Should the dexamethasone suppression test be resurrected?

Cortisol and the Dexamethasone Suppression Test as a Biomarker for Melancholic Depression: A Narrative Review

The dexamethasone suppression test (DST) assesses the functionality of the HPA axis and can be regarded as the first potential biomarker in psychiatry. In 1981, a group of researchers at the University of Michigan published a groundbreaking paper regarding its use for diagnosing melancholic depression, reporting a diagnostic sensitivity of 67% and a specificity of 95%. While this study generated much enthusiasm and high expectations in the field of biological psychiatry, subsequent studies produced equivocal results, leading to the test being rejected by the American Psychiatric Association. The scientific reasons leading to the rise and fall of the DST are assessed in this review, suggestions are provided as to how the original test can be improved, and its potential applications in clinical psychiatry are discussed. An improved, standardized, and validated version of the DST would be a biologically meaningful and useful biomarker in psychiatry, providing a tool for clinicians caring for depressed patients in the areas of diagnosis, treatment, and prognosis, and predicting the risk of suicide. Additionally, such a test could be a crucial part in the generation of biologically homogenous patient cohorts, necessary for the successful development of new psychotropic medications.

The association of electroconvulsive therapy to pharmacological treatment and its influence on cytokines

INTRODUCTION

A growing body of evidence shows that disturbances in the immune system are involved in the pathogenesis of depression. Although the immune-modulating effects of antidepressants have been described, few studies have addressed the functioning of the immune system in relation to electroconvulsive therapy (ECT). This study aims to investigate if the addition of ECT to pharmacotherapy is associated with changes in cytokine levels.

METHODS

Adult inpatients were invited to participate in this study on admission to a psychiatric unit. Those with a diagnosis of depression by Mini-International Neuropsychiatric Interview were included. At treatment discharge, patients were retrospectively divided into those who used combined ECT and pharmacotherapy (31 subjects) and those who used only pharmacotherapy (68 subjects). Pro-inflammatory cytokines IL-2, IL-6, TNF-α, IFN-γ, and IL-17, and anti-inflammatory IL-4 and Il-10, were measured in blood samples collected at admission and discharge. A generalized estimating equation model and the post hoc Bonferroni test were performed for statistical analysis.

RESULTS

The combination of ECT with pharmacotherapy was associated with a decrease of IL-6 and an increase of TNF-α. Depressive inpatients, as a whole group, had a decrease of IL-6 and an increase of IFN-γ. No significant results were found for IL-2, IL-4, Il-10 and IL-17.

CONCLUSION

This study is clinically relevant because we highlight that, in agreement with the previous literature, IL-6 appears to be a useful marker in depression, and we show for the first time that its reduction is closely related to the use of ECT.

Levels of serum immunomodulators and alterations with electroconvulsive therapy in treatment-resistant major depression

Studies in recent years have indicated that neuroimmunological events and immune activation may have a place in the etiology of depression. It has been suggested from data that there is a causal relationship between activation of the immune system and excessive release of proinflammatory cytokines, such as interleukin 1 (IL-1), IL-6, and tumor necrosis factor-alpha (TNF-alpha), and the etiology of depression. Although the mechanism of action of electroconvulsive therapy (ECT) is unclear, there is evidence that it can reduce cytokines and immune system changes. In our study, we aimed to determine how levels of serum immunomodulators were affected by ECT in major depression patients. This study was conducted on 50 patients with treatment-resistant major depression. The data of the patients were compared with 30 healthy individuals with similar demographic characteristics. A clinical response occurred in the patients and at the end of therapy, IL-1, IL-6, TNF-alpha, IL-10, IL-4, and interferon-gamma levels were measured. The disease severity was assessed with the 17-item Hamilton Depression Rating Scale. Data analysis was performed using SPSS Version 15. Significant differences were determined between the patients with major depression and control group with respect to basal serum IL-1, IL-6, TNF-alpha, IL-10, IL-4, and interferon-gamma levels. ECT treatment was shown to reduce these differences. ECT may cause significant changes in the activity of the immune system. The consideration of the relationship between the immune endocrine neurotransmitter systems could contribute to new theories regarding the mechanism of antidepressant treatment and biology of depression.

Relationship of temperament and character with cortisol reactivity to the combined dexamethasone/CRH test in depressed outpatients

BACKGROUND

Evidence shows that depression is associated with hypothalamic-pituitary-adrenal (HPA) axis hyperactivation, although such findings are not entirely unequivocal. In contrast, various psychiatric conditions, including atypical depression, are associated with hypocortisolism. Another line of research has demonstrated that personality is associated with HPA axis alteration. It is thus hypothesized that different personality pathology in depression would be associated with distinct cortisol reactivity.

METHODS

Eighty-seven outpatients with DSM-IV major depressive disorder were recruited. Personality was assessed by the temperament and character inventory (TCI). HPA axis reactivity was measured by the combined dexamethasone (DEX)/corticotropin-releasing hormone (CRH) test. According to our previous studies, two subgroups were considered based on their cortisol responses to the DEX/CRH test: incomplete-suppressors whose cortisol response was exaggerated and enhanced-suppressors whose cortisol response was blunted.

RESULTS

The analysis of covariance, controlling for age, gender and symptom severity, revealed that incomplete-suppressors scored significantly higher on cooperativeness than enhanced-suppressors (p=0.002). A multivariate stepwise logistic regression analysis predicting the cortisol suppression pattern from the seven TCI dimensions, controlling for age, gender and symptom severity, revealed that lower cooperativeness (p=0.001) and higher reward dependence (p=0.018) were significant predictors toward enhanced suppression.

LIMITATIONS

The neuroendocrine challenge test was administered only once, based on a simple test protocol.

CONCLUSIONS

Our findings suggest that (personality-related) subtypes of depression might be differentiated based on the different pattern of cortisol reactivity. Future studies are warranted to further characterize the HPA axis alteration in relation to various subtypes of depression.

Post-dexamethasone cortisol as a predictor for the efficacy of electroconvulsive therapy in depressed inpatients

BACKGROUND

Although several variables have been studied as a possible predictor for the efficacy of ECT, results regarding hypercortisolism have been inconsistent. This prospective study evaluates the relation between pre-treatment cortisol levels and the efficacy of ECT in a population of drug-free inpatients with severe major depression.

METHODS

At the inpatient depression unit, 18 patients meeting the DSM-IV criteria for depressive disorder, and with scores of at least 18 on the 17-item Hamilton Rating Scale for Depression (HAM-D), were treated with bilateral ECT twice weekly. The HAM-D evaluated depression severity and was performed within 3 days prior to ECT, weekly during the course of ECT, and within 3 days after the last treatment. The outcome criterion was defined a priori as the change on the HAM-D score. Salivary cortisol was assessed within 3 days prior to ECT at two time points, followed by 0.5 mg dexamethasone ingestion. The following day, salivary cortisol was again assessed at two time points. The generalized linear model was used to assess the relation between salivary cortisol levels and reduction in HAM-D score as continuous variables.

RESULTS

Higher levels of salivary cortisol at 9 AM after 0.5 mg dexamethasone ingestion are associated with a greater reduction in HAM-D score (B = -0.279, 95% CI: -0.557 to -0.01, s.e. = 0.13, p = 0.049; R square = 0.23; adjusted R square = 0.13).

CONCLUSION

This study suggests that higher levels of post-dexamethasone salivary cortisol at 9 AM are predictive of ECT efficacy.

Does the dexamethasone suppression test reliably discriminate between psychotic and nonpsychotic major depression?: an exploratory analysis of potential confounds

Previous research has shown that psychotic major depression (PMD) is often associated with higher rates of nonsuppression on the dexamethasone suppression test (DST) compared with nonpsychotic major depression (NMD), suggesting the potential importance of cortisol hypersecretion in the psychotic subtype of the disorder. However, these patient groups also are known to differ from one another on a variety of other clinical variables, and there are numerous factors independent of diagnostic status known to affect the DST. Thus, we investigated possible confounds that could help account for the apparent DST abnormalities in PMD sometimes reported in past research. Hospitalized patients with PMD (n = 11) and NMD (n = 58) were compared on the DST and other clinical variables. As expected, PMD patients showed significantly higher rates of DST nonsuppression (55% vs. 24%; p = 0.04). However, PMD patients also had significantly higher levels of anxiety severity (p = 0.01). The higher rates of nonsuppression in the PMD group were attenuated when these patients were compared with a subsample of NMD patients matched on anxiety severity (55% vs. 55%). Implications for future research on biological markers of PMD are discussed.

Treatment-resistant depression: critique of current approaches

The aim of the present study was to critically appraise current conceptual approaches; demographic, neurobiological and clinical correlates; and management strategies of treatment-resistant depression (TRD), especially in light of recent research findings. To this end, a review of the relevant English-language literature was undertaken using Medline, Embase and Psychinfo. TRD has been defined in conceptually restrictive terms as symptomatic non-response to physical therapies alone, with little systematic study of aetiology made. It is likely that a range of sociodemographic (such as higher socioeconomic status), genetic (such as variation in functional monoamine polymorphisms) and clinical variables (such as signal hyperintensities seen on structural neuroimaging scans) are responsible for non-response in individuals. There is insufficient evidence to suggest that TRD is associated with specific subtypes of depression, physical comorbidity, personality or chronicity. The large-scale Sequenced Treatment Alternatives to Relieve Depression (STAR*D) and other studies have suggested that a structured psychotherapy such as cognitive behaviour therapy may be as effective as medication in initial drug non-responders. Also conventional alternatives such as the use of older antidepressant classes, pharmacological augmentation or electroconvulsive therapy in established cases of TRD are not as effective as traditionally thought. There is insufficient preliminary evidence to make formal recommendations about the use of novel brain stimulation techniques in TRD. TRD should be re-defined as the failure to reach symptomatic and functional remission after adequate treatment with physical and psychological therapies. Treatment resistance may be more usefully conceived within the context of well-defined cohorts such as patients with specific subtypes of depression. Although neurobiological markers such as gene polymorphisms, which are potentially predictive of medication tolerance and efficacy, may be used in the future, it is likely that sociocultural variables such as beliefs about depression, and evidence-based treatments for it, will also determine treatment resistance.

Restoring melancholia in the classification of mood disorders

The present DSM criteria for major depression poorly identify samples for treatment selection, prognosis, and assessments of pathophysiology. Melancholia, in contrast, is a disorder with definable clinical signs that can be verified by laboratory tests and treatment response. It identifies more specific populations than the present system and deserves individual identification in psychiatric classification. Its re-introduction will refine diagnosis, prognosis, treatment selection, and studies of pathophysiology of a large segment of the psychiatrically ill.

Corticotropin-releasing factor (CRF) in stress and disease: a review of literature and treatment perspectives with special emphasis on psychiatric disorders

The CRF family of neuropeptides and receptors is involved in a variety of stress responses, in the regulation of appetite, metabolic and inflammatory processes as well as intestinal movements. From a primarily psychiatric perspective, the present paper reviews the literature on its anatomy, physiology and its involvement in psychiatric, neurological and inflammatory diseases. Finally, recent developments in the pharmacological aspects of CRF in these diseases are reviewed.

Findings with 0.25 mg dexamethasone suppression test in eating disorders: association with childhood trauma

INTRODUCTION

While both blunted and enhanced cortisol suppression following a dexamethasone suppression test (DST) are described in eating disorders, some evidence suggests that enhanced cortisol suppression might be associated with the presence of trauma history. The objective of this study is to investigate hypothalamic-pituitary-adrenal axis response to a modified DST in eating disorders and its relationship with childhood trauma.

METHODS

Fifty-two patients with eating disorders were studied with a 0.25 mg DST and with measures of childhood trauma.

CONCLUSION

Patients with bulimia symptoms had significantly greater cortisol suppression than controls and restrictive anorexia patients (F=8.2, P<.05). Cortisol suppression was significantly correlated with intensity of childhood traumatic events (F=0.32, P<.05). Hypersensitive hypothalamic-pituitary-adrenal axis response to DST in eating disorders may be related with a history of childhood trauma and suggests some biological similarities with posttraumatic syndromes that should be further explored.

DST non-suppression predicts suicide after attempted suicide

Most prospective studies of HPA axis have found that non-suppressors in the dexamethasone suppression test (DST) are more likely to commit suicide during the follow-up. Attempted suicide is a strong clinical predictor of suicide. The aim of this study was to assess the predictive value of DST for suicide in a group of depressed inpatients with and without an index suicide attempt. Historical cohort of 382 psychiatric inpatients with mood disorder admitted to the department of Psychiatry at the Karolinska University Hospital between 1980 and 2000 were submitted to the DST and followed up for causes of death. During the follow-up (mean 18 years), 36 suicides (9.4%) occurred, 20 of these were non-suppressors and 16 were suppressors. There was no statistically significant difference in suicide risk between the suppressors and non-suppressors for the sample as a whole. An index suicide attempt predicted suicide. In suicide attempters with mood disorder, the non-suppressor status was significantly associated with suicide indicating that HPA axis hyperactivity is a risk factor for suicide in this group. The dexamethasone suppression test may be a useful predictor within this population.

Resurrecting melancholia

OBJECTIVE

To define melancholia as a distinct mood disorder, identified by unremitting depressed mood, vegetative dysfunction, and psychomotor disturbances, verifiable by neuroendocrine tests, and treatable by electroconvulsive therapy and tricyclic antidepressants.

METHOD

A review of the literature of two centuries finds descriptions of severe mood disorders, either depression or mania or circular, defined as 'melancholia.' In the 1980 diagnostic revision (DSM-III), melancholia was relegated to a features specifier only.

RESULTS

DSM classification criteria develop heterogeneous patient samples that are neither guides to prognosis nor to treatment response, and confound studies of pathophysiology. Within the large population of mood disorders, a syndrome of melancholia is identifiable by specific behaviors, vegetative signs, and validated by neuroendocrine abnormalities (cortisolemia). Populations so identified are clinically homogeneous and have improved treatment responses. Patients meeting criteria for melancholia are now identified as psychotic depressed, geriatric depressed, postpartum psychosis, and pharmacotherapy resistant.

CONCLUSION

The review supports the establishment of melancholia by empirically derived criteria rather than by a checklist is an alternative to the major depression choice and offers an improved model for psychiatric classification.

The case against evidence-based principles in psychiatry

There is an organized movement by governmental, academic and commercial interests to make evidence-based practice the standard of care in the United States. There is little proof that this model can be adapted to psychiatry. We examine the diagnostic system, the validity of the data from clinical trials and how these are applied to clinical practice. The discipline of psychiatry relies on imprecise and unstable diagnostic criteria. It divides psychiatric disorders into discrete categories based on discussion and consultations among designated experts in the field. The diagnostic system is based on consensus and not experimental evidence. In fact, psychiatric disorders are not discrete. High co-morbidities between disorders and the propensity of one condition to change into another makes the present diagnostic system extremely questionable. Outcomes of clinical trials are defined by fractional reductions in the number and severity of symptoms measured by rating scales and not remission of illness. The data obtained from clinical trials are flawed in design, execution and the selective reporting of outcomes. There is substantial evidence to indicate that both investigators and patients can distinguish between active treatment and placebo in double blind studies. In addition, negative outcomes are frequently not reported. Such evidence impacts not only on the specific study, used as evidence, but invalidates the value of meta analyses. Financial considerations lead to the inclusion of inappropriate subjects into studies and favor newer, patented treatments. When the conclusions derived from evidence-based psychiatry are applied to clinical practice they have little to offer and often produce poor treatment outcomes. In fact, when the data used to support the principles of evidence-based psychiatry are examined, they are unsound. The system itself is best considered an untested hypothesis. The diagnostic system, the manner in which data are gathered, and financial factors combine to produce a system that is misleading and indeed, dangerous.