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

Dexamethasone suppression test in chronic schizophrenia

Dexamethasone suppresson test (DST) was administered to 26 chronic schizophrenic inpatients who were on stable doses of neuroleptics for over 3 months. Clinical assessments were made on the Brief Psychiatric Rating Scale (BPRS), the Manchester Scale (KGV) and the Scale for the Assessment of Negative Symptoms (SANS). Patients’ neuroleptic treatment was then stopped for 4 weeks and the clinical assessements and the DST repeated. Thirty two percent of the patients showed DST non-suppression which was mostly stable over the 4-week period of the study and was unaffected by the neuroleptic treatment. Contrary to some reports in the literature, the clinical rating scores (including those for depression and negative symptoms), in our patients, showed no relationship with the DST status. We suggest that the DST abnormality in chronic schizophrenies may result from two quite different mechanisms: one due to stress assoeiated with transient psychopathology such as agitation, anxiety, depression or psychotic perturbation which is transient, the other resulting from structural abnormalities in the brain and which remains stable over time.

Exploration de l’influence noradrénergique (par le dosage du MHPG urinaire) sur le test de freinage à la dexaméthasone chez les déprimés

Une hyperactivité de l’axe hypothalamo-hypophyso-cortico-surrénalien est souvent objectivée dans les dépressions majeures ou endogènes, particulièrement par le test de freinage à la dexaméthasone (DST).

Certaines hypothèses évoquent un dysfonctionnement noradrénergique pour expliquer cette anomalie.

Afin de rechercher les liens entre l’axe HPA et une anomalie du métabolisme de la noradrénaline (NA) cérébrale, 47 déprimés majeurs ont été étudiés.

Pour chaque déprimé étaient mesurés l’excrétion urinaire du MHPG de 24 heures et un test de freinage à la dexaméthasone était effectué.

Aucune corrélation n’est retrouvée entre l’âge et la sévérité de la dépression d’une part et d’autre part, l’excrétion du MHPG et les chiffres de cortisolémie pré et post dexaméthasone. Par contre, il existe une corrélation positive entre l’âge et l’excrétion du MHPG et entre l’âge et la cortisolémie post dexaméthasone, entre la durée du sevrage thérapeutique et la cortisolémie pré dexaméthasone et surtout, entre la cortisolémie pré DST et post DST.

Aucune corrélation ne peut âtre retrouvée entre l’excrétion du MHPG et la cortisolémie maximale post dexaméthasone.

Il n’y a pas de différence d’excrétion urinaire du MHPG entre les suppresseurs et les non suppresseurs qui sont au nombre de 19 (40 %).

Lorsque les déprimés sont séparés en hauts excréteurs et bas excréteurs de MHPG, il existe une tendance significative des déprimés hauts excréteurs à présenter un pourcentage supérieur de non suppresseurs.

L’étude ne confirme pas l’hypothèse hyponoradrénergique de l’échappement à la dexaméthasone. Elle tend plutôt à démontrer une association entre une hyperactivité de l’axe HPA et une excrétion urinaire élevée de MHPG.

De nombreux facteurs peuvent peut-âtre expliquer les difficultés à mettre en évidence les liens entre l’échappement au freinage par la dexaméthasone et une anomalie du métabolisme de NA cérébrale lorsque des mesures biologiques périphériques sont utilisées.

Atypical depression and non-atypical depression: Is HPA axis function a biomarker? A systematic review

BACKGROUND

The link between the abnormalities of the Hypothalamic-pituitary-adrenal (HPA) axis and depression has been one of the most consistently reported findings in psychiatry. At the same time, multiple studies have demonstrated a stronger association between the increased activation of HPA-axis and melancholic, or endogenous depression subtype. This association has not been confirmed for the atypical subtype, and some researchers have suggested that as an antinomic depressive subtype, it may be associated with the opposite type, i.e. hypo-function, of the HPA-axis, similarly to PTSD. The purpose of this systematic review is to summarise existing studies addressing the abnormalities of the HPA-axis in melancholic and/or atypical depression.

METHOD

We conducted a systematic review in the literature by searching MEDLINE, PsycINFO, OvidSP and Embase databases until June 2017. The following search items were used: "hypothalamic-pituitary-adrenal" OR "HPA" OR "cortisol" OR "corticotropin releasing hormone" OR "corticotropin releasing factor" OR "glucocorticoid*" OR "adrenocorticotropic hormone" OR "ACTH" AND "atypical depression" OR "non-atypical depression" OR "melancholic depression" OR "non-melancholic depression" OR "endogenous depression" OR "endogenomorphic depression" OR "non-endogenous depression". Search limits were set to include papers in English or German language published in peer-reviewed journals at any period. All studies were scrutinized to determine the main methodological characteristics, and particularly possible sources of bias influencing the results reported.

RESULTS

We selected 48 relevant studies. Detailed analysis of the methodologies used in the studies revealed significant variability especially regarding the samples' definition comparing the HPA axis activity of melancholic patients to atypical depression, including healthy controls. The results were subdivided into 4 sections: (1) 27 studies which compared melancholic OR endogenous depression vs. non-melancholic or non-endogenous depression or controls; (2) 9 studies which compared atypical depression or atypical traits vs. non-atypical depression or controls; (3) 7 studies which compared melancholic or endogenous and atypical depression subtypes and (4) 5 studies which used a longitudinal design, comparing the measures of HPA-axis across two or more time points. While the majority of studies did confirm the association between melancholic depression and increased post-challenge cortisol levels, the association with increases in basal cortisol and basal ACTH were less consistent. Some studies, particularly those focusing on reversed vegetative symptoms, demonstrated a decrease in the activity of the HPA axis in atypical depression compared to controls, but the majority did not distinguish it from healthy controls.

CONCLUSIONS

In conclusion, our findings indicate that there is a difference in the activity of the HPA-axis between melancholic and atypical depressive subtypes. However, these are more likely explained by hypercortisolism in melancholia; and most often normal than decreased function in atypical depression. Further research should seek to distinguish a particular subtype of depression linked to HPA-axis abnormalities, based on symptom profile, with a focus on vegetative symptoms, neuroendocrine probes, and the history of adverse childhood events. New insights into the dichotomy addressed in this review might be obtained from genetic and epigenetic studies of HPA-axis related genes in both subtypes, with an emphasis on the presence of vegetative symptoms.

Dexamethasone suppression test in mentally handicapped subjects

Objective:This study investigated the frequency of abnormal Dexamethasone Suppression Test (DST) in a randomly selected group of mentally handicapped subjects.Method:Forty three subjects living in the community were selected and assessed on a variety of clinical rating scales including Hamilton Rating Scale for Depression (HDS) and Wessex Case Register Form (WCRF). DST was conducted on all the patients and the findings correlated with demographic and clinical variables. Groups defined by DST status were also compared using t-test. In subjects who showed an abnormal response, clinical assessments and DST was repeated after 3 months.Results:Only 7 of 43 subjects showed an abnormal response which did not correlate with either the severity of affective symptoms or the presence or absence of behavioural difficulties. Six of the 7 DST positive subjects were either severely or profoundly impaired on DSM-III criteria indicating that the underlying brain pathology may be pathogenetically important. This was supported by the observation that abnormal DST response was enduring at follow up.Conclusions:The findings suggest that DST may be of little value as a diagnostic tool in the mentally handicapped.

A randomised controlled study of risperidone and olanzapine for schizophrenic patients with neuroleptic-induced acute dystonia or parkinsonism

The objective of this study was to compare the effects of risperidone and olanzapine in schizophrenic patients with intolerant extrapyramidal side effects (EPS) on first generation antipsychotics. We conducted an 8-week, rater-blinded, flexible dose study. Seventy patients with schizophrenia, who met the DSM-IV research criteria of having neuroleptic-induced acute dystonia or parkinsonism, were randomly assigned to risperidone or olanzapine group. The primary outcome was a comparison of the incidence of concomitant anticholinergic drugs usage between the groups to manage their acute dystonia and parkinsonism. The average doses of risperidone and olanzapine from baseline to study end point were 1.8-3.5 mg/day and 7.7-11.7 mg/day, respectively. There were no significant differences in demographic data, severity of EPS or psychotic symptoms between the groups at baseline assessment. Patients taking risperidone had significantly higher incidence of using anticholinergic drugs to manage acute dystonia or parkinsonism overall during the study (OR = 5.17, 95%CI = 1.49-17.88, P = 0.013). There was no significant between-group difference in the changing of rating scales of EPS and psychotic symptoms. The results of our study favour olanzapine as a better choice in schizophrenic patients with intolerant EPS. Double-blinded, fixed dose and different ethnical study for EPS-intolerant schizophrenic patients is needed to confirm the results of our study.

A systematic review of hypothalamic-pituitary-adrenal axis function in schizophrenia: implications for mortality

There is convincing evidence that environmental stress plays a significant role in modifying both mental and physical health. The biological mechanisms linking stress to ill health are not fully understood, but significant evidence points to a central role of the stress axes; the hypothalamic- pituitary-adrenal (HPA) axis and the sympathetic nervous system. Together these two systems link the brain and the body and are crucial in maintaining homeostasis as well as improving an organism's survival chances in the face of environmental challenge. There is evidence of altered HPA axis function in people with a range of mental disorders, and this may in part explain the poor physical health of people with psychotic, mood and anxiety disorders. This paper systematically reviews HPA axis function in people with schizophrenia and relates this to the pattern of physical health seen in this disease. In summary, the evidence suggests people with schizophrenia can experience both hyper- and hypo-function of the HPA axis. It is likely that this contributes to the pattern of poor physical health and premature mortality suffered by people with schizophrenia, in particular the high rates of cardiovascular and metabolic disturbance.

The dexamethasone suppression test and CSF-5-HIAA in relation to suicidality and depression in suicide attempters

This study tested suicidality in relation to cerebrospinal fluid (CSF) 5-hydroxyindoleacetic acid (5-HIAA) and the dexamethasone suppression test. Patients with nonsuppression of cortisol had the highest scores of the Suicide Assessment Scale (SUAS) and the Montgomery Asberg Depression Rating Scale (MADRS), respectively (P < 0.05; P < 0.01). The results persisted when analysed for covariance with CSF-5-HIAA. We have previously noted an elevated suicide risk in suicide attempters with high SUAS-scores, why a large part of nonsuppressors may be at high risk for future suicide.

HPA hyperactivity with increased plasma cortisol affects dexamethasone metabolism and DST outcome

Data suggests that dexamethasone bioavailability or pharmacokinetic factors contribute importantly to the outcome of the dexamethasone suppression test, and a relationship between plasma cortisol and plasma dexamethasone levels has been shown. To evaluate these data further, we studied plasma dexamethasone pharmacokinetics in 24 patients with major depression (15 suppressors and nine nonsuppressors) who received a 1 mg IV dexamethasone bolus at 09:00 h with blood samples collected at intervals over the next 14 h. We found that nonsuppressors had significantly shorter plasma dexamethasone half-life (P = 0.003) as well as significantly lower dexamethasone levels 10 h (P = 0.02) following IV dexamethasone administration. Moreover, upon clinical improvement of patients, the shortened dexamethasone half-life and lower dexamethasone levels disappeared in the five patients who switched from nonsuppression to suppression and were restudied by IV bolus. These 10-h post IV plasma dexamethasone level findings paralleled the results of the 1 mg overnight oral DST performed in these depressed patients (N = 22) where we found significantly lower 10 h plasma dexamethasone levels in nonsuppressors on admission compared to suppressors (P = 0.002) and again at discharge (P = 0.007). Interestingly, in the few patients who switched from suppression to nonsuppression over the course of hospitalization, 10-h post dose plasma dexamethasone levels simultaneously dropped. No difference in dexamethasone half-life was observed in the patients studied by oral and IV dexamethasone administration. These findings support the concept that metabolism of dexamethasone is significantly related to the activity of the HPA axis (particularly by plasma cortisol levels), and that dexamethasone pharmacokinetics can be modified by state-dependent phenomena.

Hypercortisolemia decreases dexamethasone half-life in rabbit

The pharmacokinetics of dexamethasone have been found to be related to endogenous hypothalamic-pituitary-adrenal (HPA) axis activity. Lower plasma dexamethasone levels in psychiatric patients (especially depressed) who are dexamethasone suppression test (DST) nonsuppressors have previously been reported. Since DST nonsuppression is one measure of HPA axis hyperactivity and is usually associated with relatively increased plasma cortisol levels and lower post dose plasma dexamethasone levels, we hypothesized that hypercortisolemia can induce a more rapid disappearance of dexamethasone from plasma. We therefore studied the kinetics of dexamethasone in rabbits before and after a period of sustained hypercortisolemia produced by administration of IM hydrocortisone acetate, a slowly absorbed salt of cortisol. Mean dexamethasone half-life decreased significantly from baseline of 1.92 h on day zero in seven rabbits to 1.17 h on experimental day 17 of induced hypercortisolemia (P < 0.001), while there was no significant change in saline treated controls (n = 3). Dexamethasone half-life had returned to the baseline levels when retested 88 days later on experimental day 105. The results indicate that pronounced hypercortisolemia decreases dexamethasone half-life in rabbits, and support the concept that increased circulating cortisol levels induce hepatic enzymes that metabolize dexamethasone. Thus, the lower postdexamethasone plasma dexamethasone levels and decreased dexamethasone half-life in DST nonsuppressors may in part reflect the effect of prior or coincident hypercortisolemia.

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.

Dexamethasone metabolism in dexamethasone suppression test suppressors and nonsuppressors

BACKGROUND

Variable dexamethasone kinetics is a possible confound in the dexamethasone suppression test. Modifications to include dexamethasone plasma levels and specific dexamethasone "windows" have been proposed. Our study aims to validate our proposed dexamethasone windows in an independent sample of 121 subjects.

METHODS

We performed dexamethasone suppression tests in 162 subjects with mixed psychiatric diagnoses. Dexamethasone levels and beta-phase half-life of dexamethasone were computed for suppressors and nonsuppressors.

RESULTS

Dexamethasone levels were lower in nonsuppressors than in suppressors. Dexamethasone levels correlated inversely with cortisol levels in the total sample, but were nonsignificant or weakly associated in those samples restricted to the windows. The beta-phase half-life of dexamethasone was shorter in nonsuppressors. The dexamethasone windows were validated at 3:00 PM and 10:00 PM. We propose 4.0 ng/mL as a revised upper limit of the 8:00 AM dexamethasone window.

CONCLUSIONS

The plasma dexamethasone level is confirmed as a confound in the dexamethasone suppression test through more rapid dexamethasone clearance in nonsuppressors. Application of dexamethasone windows will reduce this source of test variance.

Patterns of DST positivity in remitted affective disorders

BACKGROUND

While the Dexamethasone Suppression Test (DST) has been extensively used in cross-sectional observations of patients with major affective disorders, studies have tended to ignore the longitudinal application of the DST in patients stabilized on long-term prophylactic medication.

METHODS

Monthly DST's were performed on 19 patients, 16 with bipolar disorder and 3 with recurrent major depression. All cases had an excellent response to lithium treatment, and family history positive for bipolar disorder. The average duration of observation was 4 years.

RESULTS

All patients remained clinically stable throughout the period of observation. Eleven patients showed intermittent DST positivity ranging from 10% to 60% of tests, and 2 patients exhibited no positivity. Six patients had fewer than 10% positive DST's. Females showed significantly higher positivity than males. The frequency of positivity did not correlate with current age, age of illness onset, duration of illness, duration of lithium treatment, or season. The risk of primary affective disorders in first-degree relatives was also unrelated to the frequency of positivity.

CONCLUSIONS

While the highly selected and small sample population limits generalizability, our observations suggest that clinically sufficient lithium prophylaxis does not automatically prevent intermittent HPA dysregulation. We hope that a better understanding of this phenomenon will offer new approaches to the long-term management of mood disorders.

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.

Emotion and immunity

Earlier studies have suggested that depression is associated with decreased immune function, but a recent literature review has revealed that a majority of studies reached inconsistent or conflicting conclusions. On the other hand, studies on immune function in anxiety disorders are sparse, and their findings are also inconsistent. Despite a few contradictory results, a clinical level of anxiety seems to reduce immune function, whereas a subclinical level of anxiety seems to enhance immunity. The latter may be a transient phenomenon occurring prior to the downregulation of immune function, reflecting the body's defense to a stressor. Thus, research needs to be conducted to elucidate the relationship between those hormones related to hypothalamic-pituitary-adrenal axis and a variety of immune measures at the subclinical level of anxiety. In addition, to confirm the interaction between emotion and immune function, the effectiveness of treatment with medication and psychotherapy on immunity should be investigated.

Plasma dexamethasone concentration and cortisol response during manic episodes

BACKGROUND

Despite the widespread study of the dexamethasone suppression test (DST) in patients diagnosed with major depression, it has been less well studied during manic and mixed states of bipolar disorder.

METHODS

Cortisol response to the administration of 1 mg of dexamethasone was studied in 44 patients diagnosed bipolar disorder, manic (n = 37) or mixed (n = 7). Dexamethasone levels and cortisol responses were compared between these groups. Four patients initially meeting criteria for bipolar disorder, mixed, and 7 patients initially meeting criteria for bipolar disorder, manic, all of whom were characterized as DST nonsuppressors, were retested after remission.

RESULTS

Dexamethasone levels were lower and cortisol levels higher in those patients diagnosed bipolar disorder, mixed. An inverse correlation was found between log-transformed dexamethasone levels and log-transformed cortisol levels at 3 PM (r = -.619, p < or = .001) and 10 PM (r = -.501, p < or = .001). In those subjects retested after remission, dexamethasone levels were higher and cortisol levels lower than during the manic and mixed states.

CONCLUSIONS

Disturbances in the hypothalamic-pituitary-adrenal axis are observed frequently during mixed states of bipolar disorder, but are also not uncommon in purely manic episodes. These changes appear to be state dependent and revert with treatment.

48-hour rapid cycling: results of psychopathometric, polysomnographic, PET imaging and neuro-endocrine longitudinal investigations in a single case

We report a 64-year-old patient suffering from rapid cycling bipolar disorder who was studied by means of polysomnography, neuroendocrine tests and PET (positron emission tomography) imaging. In a manner only partly compatible with the cholinergic-aminergic imbalance model of mania and depression, a linkage of REM sleep disinhibition and depressive mood was observed, but no decisive REM sleep delay was seen on manic days. Growth hormone secretion after clonidine stimulation was blunted on depressive and hypomanic days. A series of total sleep deprivations led to a positive effect on psychopathology for about two weeks. Carbamazepine treatment normalized REM sleep variables, damped the amplitude of mood cycling of the patient, increased TSH and decreased FT4.

The hypothalamic-pituitary-thyroid axis in depressive patients and healthy subjects in relation to the hypothalamic-pituitary-adrenal axis

Serum levels of thyroid stimulating hormone (TSH), triiodothyronine (T3), free T3 index (fT3i), thyroxine (T4), and free T4 index (fT4i) were measured before and after administration of 1 mg of dexamethasone in 54 depressive patients and 54 matched healthy subjects. A followup study at a mean of 2 years was performed in 28 patients in remission. Basal TSH levels were lower and fT4i levels were higher in major depressive patients compared with healthy subjects. After dexamethasone administration, there was no significant change in any of the hormones in a subgroup of 46 major depressive patients in contrast to matched healthy subjects, who showed a significant decrease in the levels of TSH, T3, and fT3i. The magnitude of the TSH response to dexamethasone in the major depressive patients was related to the level of nocturnal urinary cortisol excretion and pathological dexamethasone suppression test results. The level of TSH in depressive patients during remission did not return to levels similar to those found in the healthy subjects.

The role of stress in interpreting the dexamethasone suppression test

Stress has been implicated as a major confounding factor in the interpretation of Dexamethasone Suppression Test (DST) results. This study was designed to examine the effects of stress on DST results. Fifty patients with high levels of acute, chronic, and environmental stress participated in the study. Each patient was given a comprehensive psychiatric and psychological assessment, a routine administration of dexamethasone, and blood tests of cortisol values. The results indicate that the three measures of stress do not appear to affect levels of cortisol suppression, however, all three measures of stress predicted depression. As expected, DST cortisol levels were related to depression. Results are discussed in terms of their implications for understanding the associations among stress, depression and DST results.

The dexamethasone suppression test in children and adolescents: a review and a controlled study

Dexamethasone Suppression Test (DST) studies conducted in children and adolescents are reviewed, together with factors hypothesized to explain discrepancies in rates of DST nonsuppression across studies. These factors are then examined in a controlled study of 27 adolescents with major depressive disorder (MDD) and 34 normal controls (NC). Subjects were given 1 mg of dexamethasone at 11:00 PM, and the following day serum samples for cortisol were collected each hr from 8 AM to 11 PM through an indwelling catheter. There were no significant differences found between the MDD and NC subjects on any postdexamethasone cortisol measure. Further, cortisol suppressors and nonsuppressors were not distinguished by any of the hypothesized factors identified from the review, including inpatient status, presence of suicidality, endogenous features, psychotic symptoms, or prior history of MDD. Questions about the appropriateness of the 1 mg dose of dexamethasone (currently the standard dose used with adolescents) are raised, together with a discussion of the effects of stress on DST findings.

Modeling the pharmacokinetics and pharmacodynamics of dexamethasone in depressed patients

Changes in time course effected by cortisol suppression and the relationship of these changes to the plasma dexamethasone concentration of suppressor and non-suppressor patients are described in this report on a combined pharmacokinetic-pharmacodynamic model. Thirteen depressed patients (8 suppressors and 5 non-suppressors) received an intravenous dose (1.5 mg) of dexamethasone. The drug-induced effect changes are found to lag behind, in time, the plasma drug level changes. To accurately relate the temporal relationship of effect changes to plasma dexamethasone levels, a pharmacodynamic model (sigmoid-Emax) was combined with a pharmacokinetic model that incorporated an effect compartment. The magnitude of the time-lag was quantified by the half-time of equilibration between concentrations in the hypothetical effect compartment and the plasma dexamethasone levels (t1/2keo). The t1/2keo of the nonsuppressing group was about 50% of that of the suppressing group, indicating that for a given plasma level the onset and termination of effect for the nonsuppressing group is about two times more rapid than for the suppressing group. Moreover, the model can estimate the effect-site concentration that causes one-half of the maximal predicted effect (EC50), a measure of an individual's sensitivity to dexamethasone. The receptor sensitivity (as determined from the EC50 ratio) of the suppressing group was about twice that of the nonsuppressing group.

HPA-related CSF neuropeptides in suicide attempters

Corticotropin-releasing hormone (CRH), somatostatin (SOM), delta-sleep-inducing peptide (DSIP), neuropeptide Y (NPY), beta-endorphin (beta-END), and vasopressin (AVP), which are regarded as being involved in the HPA-regulation were investigated in lumbar CSF of 44 suicide attempters. The patients were diagnosed according to the DSM-III-R, and rated with the MADRS. The neuropeptides were compared with the serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA) in CSF and with post-dexamethasone plasma cortisol. We found strong correlations between CRH and the peptides SOM and beta-END. The latter also correlated positively with SOM. There were no differences between men and women. Patients with major depressive disorders had significantly lower SOM, CRH, and DSIP than other patients. Both SOM and beta-END correlated negatively with post dexamethasone plasma cortisol in all patients. We found no significant relationships between neuropeptides and CSF 5-HIAA. Patients who had made previous suicide attempts had significantly lower CRH than those who had not. No other significant associations between neuropeptides and suicidal subgroups of patients appeared, and there was no indication of specific neuropeptide patterns in patients who later completed suicide. Intercorrelations of some neuropeptides and low SOM and DSIP in major depressed patients are findings in line with those by others.

Dexamethasone suppression test in children with major depressive disorder

The authors report a study of 24-hour serial cortisol determinations, measured during baseline and after the administration of 0.25 and 0.5 mg of dexamethasone in a sample of predominantly outpatient children with major depressive disorder, nonaffective psychiatric controls, and normal controls. In this sample, 24-hour baseline cortisol and the dexamethasone suppression test (DST) do not discriminate between the three groups. In addition, the authors measured 24-hour serum dexamethasone levels. There were no significant between group differences in serum dexamethasone. These results raise questions as to the utility of this test in the diagnosis of affective disorders in children. Possible reasons for the discrepancies in the dexamethasone suppression test results between in- and outpatient studies are discussed.

Long-latency auditory event-related potentials in schizophrenia and in bipolar and unipolar affective disorder

Long-latency auditory event-related potentials were examined in 96 subjects with schizophrenia, 99 with bipolar affective disorder and 48 with major depressive (unipolar) disorder, and compared with 32 in-patient and 213 normal controls. The latency of the P3 component was significantly greater in the schizophrenic and bipolar subjects compared to other groups. The difference was stable with respect to clinical state at the time of testing and was not due to age differences or the effect of psychotropic medications. The results support the clinical distinction between bipolar and unipolar affective disorders, but also show that P3 change is not specific to schizophrenia and found in bipolar but not unipolar affective disorder.

Psychoendocrinological aspects of affective disorders

Psychoendocrinological studies have opened a new approach to understanding affective disorders. In this study, the links of affective illnesses to changes in endocrine secretions--particularly adrenal, gonadal, growth, pineal, thyroidal, and prolactin--were reviewed with the object of adding to the number of depressed whose symptoms can be relieved.

24-hour cortisol measures in adolescents with major depression: a controlled study

Plasma cortisol levels were determined every 20 min for 24 hr in depressed adolescents (n = 27) meeting research diagnostic criteria (RDC) for major depressive disorder (MDD) and normal controls (n = 32). All subjects were between 12 and 18 years of age, at least Tanner Stage III of sexual development, medically healthy, and medication free at the time of the studies. The results showed that cortisol secretory patterns were very similar between the two groups with the exception that the depressed adolescents showed significantly elevated cortisol levels around sleep onset (a period when cortisol is usually suppressed). Subgroup analyses showed that most of these differences were contributed by the suicidal/inpatient depressed adolescents. The cause of the elevated cortisol during the normally quiescent period warrants further investigation and may be related to other biological disturbances around sleep onset (difficulty initiating sleep, reduced rapid eye movement (REM) latency, and alterations in sleep-stimulated growth hormone secretion).

Dexamethasone suppression test in schizophrenia: relationship to symptomatology, ventricular enlargement, and outcome

To relieve confusion about the clinical correlates and prognostic implications of the dexamethasone suppression test (DST) in schizophrenia, we conducted a DST in 44 schizophrenic inpatients at drug-free baseline and approximately 4 weeks after neuroleptic treatment. Patients were rated on positive, negative, and depressive symptoms at both times. A head computed tomography (CT) scan was performed and measures of ventricle-brain ratio (VBR) obtained. Clinical improvement was monitored at four weeks, and longer-term outcome assessed at 1 year. Seventeen of the 44 patients were DST nonsuppressors at baseline, and five of these remained nonsuppressors at 4 weeks posttreatment. Postdexamethasone plasma cortisol levels were correlated with negative symptoms at baseline (r = 0.45; p less than 0.01), but not after 4 weeks of neuroleptic treatment. Postdexamethasone plasma cortisols were not related to global severity, positive, or depressive symptoms at either timepoint or to VBR. Persistent nonsuppression was associated with poor outcome, but baseline postdexamethasone cortisol levels were unrelated to outcome at 4 weeks and 1 year. The literature on DST in schizophrenia is reviewed and attempts are made to reconcile discrepant findings and to discuss pathophysiological implications.

Effect of high plasma dexamethasone levels on DST sensitivity: dose-response study in depressed patients and controls

The aim of this study was to examine cortisol dynamics over a range of plasma dexamethasone (DEX) levels using a two-dose dexamethasone suppression test (DST). Two doses of DEX (0.5 and 1.5 mg) were administered in a randomized crossover design to 29 inpatients with major depression and 26 controls to identify the upper range of plasma DEX levels that would allow reliable interpretation of DST results. It was hypothesized that due to inappropriately high plasma DEX levels following 1.5 mg, several depressed patients would switch from suppressors after the 1.5 mg dose to nonsuppressors after 0.5 mg. In contrast, the nondepressed controls with high DEX levels following 1.5 mg would remain suppressors after the lower dose. Fourteen patients were identified as having high 4 p.m. DEX levels (greater than 4 nmol/l) after the 1.5 mg DST. Cortisol was suppressed in all of the subjects with high DEX levels. After 0.5 mg, five of the eight depressed patients with high DEX levels switched to nonsuppressors. In contrast, all six controls with high DEX levels remained suppressors. These results indicate that patients with high DEX levels after a 1 mg DST should be retested with a lower dose. This strategy enhances the sensitivity of the DST without loss of specificity.

A longitudinal evaluation of dexamethasone and cortisol plasma concentrations in the dexamethasone suppression test before and during treatment with antidepressant drugs

Thirty depressed in- and outpatients received serial dexamethasone suppression tests (DSTs). Plasma dexamethasone and cortisol concentrations were drawn at 1600 on the day following a 1-mg oral dose of dexamethasone. The first DST was performed after patients were drug-free for a period of 1 week; the second, third, and fourth DSTs while patients received antidepressant medication. Dexamethasone and cortisol concentrations drawn in the drug-free period correlated significantly. The cortisol to dexamethasone ratio changed significantly with time in DST nonsuppressors, suggesting that nonsuppression is associated with an altered pharmacodynamic response of the hypothalamopituitary-adrenal axis to dexamethasone during depression. When dexamethasone concentrations from the drug-free period were compared with those drawn during antidepressant treatment, no significant differences were noted.

The dexamethasone suppression test in anorexia nervosa. The influence of weight, depression, adrenocorticotrophic hormone and dexamethasone

When 20 female anorexic in-patients were investigated with weekly DSTs, 10 had an abnormal result at initial testing. There was no identifiable relationship between severity of weight loss and DST status; % ideal body weight was no different between suppressors and non-suppressors. There was no consistent relationship between normalisation of the DST response and weight gain. Depressive symptoms were common, with half the patients scoring 20 or more on the HRSD. Plasma ACTH concentrations before and after the DST were normal. There was a significant negative correlation between plasma dexamethasone concentrations and pre- and post-dexamethasone plasma cortisol concentrations.

The effect of dexamethasone dosage upon plasma cortisol and dexamethasone during the DST

To investigate the effect of dexamethasone dosage upon the outcome of the dexamethasone suppression test (DST) and the role of concurrent plasma dexamethasone concentrations, four different dexamethasone dosages were administered to 119 hospitalized depressed patients (0.5 mg: n = 12; 1.0 mg: n = 30; 1.5 mg: n = 42; 2.0 mg: n = 35). Independent of the dosage, dexamethasone plasma concentrations at 4.00 p.m. were lower in DST non-suppressors than in suppressors, although differences were statistically significant only for the 1.5-mg and 2.0-mg dosages. Our findings confirm recent reports that the actual plasma concentration of dexamethasone at 4.00 p.m. does not determine DST outcome.

Depression dexamethasone nonsuppression and negative symptoms in schizophrenia

This study compared three measures of depression in schizophrenia and their correlation with the Dexamethasone Suppression Test (DST). The degree of overlap of these three measures with negative symptoms was also examined. The Hamilton Depression Rating Scale (HDRS), the depressive syndrome score of the Present State Examination (PSE), and the Scale for the Assessment of Negative Symptoms (SANS) were administered to 50 acutely ill, hospitalized schizophrenics. Patients were diagnosed using DSM-III criteria for schizophrenia. DSM-III criteria were also used to assess the presence of a major depressive episode. Results were that DST nonsuppression was significantly associated with the presence of a major depressive episode, but not with depressive rating scale scores or with negative symptoms. It is concluded that the DST may be of value in differentiating a depressive syndrome from a negative symptom syndrome in schizophrenia.

The incidence of abnormal dexamethasone suppression in schizophrenia: a review and a meta-analytic comparison with the incidence in normal controls

Studies on dexamethasone suppression test (DST) and schizophrenia are reviewed and the incidence of nonsuppression in the group of studies on schizophrenic patients is compared to that in the group of studies on normal controls from a previous review article. The incidence of nonsuppression in schizophrenic patients (26.4%) is significantly higher than that in normal controls (5.0%). There may be a subgroup of schizophrenic patients with an increase in cholinergic functioning. The variance of the nonsuppression rates of DST were also significantly higher in patients with schizophrenia compared to normal controls. This may be due to a heterogeneity of mechanisms that is responsible for the DST non-suppression due to the heterogeneous nature of the diagnosis of schizophrenia. The possible mechanisms of abnormal and varied DST results in schizophrenia are discussed.

Interactions of anxiolytic and antidepressant drugs with hormones of the hypothalamic-pituitary-adrenal axis

Changes in hormones of the hypothalamic-pituitary-adrenal (HPA) axis in patients suffering from anxiety and depressive disorders are reviewed, and the changes that occur when animals are exposed to test situations used preclinically to model anxiety or depression. The effects of exogenous administration of HPA hormones both clinically and in animal tests is discussed and the effects of clinically used anxiolytics and antidepressants on hormones of the HPA axis. The final section discusses stress-induced changes in the CNS.

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.

The dexamethasone suppression test and negative symptoms of schizophrenia

The dexamethasone suppression test (DST) was administered to 28 subjects who met DSM-III criteria for chronic schizophrenia and shared similar environments. Samples were assayed for both plasma cortisol and dexamethasone levels. After controlling for other factors, the mean postdexamethasone cortisol level (MPDC) was correlated with the patients' score on the Scale for the Assessment of Negative Symptoms (SANS). A significant relationship emerged between these 2 parameters, suggesting that the social deterioration seen in chronic schizophrenia is at least partly related to a biological disease process as reflected by the DST. The importance of quantifying the level of dexamethasone in the DST is discussed.

Cortisol response to a combined dexamethasone-human corticotrophin-releasing hormone challenge in patients with depression

Abstract We administered a combined dexamethasone-human corticotrophin-releasing hormone (hCRH) challenge test to 14 in-patients with a major depressive episode and to 14 age-matched controls. After pretreatment with 1.5 mg dexamethasone at 2300 h the day before, 100 mug hCRH was administered iv at 1500 h. Blood samples for cortisol determinations by radioimmunoassay were drawn at 1400 h, 1430 h and 1500 h before infusion of hCRH and thereafter every 15 min until 1700 h. Cortisol secretion after injection of hCRH assessed as area under the curve was significantly increased in patients with depression when compared to controls (14.5 +/- 4.3 ng x min x 1,000/ml vs 3.1 +/- 2.4 ng x min x 1,000/ml). Multiple regression analysis among patients revealed a significant impact of age and severity of depression upon hCRH-induced cortisol secretion, whereas in normal controls no significant influence of age on cortisol secretion after hCRH emerged. Our data show that in depressed patients hCRH evokes an escape from dexamethasone-induced suppression of the pituitary-adrenocortical activity, whereas it fails to do so among controls. This finding suggests that at the pituitary level the action of hCRH is enhanced by a factor that is less sensitive to dexamethasone suppression in depression. We postulate that this factor is vasopressin.

Psychoneuroendocrine research in depression. I. Hormone levels of different neuroendocrine axes and the dexamethasone suppression test

Psychoneuroendocrinology is of major importance in the biological research of depression. Most studies have focussed on the regulation of the hypothalamic-pituitary-adrenal (HPA) axis but other endocrine systems such as the hypothalamic-pituitary-thyroid (HPT), hypothalamic-pituitary-somatotropic (HPS), and the hypothalamic-pituitary-gonadal (HPG) axis have also been shown to be involved in the psychobiology of depression. There are close interrelations between various endocrine axes which possibly are affected during depressive illness. A variety of neuroendocrine abnormalities has been detected in depressive disorder but the pathophysiology of these derangements remains still unclear. Although the currently used neuroendocrine tests are not of diagnostic validity they may help to clarify the pathophysiological significance of the complex regulatory mechanisms of different neuroendocrine axes in affective disorders. Neuroendocrine regulation is determined both by peripheral and central mechanisms which both have to be adequately considered as well as potent interactions between various endocrine systems in further neuroendocrine depression research.

Cortisol secretion in adolescents with major depressive disorder

Plasma cortisol concentrations were determined every 20 min for 24 h, in a nonstressful environment, among 48 rigorously assessed, mostly outpatient, drug-free adolescent subjects during an episode of major depression (MDD) and among 40 normal adolescent subjects. There were no significant differences in the 24-h mean, peak, or nadir, or the time of the nocturnal rise, in plasma cortisol in the 2 groups. Analyses of different subgroups of MDD adolescents according to suicidality, severity of depression, separation anxiety, psychotic subtype, endogenicity, duration of episode, and sex also revealed no significant group differences. Only one adolescent (with MDD) was identified clearly as a hypersecretor of cortisol. These results indicate that abnormalities of spontaneous cortisol secretion are an unusual finding among adolescents with major depression when studied in a nonstressful environment.

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.

The plasma dexamethasone window: evidence supporting its usefulness to validate dexamethasone suppression test results

Two doses of dexamethasone (DEX) (0.5 and 1.0 mg) were administered in a randomized crossover design to 31 patients with major depression, 9 healthy controls, and 14 nondepressed psychiatric patients. Using this modified Dexamethasone Suppression Test (DST), minimum DEX levels of 6 nmol/liter at 8:00 AM and 2.0 nmol/liter at 4:00 PM were required to achieve reliable suppression of cortisol in healthy controls and nondepressed psychiatric patients. Failure to achieve these minimum plasma DEX levels was associated with similar rates of nonsuppression in both depressed and nondepressed patients, thereby reducing the specificity of the DST. Conversely, high DEX levels greater than 13 nmol/liter at 8:00 AM or 4.0 nmol/liter at 4:00 PM were associated with abnormal "suppressibility" in depressed patients, thereby reducing the sensitivity of the test. Controlling for plasma DEX concentrations by selecting a test result that fell within a plasma DEX window at 8:00 AM and 4:00 PM increased the sensitivity and specificity of the DST. Significant differences in plasma DEX between suppressors and nonsuppressors were no longer evident when comparing patients with adequate DEX levels, thus ensuring that cortisol escape reflected HPA axis changes associated with depression and not peripheral mechanisms responsible for the availability of DEX. These results suggest that the clinical utility of the DST would be significantly enhanced by extending the standard 1.0-mg DST and retesting those patients with levels outside the DEX window with a higher or lower dose. The data also indicate that the measurement of plasma DEX is essential to validly interpret DST status and highlight the need to standardize DEX assays to compare DST results between research centers.

Dexamethasone suppression test in dementia and depression. Clinical and biological correlates

To determine the usefulness of the DST in differentiating depression from dementia, the test was administered to three diagnostic groups of psychogeriatric patients: depression; dementia; and dementia with depression. Clinical assessments were supplemented by ratings on the HRSD and SCAG, as well as by EEG and CT. All three groups showed a high incidence of abnormal DST results unrelated to presence or severity of affective symptoms, but showing a better association with SCAG and its 'organic' subsets. The mechanism(s) underlying these abnormal results may reflect organic brain disease. The usefulness of the DST in differentiating depression from dementia in the elderly was not confirmed.

Specific determination of plasma dexamethasone by HPLC and RIA--application to standard dexamethasone suppression test in psychiatric patients

Three radioimmunoassays (RIA), with or without preparative HPLC, were applied to the monitoring of plasma dexamethasone (DXM) levels during standard dexamethasone suppression test (DST) in psychiatric patients. Due to the robotic ease of the fully automated HPLC process, precision of the chromatographic assay was equivalent to that of the direct assays, but prepurification improved both sensitivity and specificity. These improvements allowed the elucidation of the following features: (1) half (36) of the patients (68) displayed infranormal DXM levels (less than or equal to 0.40 ng/ml) whatever the cortisol response; (2) 22% (15) patients (68) with DXM levels in the low control range showed a strong inhibition of cortisol suppression. These observations raise some doubts on the validity of the DST test and introduce the following questions. (1) What is the dependence of cortisol suppression upon DXM absorption and catabolism? (2) Does plasma DXM measurement several hours after its physiological action still reflect its effect on the hypothalamo-hypophyseal axis? (3) What is the reliability of DXM direct assays when measuring low DXM levels in the presence of high cortisol?

Use of the dexamethasone suppression test in an inpatient setting: a replication and new findings

The dexamethasone suppression test (DST) was administered to 131 depressed and 109 nondepressed psychiatric inpatients. The depressed patients were categorized according to DSM-III as minor depression, major depression without melancholia, and major depression with melancholia and/or with psychotic features. The nondepressed patients were stratified over several DSM-III subcategories. DST nonsuppression was nonspecific for major depression: the mean post-dexamethasone cortisol value and the number of nonsuppressors were not significantly different between the major depressives and the nondepressed psychiatric controls. Within the depressive sample the DST was a significant (p less than 0.01) discriminator between major and minor depression. Postdexamethasone plasma greater than or equal to 3.5 micrograms/dl at 0800h was the most sensitive (39%) and specific (94%) criterion; cortisol values at 1600h and 2300h showed no significant discriminating power for major vs. minor depression. The diagnostic utility of the DST thus appears to be limited to confirming the diagnosis of major depression, once the clinical diagnosis of depression is made. There was no significant influence of age or gender on postdexamethasone cortisol values.

The dexamethasone suppression test: its relationship to diagnoses, severity of depression and response to treatment

1. The dexamethasone suppression test (DST) was applied to 40 depressed patients, 40 healthy volunteers and 40 patients with other psychiatric disorders. 2. The post-dexamethasone cortisol level, adopted as the non-suppression criterion and established locally, was 3.0 micrograms/dl. 3. The DST sensitivity in depression was 45%, with a specificity of 95% and a positive predictive value of 90%. 4. There was a significant correlation (r = 0.38, p less than 0.05) between HDRS scores of depressed patients and their post-dexamethasone cortisol levels. 5. A prospective study of the depressed group, which was assessed with three depression rating scales, showed differences between non-suppressors and suppressors regarding to the symptoms severity and response to the treatment. It suggests that an abnormal DST result could have a prognostic value to antidepressant drugs and ECT. 6. The DST specificity in depression was also calculated from its performance in the group with other psychiatric disorders, and their diagnoses as well as the abnormal DST results were critically discussed.

Triiodothyronine, thyroxine, and TSH response to dexamethasone in depressed patients and normal controls

In view of recent investigations concerning alterations of thyroid function in depression, the pre- and postdexamethasone levels of T3, T4, and TSH of 14 patients during depression and after recovery were studied, in addition to those of 27 healthy controls. A reduction of T3 and TSH levels was shown to be dependent on the depressive state, with a tendency to lower T4 levels after recovery. Dexamethasone had a pronounced suppressive effect on TSH levels in healthy controls and in patients after recovery, but not during the depressive episode. These results point to an inadequate suppressibility of the hypothalamo-pituitary-thyroid (HPT) axis to dexamethasone during depression. There are close interrelations between the hypothalamo-pituitary-adrenal (HPA) and the HPT axes that are possibly affected during depressive illness.

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.

Gonadal steroid and gonadotropin response to dexamethasone: a study in sexual dysfunction and normal controls

Numerous investigations have reported an alteration of hormonal response to dexamethasone in depressive disorder. No such data are available in psychogenic sexual dysfunction. Pre- and postdexamethasone levels of testosterone, estradiol, LH and FSH were studied in 20 male patients with sexual dysfunction and 20 male healthy controls. Dexamethasone had no influence on testosterone, estradiol, LH and FSH in normal controls. The patients showed an increase in testosterone and LH but not in FSH levels in the morning after dexamethasone administration. When compared with basal levels, the increase in postdexamethasone levels in sexual dysfunction was significant for testosterone (delta T) but not for LH (delta LH). The altered gonadal steroid and gonadotropin response to dexamethasone in sexual dysfunction might be due to disturbances of dexamethasone metabolism and glucocorticoid receptor density comparable to similar findings in depressive disorder.