fall in basal TSH in women, not in men. Rates of non-suppression of cortisol in response to oral dexamethasone (1 mg) were unchanged during dieting although basal morning cortisol levels rose in males and females. The implications for the use of the TRH test and the dexamethasone suppression test (DST) in depressive illness are discussed.

The dexamethasone suppression test and plasma dexamethasone in generalized anxiety disorder

A Dexamethasone Suppression Test nonsuppression rate of 27% was found in a group of 30 generalized anxiety disorder patients before treatment. The dexamethasone concentrations in the eight nonsuppressors were significantly lower than in eight suppressors matched by sex and age, but were similar to those in five nonsuppressors from a matched normal control group. The dexamethasone concentrations in the generalized anxiety disorder suppressors and a matched group of eight normal control suppressors were similar. After successful nondrug behavioral treatment, all generalized anxiety disorder patients were suppressors. Posttreatment dexamethasone concentrations in the initial nonsuppressor patients remained significantly lower than in the initial suppressors. The results suggest that low plasma dexamethasone concentrations after 1 mg oral dexamethasone may confer a vulnerability to nonsuppression that may be expressed in the presence of high state anxiety.

Plasma dexamethasone kinetics during the DST after oral and intravenous administration of the test drug

We compared early biophase kinetics of dexamethasone in 33 patients with a major depression who received a DST either by an oral (n = 20) or an intravenous (n = 13) route. After an oral DST, the dexamethasone kinetics between 14 suppressors and 6 nonsuppressors were indistinguishable during the early distribution phase. However, elimination of dexamethasone from the circulation was significantly enhanced in DST nonsuppressors, resulting in an association of decreased plasma dexamethasone with elevated post-DST cortisol levels. Following intravenous DST administration, we identified 5 nonsuppressors and 8 suppressors whose plasma dexamethasone kinetics were indistinguishable, and during the elimination phase, were in the same order of magnitude as those of nonsuppressors after an oral DST. We suggest that the actual plasma concentration at the conventional post-DST sampling times does not reflect the biopotency of the test drug to suppress the pituitary adrenocortical activity. Plasma dexamethasone concentrations after an oral DST that were associated with nonsuppressed cortisol seem to be coherent phenomena of the underlying endocrine disturbance, the precise nature of which deserves further study.

Interindividual differences in the susceptibility of the cortisol system: an important factor for the degree of hypercortisolism in stress situations?

Whereas in psychophysiological research, the specificity of the individual responses has been assumed to be an important trait variable influencing the investigated parameters in stress experiments or in psychopathological states, in psychoneuroendocrinology, the individual differences in the susceptibility of the investigated neuroendocrine axes have been widely neglected. The present study on the cortisol response of 12 healthy young men to 5 different stress tests is considered to be an initial orientation step into this field. All five stress tests (quiz, arithmetic tasks, stress film, cold pressor test, and physical exercise test) could be proven to be effective stimuli regarding the cortisol system. There was, however, a broad spectrum of cortisol responses among the 12 subjects, with a continuum between complete reactors and nonreactors. This did not correlate with the subjective judgment of stress at all. Although the data showed a tendency toward an augmented dispersion of the response frequencies in comparison with random variation, the limited sample size of subjects and stress tests did not allow a statistically significant proof of a stimulus-independent, individual response specificity. Further experimental clarification seems to be necessary to avoid misinterpretations of neuroendocrine data in psychiatric disorders due to neglect of this variable.

The dexamethasone suppression test: importance of dexamethasone concentrations

Plasma dexamethasone concentrations and cortisol response to dexamethasone were measured in 29 normal healthy volunteers, 23 depressed patients, and 10 patients with anorexia nervosa at 4:00 PM postdexamethasone. In each of the 3 groups, nonsuppressors had lower dexamethasone concentrations than suppressors. Of the subjects with plasma dexamethasone at or below 0.7 ng/ml, a significantly higher proportion (48%) were nonsuppressors compared to the proportion above 0.7 ng/ml (14%), all of whom were patients. Plasma dexamethasone concentrations in a subgroup of depressed nonsuppressors were high (mean 1.35 ng/ml), whereas the remainder were low (0.42 ng/ml) and were similar to the normal nonsuppressors (0.35 ng/ml), suggesting different mechanisms for nonsuppression in the subgroups. Plasma dexamethasone concentrations were similar in nonendogenous and endogenous depressives, in men and women, and in medicated and drug-free patients. None of the variables of age, weight, history of weight loss, Hamilton depression rating score, predexamethasone cortisol, or postdexamethasone cortisol were significantly correlated with plasma dexamethasone, except for body weight and a history of weight loss in the depressed group only. Mean plasma dexamethasone concentrations increased significantly from week 1 to week 2 in 7 depressed patients, whereas plasma cortisol decreased; however, the relationship between dexamethasone and cortisol varied considerably for individual patients.

Weight loss, cortisol levels, and dexamethasone suppression in major depressive disorder

Appetite and/or weight loss are integral, albeit not necessary, symptoms of depression. We explored the contribution of diminished appetite and/or weight loss ascertained by history to the hypothalamic-pituitary-adrenocortical (HPA) axis dysregulation in 120 patients with primary major depressive disorder. Significant positive relationship for both appetite and weight loss with cortisol levels in plasma and cerebrospinal fluid (CSF) were observed. Plasma cortisol levels were consistently higher in patients who noted both appetite and weight loss as opposed to patients without appetite or weight loss. Depressed patients with weight loss showed higher rates of dexamethasone-nonsuppression. Age and severity of depression influenced but did not eliminate the significance of the findings, suggesting that weight loss accounts in part for the HPA-axis function changes observed in depression.

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.

Multisteroid analysis after DST in depressed patients--a controlled study

111 consecutively admitted in-patients with a depressive syndrome received a dexamethasone suppression test (DST) after all known factors which might confound the test results had been carefully excluded. Plasma concentrations of cortisol, corticosterone and dexamethasone were compared with several diagnostic evaluations (RDC, DSM-III, ICD-9) in a controlled study. The positive predictive value of nonsuppressed corticosteroid levels was only moderate for each diagnostic category. Diagnostic specificities were 84.6% for major depression, endogenous subtype (RDC), 71.2% for melancholia (DSM-III) and 86.8% for endogenous depression (IDC-9) when using a post-DST cortisol value above 50 ng/ml (5 micrograms/dl) as the referent value to define DST nonsuppression. Combined determination of cortisol and corticosterone as an index of dexamethasone-induced suppression raised the sensitivity rate considerably at the cost of the predictive value for major diagnostic categories. Dexamethasone plasma levels were reciprocally correlated with cortisol levels and neglect of samples with low plasma dexamethasone contents improved the diagnostic performance for endogenous depression according to RDC and ICD-9, but not for DSM-III melancholia. Although it would be speculative to suppose that the observed low dexamethasone levels are involved in DST nonsuppression, the present findings emphasize that multisteroid analysis which includes dexamethasone is important in future studies designed to explore the clinical utility of the DST.

Weight loss causes neuroendocrine disturbances: experimental study in healthy starving subjects

A variety of endocrine dysfunctions have been reported for anorexia nervosa, protein caloric malnutrition, and depression. The effect of reduced caloric intake and weight loss on endocrine functions was assessed in an experiment with five healthy female subjects during an initial baseline phase, a 3-week phase of complete food abstinence, weight gain to the original level, and a final baseline phase. During fasting, disturbances in hypothalamic-pituitary-adrenal function were observed, with elevated plasma cortisol levels, increase in the number of secretory episodes, increase in cortisol plasma half-life, and insufficient suppression following 1.5 mg dexamethasone. While all dexamethasone suppression tests (DSTs) were normal at baseline, 7 of 14 DSTs showed insufficient suppression in the fasting phase. During fasting, basal thyroid-stimulating hormone (TSH) values were lowered and the TSH response to thyrotropin-releasing hormone (TRH) was blunted. The plasma level of growth hormone (GH) over 24 hours was elevated during fasting and administration of the alpha 2-adrenergic receptor agonist clonidine resulted in a subnormal GH response after restoration of original body weight. One of the five subjects showed increased irritability, distress, anxiety, and depression as measured by various psychological scales. The results show that reduced caloric intake, weight loss, or catabolic state have powerful effects on several endocrine systems. The specificity of measures of endocrine disturbances (DST, TRH tests, and clonidine tests) as biological markers for certain types of depression must be questioned, and the metabolic state should be given more consideration in future studies.

The limited utility of the dexamethasone suppression test for the diagnostic process in psychiatry

In 231 psychiatric in-patients, the 1 mg or 1.5 mg DST with blood samples at 0900 h, 1600 h and 2300 h and a post-dexamethasone plasma cortisol threshold of greater than or equal to 5 micrograms/dl were tested for their differential diagnostic utility in clinical psychiatry. Neither test significantly separated endogenous depressed patients from patients with other depressive or non-depressive psychiatric disorders. Studies of the 1 mg or 1.5 mg DST in 75 healthy subjects revealed about 12% of cortisol non-suppressors, when a post-dexamethasone cortisol threshold of greater than or equal to 5 micrograms/dl was used. This seemed to be an unacceptably low specificity of the test in normal subjects. A threshold criterion of greater than or equal to 8 micrograms/dl, however, yielded only 2.7% of non-suppressed normal subjects. Analyses of the DST data of the psychiatric patients, using a cortisol threshold of greater than or equal to 8 micrograms/dl, also failed to reveal a significantly higher specificity of the DST for endogenous depression. However, it was demonstrated that intervening variables such as stress due to hospital admission, drug withdrawal, suicidal turmoil, weight loss, as well as a low dexamethasone plasma level, enhance the rate of abnormal DST results in psychiatric in-patients, regardless of their diagnostic classification.