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

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 effect of diagnosis and age on the DST: a metaanalytic approach

The authors present new data on the results of the pretreatment Dexamethasone Suppression Test (DST) in 164 drug-free inpatients, as well as on the effects of age on postdexamethasone cortisol values. Nonsuppression rates were 18% in schizophrenic patients (n = 44), versus 46% in patients with a major depression (n = 56). In addition, a significant correlation was found between age and the 4:00 PM postdexamethasone cortisol value among the depressed patients (r = 0.33). The authors then applied a metaanalysis to summarize 25 other studies that have addressed the schizophrenia/major depression dichotomy as it relates to the DST outcome. Nonsuppression rates were consistently different in schizophrenic patients (19%) when compared to patients with a major depression (51%) or normal controls (7%). These differences were highly significant as measured by the Mantel-Haenszel chi-square statistic. A metaanalysis applied to a series of correlations obtained from 14 other studies reporting an age/postdexamethasone cortisol relationship in affective patients indicated a modest, but significant correlation (r = 0.24) in a total of 1284 patients (p less than 1 x 10(-8)).

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.

Lack of correlation between DST results and urinary MHPG in depressed inpatients

Abnormalities of noradrenaline metabolism and of the activity of hypothalamic-pituitary adrenal axis (HPA) have been reported in depression. To study the possible relationship between these 2 parameters, urinary excretion of 3-methoxy-4-hydroxy-phenylethyleneglycol (MHPG) and Dexamethasone Suppression Test (DST) were analyzed in 58 depressed patients. A positive correlation was found between the age of depressed patients and 24-h urinary excretion of MHPG. Twenty-two patients (38%) were DST non suppressors. Pre-DST plasma cortisol levels were significantly higher in non suppressors than suppressors. No difference was found however between urinary MHPG levels in suppressors and non suppressors. There was no correlation between pre-DST plasma cortisol and levels of urinary excretion of MHPG. These results do not support the hypothesis of a relationship between these 2 parameters. However, when depressed patients were separated into two groups according to urinary excretion of MHPG ("high MHPG" and "low MHPG"), the "high MHPG" group included significantly more non suppressors then the "low MHPG" one. This result is not sufficient to demonstrate of link between HPA system activity and central noradrenaline metabolism.

Dexamethasone suppression test and response to antidepressant therapy in psychogeriatric patients

Senile dementia patients show a high incidence of abnormal Dexamethasone Suppression Test (DST) which has been suggested to reflect the presence of atypical or subclinical depression; this study was designed to test this hypothesis. Thirty-six patients, diagnosed as suffering from dementia and/or depression on the DSM-III criteria, participated in the study. They were divided into three groups. dementia (12), depression (12) and dementia with depression (12). The results indicated that although patients with depression alone responded well to antidepressant therapy, no improvement occurred in patients with dementia. Demented patients who had clinical depression also showed a poor response. The response to treatment was unrelated to the DST status of the patients. It is concluded that abnormal DST in dementia patients is not indicative of a masked affective state, and antidepressants have no place in the management of dementia patients who have a positive DST but no overt affective symptoms.

Anxiety and the dexamethasone suppression test monitored with saliva

To assess the effect of anxiety on response to the Dexamethasone Suppression Test (DST), cortisol concentrations were determined in patients who had various diagnoses, with anxiety as a secondary characteristic. Saliva was collected before and after venepuncture at 4:05 PM following completion of the Leeds Questionnaire at 3:00 PM. Matrix effects, which caused an initial artefactual decrease in cortisol levels in some saliva samples in patients with high anxiety, could be eliminated by repeated freezing/thawing. There was no significant difference between salivary cortisol concentrations before and after venepuncture, indicating that variability in response to the DST is not a correlate of anxiety and stressful venepuncture. There was no association between anxiety scores and plasma or salivary cortisol values: thus, anxiety is unlikely to be a major contributory cause of nonsuppression of hypercortisolemia in the DST.

Performance of the dexamethasone suppression test in depressive illness according to ICD and DSM-III classification systems

The performance of the dexamethasone suppression test was assessed in 90 consecutive admissions with a diagnosis of depression, categorised according to two classification systems (DSM-III and ICD-9). Non-suppression was found in most of the diagnostic categories, but there was a highly significant association with the DSM-III classification 'major depressive episode with melancholia' (52%) in comparison with the ICD group 'manic-depressive illness-depressed' (29%).

Cortisol, ACTH, and dexamethasone concentrations in a psychogeriatric population

Cortisol and adrenocorticotrophic hormone (ACTH) were measured at 2 time points before the administration of 1 mg of dexamethasone (day 1) and 1 time point on the following day (day 2). Thirteen severely depressed elderly patients, 15 patients with Alzheimer-type dementia (ATD), and 16 normal controls were studied. Cortisol was markedly elevated in depressed patients compared with the other subjects in day 1 samples. Following dexamethasone, both the depressed and ATD patients showed a similar elevation of cortisol compared with controls. ACTH concentrations were not significantly different between the groups before dexamethasone, but were significantly higher in both depressed and ATD patients after dexamethasone. More depressed patients than ATD patients exhibited hypersecretion of ACTH after dexamethasone. This implies that ACTH is less responsive to glucocorticoid feedback in elderly depressed patients, which may be a factor in causing hypercortisolemia.

Methodological aspects of hCRF-stimulated ACTH and cortisol secretion in healthy subjects

This study, aimed at clarifying some methodological problems of the hCRF stimulation test, was performed on 12 healthy male volunteers. ACTH and cortisol increases after 30 min and their maximum increase proved to be highly reliable response parameters for the net area under the response curve of both hormones. An influence of baseline hormone values on the maximum response was apparent for cortisol but not for ACTH. Cortisol, but not ACTH, revealed a stable test-retest reliability. There were no correlations between ACTH and cortisol responses to hCRF.

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.

Psychobiology of anorexia nervosa

The psychobiology of anorexia nervosa is described and explained under four headings; (1) the psychopathology as related to the motivation for fasting; (2) metabolic and somatic consequences of starvation, including brain morphology; (3) endocrine abnormalities in the hypothalamic-pituitary-adrenal and gonadal axis; and (4) the hunger drive and its possible perversions in terms of aspects of neuroethology and the reward system in the brain.

REM sleep and cortisol response to the cholinergic challenge with RS 86 in normals and depressives

The influence of the muscarinic agonist RS 86 on rapid-eye-movement (REM) sleep and on hypothalamic-pituitary-adrenocortical (HPA) axis was studied in healthy subjects and in patients with a major depression. In both groups, RS 86 induced a shortening of REM latency and an increase in REM sleep; these effects were more pronounced in the depressives than in the controls. This finding supports the assumption that in depression the REM sleep regulating neurons are hypersensitive to cholinergic stimuli. However, neither in the healthy subjects nor in the depressed patients was an RS 86 induced increase in plasma cortisol seen. This observation does not agree with the assumption that, in humans, the HPA axis is stimulated by muscarinic neurons and that hypercortisolemia in depression is due to an overactivity of muscarinic neurons activating the HPA axis.

Relationship between the dexamethasone suppression test and the L-tryptophan/competing amino acids ratio in depression

Levels of L-tryptophan (L-TRP), of the competing amino acids (CAA) valine and leucine, and of postdexamethasone cortisol taken at 8 a.m., 4 p.m., and 11 p.m. were determined in serum samples from 140 depressive patients. The relationships between postdexamethasone cortisol values, the CAA, and the L-TRP/CAA ratio were assessed using Pearson and Spearman correlation coefficients and multiple regression. There was a significant correlation between postdexamethasone cortisol and both L-TRP and the L-TRP/CAA ratio. The highest correlation coefficients were obtained for the 8 a.m. cortisol values. Nonsuppressors, in comparison with suppressors, showed a significantly lower L-TRP value and L-TRP/CAA ratio.

Prolactin response to dexamethasone: a study on normal controls and depressed patients

Pre- and post-dexamethasone prolactin and cortisol levels of 40 endogenous and non-endogenous depressive patients and of 20 controls were studied. Dexamethasone had a suppressive effect on prolactin levels, which was expressed more in normal controls and in non-endogenous depressive patients than in endogenous depression. A "prolactin suppression test" by dexamethasone was constructed and provided comparable results to the usual DST. However, it failed to be a specific marker for endogenous depression. There are close relationships between various endocrine axes, which might be altered in depression.

Dexamethasone suppression test in severe schizophrenic illness: effects of plasma dexamethasone and caffeine levels

A dexamethasone suppression test (DST) was administered to 31 inpatients with a severe acute schizophrenic exacerbation 4 or 5 days following admission and repeated after 4 weeks or prior to discharge. We identified 15 patients (48%) who were nonsuppressors on the DST at the first test. To exclude major confounders of DST results we monitored weight constancy and plasma concentrations of dexamethasone. In a subgroup of patients also plasma caffeine contents were determined. Our results indicate that DST nonsuppression occurs frequently among patients with schizophrenic crisis. Since caffeine plasma levels were indistinguishable between suppressors and nonsuppressors we reject that excessive caffeine intake accounts for DST nonsuppression among individuals with schizophrenia. Nonsuppressors had lower plasma dexamethasone levels than suppressors and reversal of the DST status from nonsuppression to suppression was associated with an increase of plasma concentrations of the test drug.

A combined study of cortisol, ACTH and dexamethasone concentrations in major depression. Multiple time-point sampling

The pathophysiology of hypercortisolaemia in major depression was examined. ACTH was measured using a novel immunoradiometric assay of high specificity and sensitivity. Twenty-eight patients with major depression and 18 control subjects were studied. Blood samples for basal hormone concentration were taken at 09:00, 16:00 and 23:00 on day 1, followed by administration of 1 mg dexamethasone at 23:00. Further samples were taken at 09:00 and 16:00 on day 2. Dexamethasone concentration was measured in day 2 samples and no significant difference was found between the depressed group and control subjects. In the depressed group cortisol concentration was elevated at 23:00 on day 1, and ACTH concentrations were elevated in post-dexamethasone samples. ACTH and cortisol concentrations were not directly correlated in individual patients. The elevated plasma cortisol associated with major depression is not solely mediated by changes in ACTH.

The prognosis of primary depressive illness. Its relationship to the dexamethasone suppression test

We followed up 30 recovered depressives for an average of 2 years. At 18 months, despite prophylactic medication, 30% had relapsed. Persistent DST suppression during the index illness was found to be a predictor of good prognosis.

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.

Dexamethasone suppression test (DST) in relation to depressive somatic and suicidal manifestations

An investigation of 51 depressed inpatients showed a significant positive correlation between non-suppression in dexamethasone suppression test (DST) and the extent of depressive somatic symptoms. The DST did not differentiate between depressive suicidal and non-suicidal patients.

Dexamethasone bioavailability: implications for DST research

The bioavailability of dexamethasone (DEX) has recently been demonstrated to be a critical factor in determining Dexamethasone Suppression Test (DST) status in psychiatric patients. This brief review focuses on several aspects of DEX bioavailability as they relate to the use of the DST in neuroendocrine research. Several methodologies, including radioimmunoassay, high-performance liquid chromatography, and gas chromatography-mass spectrometry are available for quantification of DEX in biological fluids, although few detailed comparisons between methods have been reported. Surprisingly, little systematic research on the metabolism of DEX has been reported, but it appears that hepatic rather than renal mechanisms are the major source of DEX elimination. The marked variability in serum DEX levels following oral administration in psychiatric patients is also observed in normal controls and patients with Cushing's syndrome. A variety of drugs can modify serum DEX levels and thereby after the effectiveness of DEX in suppressing serum cortisol levels. Simultaneous measurement of serum DEX and cortisol levels appears to be necessary for the appropriate evaluation of DST results. This procedure may help explain many of the inconsistencies in recent DST research.

DST nonsuppressor status: relationship to specific aspects of the depressive syndrome

Using a conservative definition of suppressor status in hospitalized depressives, we found a relationship between abnormal endocrine function and certain kinds of depressive symptoms, i.e., melancholic symptoms, delusions, and memory deficit. Normal suppressor status is related to an early age of onset, absence of delusions, absence of memory deficit, absence of melancholia symptoms, and a presence of a diagnosis of secondary depression or a family history of alcoholism in depressives. The data suggest the distinction between neurotic-reactive depression and endogenous depression. It is equally important to note that these specific symptoms and characteristics possibly are associated with suppressor status independently of each other.

The relationship of the dexamethasone suppression test (1 mg and 2 mg) to basal plasma cortisol levels in endogenous depression

The 1 mg and 2 mg dexamethasone suppression tests (DST) were evaluated in two groups of endogenously depressed patients (n = 39 and n = 30, respectively) who also had a 1300-1600 hr basal cortisol assessment. Non-suppressors (on both DSTs) had significantly higher basal plasma cortisol levels and thus were significantly associated with relative cortisol hypersecretion. However, there was only a partial overlap between DST response and basal plasma cortisol, with a large variation of cortisol levels among non-suppressors. The 2 mg DST appears to be more specific for cortisol hypersecretion than the 1 mg DST. If cortisol hypersecretion is to be identified, neither the 1 mg or 2 mg DST is an adequate assessment nor a substitute for a basal cortisol assessment.

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.

Discrimination of idiopathic pain syndromes from neurogenic pain syndromes and healthy volunteers by means of clinical rating, personality traits, monoamine metabolites in CSF, serum cortisol, platelet MAO and urinary melatonin

The aim of the present study was to investigate the discriminative power of a series of variables (including determination of depressive symptomatology by means of a visual analogue scale, determination of personality traits by means of the Karolinska Scales of Personality, determination of monoamine metabolites in CSF, platelet MAO activities, serum cortisol before and after dexamethasone suppression and urinary melatonin) in differentiating chronic pain patients from healthy subjects, and patients with idiopathic pain syndromes from patients with neurogenic pain syndromes. Separately each of the measures gave a significant but often low contribution to the discrimination, while a combination of several measures gave a complete discrimination both between healthy subjects and patients with chronic pain syndromes and between patients with idiopathic and neurogenic pain syndromes, respectively.

The effects of weight change on the dexamethasone suppression test in depressed and anorexic patients

Prior studies on weight change and hypothalamic-pituitary-adrenal (HPA) axis functioning are reviewed. Data on 58 depressed and eight anorexic patients is presented. No significant difference in the frequency of cortisol non-suppression in the dexamethasone suppression test (DST) was found between depressed patients with a history of weight loss and those without, nor between depressed patients who lost weight during their first week in hospital and those who did not. Mean weight loss of suppressors did not significantly differ from that of non-suppressors. Of 12 patients whose DST normalised during their stay in hospital, only four gained weight. Five anorexics who were non-suppressors were less than 70% of their ideal body weight (IBW), while three suppressor anorexics were greater than or equal to 70% IBW. These results indicate that mild to moderate weight change is not a significant influence on DST response in depression.

Abnormal dexamethasone suppression test in daily chronic headache sufferers

The dexamethasone suppression test (DST) was administered in 48 daily chronic headache (DCH) sufferers, 37 of whom also suffered from mild to severe depression. In 14 of 48 subjects (29.2%), cortisol values at 1600h were greater than 50 ng/ml, despite normal suppression at 0800h. The escapers showed basal cortisol values and (Depression scale) scores on the Minnesota Multiphasic Personality Inventory higher than suppressors. Thus, a group of DCH sufferers appeared to share a biochemical defect often seen in endogenous depression. The escape from dexamethasone suppression could be a psychobiological indicator of vulnerability to develop depressive disorder and/or chronic pain complaints.

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.

Clinical utility of the dexamethasone suppression test assessed by plasma and salivary cortisol determinations

Concentrations of cortisol in saliva and plasma were compared in matched samples during a standard 1 mg dexamethasone suppression test. The study involved 185 routine psychiatric admissions, all of whom were classified according to DSM-III criteria. In a group of 122 matched samples of saliva and plasma, there was a Pearson correlation coefficient of 0.867 and a Spearman rank correlation coefficient of 0.869. Medication with anticholinergic side effects had little effect on the correlation and was not associated with major difficulties in salivary sampling due to "dry mouth." In a group of 178 diagnoses where both saliva and plasma were obtained, results were almost identical. Although nonsuppression was found in all psychiatric conditions, there was a very significant association with major depressive episode with melancholia.

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.

Serial dexamethasone suppression tests in psychiatric illness: Part III. The influence of intervening variables

The effects of different intervening variables on dexamethasone suppression test (DST) results were evaluated in depressed, schizophrenic, and manic patients. There was a significant correlation between age and DST results in major depression. Some "isolated peaks" of DST nonsuppression were explained by low dexamethasone serum levels. In schizophrenic and manic patients, the dexamethasone concentrations increased to above the normal range during the study period. A significant negative correlation between dexamethasone concentrations and DST results was found in schizophrenia and mania, but not in depression. Dexamethasone levels were generally higher in men than in women. Weight loss and hospital admission affected the DST in individual cases, whereas length of episode and drug withdrawal did not. Thus, the intervening variables accounted for some of the abnormal DST results, but other factors such as severity of illness, nonspecific stress, or possibly depression itself emerged as the main causes of abnormal DST results.

Serial dexamethasone suppression tests in psychiatric illness: Part I. A study in schizophrenia and mania

Weekly dexamethasone suppression tests (DSTs) were performed in 15 patients with schizophrenia (n = 12) and mania (n = 3) until clinical response. At initial evaluation, 53.4% of the patients were nonsuppressors, and 93.3% showed nonsuppression at least once during the treatment period. There was a tendency for DST results to normalize coincident with clinical improvement, although single peaks of DST nonsuppression occurred in several patients irrespective of clinical course. The tests did not prove useful as predictors of recovery or relapse. DST nonsuppression occurred significantly more often in severely ill patients than in moderately ill patients or in patients after recovery, emphasizing the effects of nonspecific stress factors and/or severity of illness on the DST. The cutoff point, established on the basis of DST results in 67 healthy controls, was lower than in other studies, and nonsuppression among healthy controls was associated with low dexamethasone serum levels.

The plasma dexamethasone variable in depression: test-retest studies and early biophase kinetics

A dexamethasone suppression test (DST) was performed in 45 patients during depressive illness and after recovery. Thirty-one samples from patients in whom plasma cortisol was resistant to the suppressive action of dexamethasone contained significantly lower mean (+/- SD) concentrations of the test drug (0.63 +/- 0.39 ng/ml vs 1.10 +/- 0.53 ng/ml) during illness than after recovery and normalization of the DST. In a control group of 14 patients who exhibited adequate DST suppression during the depressive state and after recovery, the dexamethasone concentrations were unchanged (1.54 +/- 0.91 ng/ml vs. 1.30 +/- 0.92 ng/ml). To investigate further the influence of bioavailability or pharmacokinetics of the test drug on DST results, we conducted a catheter study during sleep in 11 endogenously depressed patients who received an oral 1.5 mg dose of dexamethasone at 11 p.m. The half-life of dexamethasone was markedly lower in five DST nonsuppressors (t1/2 = 160 +/- 33 minutes) than in six DST suppressors (t1/2 = 422 +/- 172 minutes). These preliminary results indicate that metabolism of dexamethasone should be controlled in studies evaluating the clinical utility of the DST.

Psychopathological correlates of plasma cortisol after dexamethasone suppression: a polydiagnostic approach

Seventy-seven consecutively admitted inpatients with depressive syndromes were examined with the Present State Examination and classified according to eight different operational diagnoses of endogenous depression. All patients received a 1.5 mg dexamethasone suppression test (DST). Sensitivity, specificity and the corrected predictive values of DST nonsuppression (50 or more ng/ml at 0800 hr, 1600 hr, or 2300 hr), adjusted to a 50% prevalence of endogenous and nonendogenous depression, varied considerably depending on the diagnostic definition used. The highest predictive value (89.9%) was found with the Taylor-Abrams criteria (sensitivity = 43.9%, specificity = 95.0%), and the lowest predictive value (53.3%) with DSM-III (sensitivity = 37.7%, specificity = 68.1%). Eliminating the patients with dexamethasone levels of less than 2000 pg/ml improved the diagnostic specificity of the DST for most of the eight definitions of endogenous depression. This further indicates that plasma dexamethasone levels should be analyzed in studies designed to explore the diagnostic utility of the DST. A significant, chance-corrected association between DST nonsuppression and the diagnosis of endogenous depression was found with clinical diagnosis (according to the International Classification of Diseases), and for four out of eight operational diagnoses (Newcastle Scale I, Newcastle Scale II, Taylor-Abrams Criteria, and Vienna Research Criteria). For the other diagnoses (Research Diagnostic Criteria, DSM-III, Michigan Discriminant Index, and Hamilton Endogenomorphy Index), no significant association was found. The RDC criterion "early or intermittent awakening" was the only one out of 28 diagnostic criteria tested which was significantly associated with DST nonsuppression.

Effect of experimental and pathological weight loss upon the hypothalamo-pituitary-adrenal axis

Five healthy female subjects participated in a starvation experiment. After an initial baseline phase (A) they lost about 8 kg in a 3-week phase of complete food abstinence (B); thereafter they recovered to their original body weight (C) and kept this weight stable over more than 4 weeks (D). While all dexamethasone suppression tests (DST's) during the initial baseline were normal, half of the DST's (7/14) in the fasting phase showed insufficient suppression. In the following weight gain phase, all DST's were sufficiently suppressed. Twenty-four hour plasma cortisol patterns during fasting (B) showed a significant increase, as well as increased cortisol half-life, increased time in secretory activity, and increased number of secretory episodes. Administration of the alpha 2-adrenergic receptor agonist clonidine during fasting did not induce a further decrease in plasma cortisol level, whereas it did during baseline. The results demonstrate that weight loss, reduced caloric intake, and catabolic state have a very powerful influence on the hypothalamo-pituitary-adrenal (HPA) axis and other endocrine systems. The results shed new light on endocrine dysfunctions in mental disorders associated with reduced caloric intake, such as anorexia nervosa and depression, and question the specificity of certain endocrine dysfunctions for depression.

The dexamethasone suppression test in depressive and schizophrenic patients under controlled treatment conditions

Endogenous depressive and schizophrenic patients demonstrated the same frequency of pathological DST results after admission. After 3 weeks of psychopharmacological treatment the percentage of abnormal DST results was significantly reduced in both groups, although the treatment conditions were different. A correlation between the DST non-suppression and intensity of depression was observed only in the depressive group, not in the schizophrenic group. Normalization of DST results in depressive patients was mostly associated with an improvement of depressive scores. Other course patterns of DST results did not seem to be combined with psychopathological changes. From this data it has to be concluded that DST non-suppression is in some part related to depressive symptoms, but is not characteristic or specific for endogenous depression or for depressivity.

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

Recent studies from different research groups have raised fundamental questions about the postulated specificity of the dexamethasone suppression test (DST) for endogenous depression. Findings in 116 psychiatric inpatients and 24 semi-starved healthy volunteers underline the importance of weight loss as a factor affecting DST results. A study of 160 DSTs in 93 psychiatric inpatients further revealed a significant negative correlation of plasma cortisol and plasma dexamethasone levels 10 hours after oral administration of 1 mg of dexamethasone. These results suggest a decisive effect of the pharmacokinetics of dexamethasone, at least on the 1-mg DST.

DST in healthy volunteers and after sleep deprivation

The dexamethasone suppression test (DST) was performed in 46 healthy volunteers and repeated in nine of them following total sleep deprivation (TSD). While only 2 postdexamethasone cortisol values were insufficiently suppressed (greater than 5 micrograms %) in control DSTs, 5 postdexamethasone cortisol values were above 5 micrograms % following TSD. The mean postdexamethasone value was increased from 1.55 +/- 1.06 to 4.47 +/- 5.86 micrograms % following TSD at 8.00 h. The authors conclude that sleep deprivation as a therapeutic approach and prolonged sleeplessness may bias DST results.

Dexamethasone suppression test as a simple measure of stress?

Non-suppression of cortisol by dexamethasone has been described as a biological marker of a diagnostic subgroup of depressed patients. This paper presents the hypothesis that the degree of non-suppression is a variable that reflects the quantity of stress or distress experienced by the patient rather than relating to a specific diagnosis. Such a quantitative measure of stress would be valuable for research in general medicine as well as in psychiatry. Testing of this postulate should apply a more precise interpretation of endocrine principles than has been applied to the dexamethasone suppression test to date.