Clinical outcome after trimipramine in patients with delusional depression - a pilot study

Tools for optimising pharmacotherapy in psychiatry (therapeutic drug monitoring, molecular brain imaging and pharmacogenetic tests): focus on antidepressants

Objectives: More than 40 drugs are available to treat affective disorders. Individual selection of the optimal drug and dose is required to attain the highest possible efficacy and acceptable tolerability for every patient.Methods: This review, which includes more than 500 articles selected by 30 experts, combines relevant knowledge on studies investigating the pharmacokinetics, pharmacodynamics and pharmacogenetics of 33 antidepressant drugs and of 4 drugs approved for augmentation in cases of insufficient response to antidepressant monotherapy. Such studies typically measure drug concentrations in blood (i.e. therapeutic drug monitoring) and genotype relevant genetic polymorphisms of enzymes, transporters or receptors involved in drug metabolism or mechanism of action. Imaging studies, primarily positron emission tomography that relates drug concentrations in blood and radioligand binding, are considered to quantify target structure occupancy by the antidepressant drugs in vivo. Results: Evidence is given that in vivo imaging, therapeutic drug monitoring and genotyping and/or phenotyping of drug metabolising enzymes should be an integral part in the development of any new antidepressant drug.Conclusions: To guide antidepressant drug therapy in everyday practice, there are multiple indications such as uncertain adherence, polypharmacy, nonresponse and/or adverse reactions under therapeutically recommended doses, where therapeutic drug monitoring and cytochrome P450 genotyping and/or phenotyping should be applied as valid tools of precision medicine.

Impact on cortisol and antidepressant efficacy of quetiapine and escitalopram in depression

BACKGROUND

In this study, the impact of quetiapine fumarate extended release (QXR) and escitalopram (ESC) on HPA axis activity was investigated in depressed patients in relationship to antidepressant efficacy.

METHODS

In a randomized, open-label 5-week trial 60 inpatients suffering from major depression (DSM-IV criteria) were treated for 5 weeks with either QXR (300 mg/day) or ESC (10mg/day). The dexamethasone/CRH (DEX/CRH) test was performed before treatment, after 1, and after 5 weeks of treatment. Cortisol (COR) AUC values were used to assess HPA axis function. The Hamilton Depression Rating Scale was used weekly to estimate antidepressant efficacy.

RESULTS

QXR and ESC showed comparable antidepressant effects but strongly differed in their impact on HPA axis activity. In the QXR group, a marked inhibition of COR AUC levels was observed which was most pronounced after one week of treatment but showed a partial re-increase after 5 weeks of treatment. In contrast, ESC transiently stimulated COR AUC values (week 1) whereas COR AUC levels at week 0 and week 5 were comparable. COR improvement at week 1 (defined as COR peak value reduction between DEX/CRH test 1 and 2) was significantly associated with better clinical outcome.

CONCLUSION

Apparently, different effects on HPA axis activity reflect distinct pharmacoendocrinological properties of psychotropic drugs.

Impact of citalopram on the HPA system. A study of the combined DEX/CRH test in 30 unipolar depressed patients

BACKGROUND

Dysregulation of the hypothalamic-pituitary-adrenocortical (HPA) system is one of the best replicated pathophysiological findings in depression. However, studies on the influence of treatment on the HPA system have partly yielded inconsistent results.

OBJECTIVE

To assess the effects of citalopram monotherapy on the HPA system of mainly drug naïve patients with major depression by means of the combined DEX/CRH test.

METHODS

The DEX/CRH test was conducted twice in 30 patients (25 drug naïve for the index episode) with major depression (single episode or unipolar recurrent; SCID I- and II-confirmed): directly before the start of a citalopram monotherapy (day 0) and four weeks thereafter (day 28).

RESULTS

Twenty-three patients responded (≥50% reduction in the HDRS(21)-score), and 17 of them also reached criteria of remission (HDRS ≤ 7). Baseline (dexamethasone-suppressed) and CRH-stimulated ACTH concentrations significantly decreased from day 0 to day 28. CRH-stimulated cortisol concentrations also fell, although not significantly, but baseline cortisol concentrations exhibited a significant increase from day 0 to day 28.

CONCLUSIONS

The blunting of the ACTH response in the DEX/CRH test under citalopram is in line with what has been observed in most studies with antidepressants. However, the partial rise in cortisol concentrations indicates an increase in the sensitivity of the adrenal cortex to ACTH. State-dependent alterations in the volume and the ACTH responsiveness of the adrenal gland have repeatedly been reported in depressed subjects, which indicates the possibility that SSRIs such as citalopram might exhibit a direct or indirect effect on the adrenal cortex.

Lithium monotherapy increases ACTH and cortisol response in the DEX/CRH test in unipolar depressed subjects. A study with 30 treatment-naive patients

BACKGROUND

Distorted activity of the hypothalamic-pituitary-adrenocortical (HPA) system is one of the most robustly documented biological abnormalities in major depression. Lithium is central to the treatment of affective disorders, but little is known about its effects on the HPA system of depressed subjects.

OBJECTIVE

To assess the effects of lithium monotherapy on the HPA system of patients with major depression by means of the combined DEX/CRH test.

METHOD

Thirty drug-naive outpatients with major depression (single episode or unipolar recurrent; SCID I- and II-confirmed) were treated with lithium monotherapy for four weeks. The DEX/CRH test was conducted directly before intake of the first lithium tablet and four weeks thereafter. Weekly ratings with the HDRS(21) were used to determine response (≥50% symptom reduction) and remission (HDRS ≤7).

RESULTS

Lithium levels within the therapeutic range were achieved rapidly. Tolerability was good; no patient terminated the treatment prematurely. Response and remission rates were 50% and 33% respectively. Compared to the DEX/CRH test before the start of the treatment, a considerable and significant increase in all CRH-stimulated ACTH and cortisol parameters could be detected in the second DEX/CRH test. When analysed with particular regard to responders and non-responders, that significant increase was only present in the responders.

CONCLUSIONS

We were able to demonstrate that lithium leads to a significant activation of the HPA system. This is possibly connected to stimulation of hypothalamic arginine vasoporessin (AVP), to direct intracellular effects of lithium on pituitary cells and to an induction of gene expression.

TRIAL REGISTRATION

drks-nue.uniklinik-freiburg.de DRKS00003185.

Glucocorticoids as predictors of treatment response in depression

INTRODUCTION

Glucocorticoids and the stress hormone system have been implicated in the pathophysiology of depression and in the mechanism of action of antidepressant response. Many studies have investigated this system in an effort to predict response to antidepressant treatment. The purpose of this review is to evaluate the evidence for using glucocorticoid-related measures for personalized treatment of depression.

METHODS

We conducted a MEDLINE search from 1966 through 2010 and examined English-language studies reporting on the use of endocrine challenge tests and genetic polymorphisms in genes regulating the stress hormone system as predictors of antidepressant response.

RESULTS

While measures of glucocorticoid levels using endocrine tests, as well polymorphisms in genes regulating the stress hormone system, show associations with response to antidepressant treatment, these measures will need to be combined with other variables, including clinical information and other biological measures, to realize the goal of highly predictive and clinically relevant biomarkers.

DISCUSSION

The glucocorticoid system is potentially of great use in predicting antidepressant response. New combinations of biomarkers including these measures should be tested to develop clinically relevant predictors.

A single DEX/CRH test in male drug-free depressed patients is associated with the clinical response to treatment with fluoxetine

OBJECTIVES

The DEX/CRH test has been proposed to be suitable as a biomarker for the prediction of treatment response in depression.

METHODS

We performed the DEX/CRH test in 10 severely depressed male patients with melancholic features before initiation of antidepressant treatment with 20 mg fluoxetine.

RESULTS

We found a low cortisol response (as measured by cortisol AUC) to a single DEX/CRH test to be associated with clinical response to treatment.

CONCLUSIONS

A strength of this study lies in the inclusion of patients after a drug wash-out phase. Despite a certain inconsistency described in the literature, several studies support the notion that it might be of importance to measure baseline HPA system activity before choice of treatment. Further systematic studies are warranted.

Outcome in delusional depression comparing trimipramine monotherapy with a combination of amitriptyline and haloperidol--a double-blind multicenter trial

BACKGROUND

Patients with delusional depression are difficult to treat. The atypical antidepressant trimipramine was effective in a previous 4-week open label pilot study in patients with this disorder. The major neurobiological effect of trimipramine is the inhibition of the hypothalamic-pituitary-adrenocortical (HPA) system. In delusional depression HPA overactivity is more distinct than in other subtypes of depression. HPA suppression is thought to contribute to the action of trimipramine.

METHODS

In a double-blind, randomized, placebo controlled multicenter trial we compared the effects of trimipramine monotherapy versus a combination of amitriptyline and haloperidol. Dosage was increased stepwise from 100mg up to 400mg trimipramine and from 100mg up to 200mg amitriptyline combined with 2mg up to 7.5mg haloperidol. The average dose of trimipramine was higher than that of amitriptyline throughout the trial. During sixth week mean dosage (+/-standard deviation) were 356.1+/-61.2mg trimipramine, 184.0+/-23.6 mg amitriptyline and 6.3+/-1.8 mg haloperidol. During six weeks psychometric assessments were performed weekly. For HPA monitoring a dexamethasone/corticotropin-releasing hormone (Dex/CRH) test was performed before active medication and at the end of treatment. Additionally tolerability was monitored by ECG, EEG assessment of extrapyramidal symptoms and akathisia, clinical laboratory routine and recording of blood pressure and heart rate. Adverse events were documented.

RESULTS

94 patients were enclosed into the study. The per protocol sample consisted of 33 patients of the trimipramine group and of 24 patients of the amitriptyline/haloperidol group. The decrease of the Hamilton depression (HAMD) score (24 items) showed non-inferiority of trimipramine compared to amitriptyline/haloperidol. Twenty-eight patients (84.84%) in the trimipramine arm and 17 patients (70.83%) in the amitriptyline/haloperidol arm were responders (HAMD <or=50%). Remission (HAMD<8) was found in 18 (54.55%) patients after trimipramine and in 11 (45.83%) patients after amitriptyline/haloperidol. No significant differences were found concerning response and remission. The cortisol and ACTH response in the Dex/CRH test decreased between days 1 and 42 in both groups. Serious side effects were not reported.

CONCLUSION

In all, trimipramine monotherapy appears to be an effective treatment in delusional depression.

Suppressive effect of mirtazapine on the HPA system in acutely depressed women seems to be transient and not related to antidepressant action

Impaired regulation of the hypothalamus-pituitary-adrenocortical (HPA) system is a consistent finding among patients with depression, which can be most sensitively detected with the combined dexamethasone (dex)/corticotrophin releasing hormone (CRH) test. The majority of patients with acute depression shows an exaggerated plasma corticotrophin (ACTH) and cortisol response to this test that normalizes gradually during successful antidepressant therapy. In contrast, persistently high HPA-responses to this challenge are prognostically less favorable. It has been recently questioned, whether this observation applies also to treatment with the atypical antidepressant mirtazapine, as patients treated with this drug showed a distinct attenuation of the endocrine response to the dex/CRH test already after 1 week of treatment. In the present study, we investigated whether the attenuating effect of mirtazapine on the HPA system is an acute pharmacological reaction disappearing after physiological adaptation or whether this effect is related to the antidepressant action of the drug. We examined plasma ACTH and cortisol responses to the dex/CRH test in acutely depressed inpatients treated either with mirtazapine (n=55) or a monoamine reuptake inhibitor (n=105) according to doctor's choice and compared the test results with healthy controls (n=40). Patients treated with monoamine reuptake inhibitors received either selective serotonin reuptake inhibitors (SSRI), tricyclic antidepressants (TCA) or the combined serotonin and noradrenalin reuptake inhibitor venlafaxine. We found increased plasma ACTH and cortisol responses to the dex/CRH test in depressed patients compared with healthy controls, but also significantly (p=.017) attenuated plasma cortisol secretion in the mirtazapine group compared to the group of monoamine reuptake inhibitor treated patients. This effect was not significant in male patients. Furthermore this effect was independent of the psychopathological state, but depended on treatment duration. Patient treatment with mirtazapine for up to 7 days resulted in dex/CRH test outcome that was indistinguishable from controls. This effect, however waned as it was not observable in patients treated for a longer period. These results suggest that short-term administration of mirtazapine has immediate but only transient suppressive effects on the HPA system predominantly in women. Our results confirm that dex/CRH tests can be used as predictors of clinical course also under mirtazapine treatment.

The combined dexamethasone/CRH Test (DEX/CRH test) and prediction of acute treatment response in major depression

Background

In this study the predictive value of the combined dexamethasone/CRH test (DEX/CRH test) for acute antidepressant response was investigated.

Methodology/Principal Findings

In 114 depressed inpatients suffering from unipolar or bipolar depression (sample 1) the DEX/CRH test was performed at admission and shortly before discharge. During their stay in the hospital patients received different antidepressant treatment regimens. At admission, the rate of nonsuppression (basal cortisol levels >75.3 nmol/l) was 24.6% and was not related to the later therapeutic response. Moreover, 45 out of 114 (39.5%) patients showed an enhancement of HPA axis function at discharge in spite of clinical improvement. In a second sample, 40 depressed patients were treated either with reboxetine or mirtazapine for 5 weeks. The DEX/CRH test was performed before, after 1 week, and after 5 weeks of pharmacotherapy. Attenuation of HPA axis activity after 1 week was associated with a more pronounced alleviation of depressive symptoms after 5-week mirtazapine treatment, whereas downregulation of HPA system activity after 5 weeks was related to clinical response to reboxetine. However, early improvement of HPA axis dysregulation was not necessarily followed by a beneficial treatment outcome.

Conclusions/Significance

Taken together, performance of a single DEX/CRH test does not predict the therapeutic response. The best predictor for response seems to be an early attenuation of HPA axis activity within 1 or 2 weeks. However, early improvement of HPA system dysfunction is not a sufficient condition for a favourable response. Since a substantial part of depressive patients display a persistence of HPA axis hyperactivity at discharge, downregulation of HPA system function is not a necessary condition for acute clinical improvement either. Our data underline the importance of HPA axis dysregulation for treatment outcome in major depression, although restoration of HPA system dysfunction seems to be neither a necessary nor a sufficient determinant for acute treatment response.

Dex/CRH-test response and sleep in depressed patients and healthy controls with and without vulnerability for affective disorders

Sleep electroencephalographic (EEG) abnormalities and increased hypothalamo-pituitary-adrenal (HPA) axis activity are the most prominent neurobiological findings in depression and were suggested as potential biomarker for depression. In particular, increased rapid eye movement sleep (REM) density, deficit in slow wave sleep and excessive stress hormone response are associated with an unfavorable long-term outcome of depression. Recent studies indicate that the sleep and endocrine parameters are related to each other. This study investigated the association of sleep structure including a quantitative EEG analysis with the results of the combined dexamethasone (Dex)/corticotropin-releasing hormone (CRH)-test in 14 patients with a severe major depression, 21 healthy probands with a positive family history of depression (HRPs) and 12 healthy control subjects without personal and family history for psychiatric disorders. As expected patients with depression showed an overactivity of the HPA axis, disturbed sleep continuity and prolonged latency until slow wave sleep in the first sleep cycle. Differences in microarchitecture of sleep were less prominent and restricted to a higher NonREM sigma power in the HRP group. Dexamethasone suppressed cortisol levels were positively associated with higher NonREM sigma power after merging the three groups. We also observed an inverse association between the ACTH response to the Dex/CRH-test and rapid eye movement sleep (REM) density in HRPs, with suggestive evidence also in patients, but not in controls. This contra-intuitive finding might be a result of the subject selection (unaffected HRPs, severely depressed patients) and the complementarity of the two markers. HRPs and patients with high disease vulnerability, indicated by an elevated REM density, seem to have a lower threshold until an actual disease process affecting the HPA axis translates into depression, and vice versa. To summarize, our findings provide further evidence that the HPA axis is involved in the sleep regulation in depression. These associations, however, are not unidimensional, but dependent on the kind of sleep parameters as well as on the selection of the subjects.

Metabolism in adipose tissue in response to citalopram and trimipramine treatment--an in situ microdialysis study

The intake of antidepressants is often accompanied by weight gain. Antidepressants may influence lipid and carbohydrate metabolism that can result in metabolic changes and obesity. We investigated the effect of citalopram and trimipramine on interstitial glycerol, glucose and lactate concentration and blood flow in subcutaneous adipose tissue of obese subjects by means of the microdialysis technique. In addition, the effect of stimulation with norepinephrine on metabolic response was investigated. Each subject was compared to a control subject matched for BMI and age. Each group comprised 10 subjects. Circulating plasma triglyceride concentrations were higher in drug-treated groups. In subcutaneous adipose tissue, microdialysis experiments revealed a higher and prolonged glycerol release in the presence of norepinephrine, but not under basal conditions. In citalopram treated subjects, basal glucose and lactate concentrations were higher compared with controls or with the trimipramine treated group. Local administration of norepinephrine induced a decrease in glucose levels and an increase in lactate levels, but without significant differences between groups. Local adipose tissue blood flow decreased in control groups following norepinephrine application, but remained constant in the antidepressant groups. In conclusion, citalopram and trimipramine affected glucose and lipid metabolism in adipose tissue and resulted in enhanced release of glycerol and free fatty acids into the circulation.

Risk of psychosis exacerbation by tricyclic antidepressants in unipolar Major Depressive Disorder with psychotic features

BACKGROUND

We conducted a systematic review of the published trials in unipolar Major Depressive Disorder with psychotic features (MDDP) to examine the risk of psychosis exacerbation by antidepressants.

METHODS

We searched Medline, Cochrane Central Register of Controlled Trials, PsychINFO, and EMBASE for English language, controlled, open or retrospective acute antidepressant and/or antipsychotic treatment studies of unipolar MDDP. Studies without a clear delineation of treatment course or between bipolar disorder and unipolar MDDP were excluded. We evaluated studies for the number of subjects with psychosis exacerbation, and contacted the corresponding author for ambiguous cases. Studies in which we were unable to determine rates of psychosis exacerbation were excluded. Psychosis exacerbation was determined on a categorical basis, and analyzed with Fisher's exact test, a modified Wald confidence interval and odds ratio.

RESULTS

20 studies meeting criteria provided sufficient adverse event reporting for inclusion. 15 of 177 subjects (8.5%) on antidepressant monotherapy had a psychosis exacerbation, 8 of whom were on tricyclics. 2 of 129 subjects on either antipsychotic or combination treatment had a psychosis exacerbation. Tricyclic monotherapy was significantly more likely to be temporally associated with psychosis exacerbation (p=0.007).

LIMITATIONS

Limitations include the small number of placebo-controlled trials, and numerous studies in which the relevant information was missing. Additionally, most trials were designed as treatment outcome studies, and not to determine the rate of psychosis exacerbation.

CONCLUSIONS

Although rare, the present study indicates that tricyclic monotherapy may be temporally associated with an exacerbation of psychotic symptoms in patients with unipolar MDDP, potentially worsening prognosis.

Longitudinal neuroendocrine changes assessed by dexamethasone/CRH and growth hormone releasing hormone tests in psychotic depression

Although psychotic depression has been reported to exhibit a greater degree of dysregulation of hypothalamic-pituitary-adrenocortical (HPA) function than non-psychotic depression, little is known concerning hypothalamic-pituitary-somatotropic (HPS) function in psychotic depression and how neuroendocrine function changes after treatment. To investigate the longitudinal changes in HPA and HPS system function in psychotic depression, we performed repeated dexamethasone/corticotropin releasing hormone (DEX/CRH) tests and growth hormone (GH) releasing hormone (GHRH) tests in inpatients with major depressive disorder. The psychotic depression group exhibited greater elevation of ACTH responses to the DEX/CRH test and stronger decreases in GH responses to the GHRH test than the non-psychotic depression group at admission. At discharge, the neuroendocrine responses to the DEX/CRH test of the psychotic depression group were still stronger than those of the non-psychotic depression group, though there were no significant differences in severity of depression between the groups. There were significant longitudinal changes in neuroendocrine responses to the DEX/CRH test between admission and discharge. The psychotic depression group exhibited increased GH responses to GHRH at discharge compared with those at admission, whereas no significant longitudinal change in GH response was found in the non-psychotic depression group. Consequently, there were no significant differences in GH responses to GHRH between the psychotic and non-psychotic depression groups at discharge. The results of GHRH test showed no significant relationships with severity of depression except psychotic features and the results of the DEX/CRH test. Our findings suggest that the HPS axis may be associated with psychotic features rather than general severity of depression. Further longitudinal studies are needed to clarify the role of HPS function in psychotic depression and whether sustained dysregulation of HPA function in psychotic depression is associated with a poor outcome after discharge.

Combined dexamethasone/corticotropin releasing hormone test predicts treatment response in major depression - a potential biomarker?

BACKGROUND

Exaggerated corticotropin (ACTH) and cortisol response to the combined dexamethasone (DEX)/corticotropin releasing hormone (CRH) test, indicating impaired regulation of the hypothalamus-pituitary-adrenocortical (HPA) system, is frequently observed in depression. In the present study, we examined whether change in HPA system function during the first weeks of hospitalization predicts response to antidepressant treatment in major depression and thus constitutes a potential biomarker.

METHODS

We conducted the DEX/CRH test in 50 inpatients suffering from severe major depression, once after study inclusion and a second time 2 to 3 weeks later while under continuous antidepressant treatment.

RESULTS

We found increased ACTH and cortisol responses to the first DEX/CRH test compared with healthy control subjects. In the second DEX/CRH test 2 to 3 weeks later, 36 of the 50 patients showed an attenuated cortisol response, while 14 patients did not display improvement or exhibited even aggravation of the altered HPA system function. Improved HPA system regulation in the second DEX/CRH test was associated with beneficial treatment response after 5 weeks and a higher remission rate at the end of hospitalization.

CONCLUSIONS

The results suggest that change in HPA system regulation assessed with repeated DEX/CRH tests is a potential biomarker that may predict clinical outcome at follow-up. There is consensus that the drug development process could be improved, once reliable biomarkers become available that help to allow a judgement regarding the efficacy of a novel drug candidate. The combined DEX/CRH test seems to be a promising candidate for such a biomarker.

Neuroendocrinological mechanisms of actions of antidepressant drugs

Noradrenaline or serotonin (5-HT) reuptake-inhibiting antidepressants such as reboxetine or citalopram acutely stimulate cortisol and adrenocorticotrophic hormone (ACTH) secretion in healthy volunteers, whereas mirtazapine acutely inhibits the ACTH and cortisol release, probably due to its antagonism at central 5-HT(2) and/or H(1) receptors. These differential effects of antidepressants on cortisol and ACTH secretion in healthy subjects after single administration are also reflected by their different time course in the down-regulation of hypothalamic-pituitary-adrenocortical (HPA) axis hyperactivity in depressed patients as assessed by serial dexamethasone (DEX)/corticotrophin-releasing hormone (CRH) tests: Reuptake-inhibiting antidepressants such as reboxetine gradually normalise HPA axis hyperactivity in depressed patients during several weeks of treatment via up-regulation of mineralocorticoid and glucocorticoid receptor function and by step-by-step restoration of the disturbed feedback control. By contrast, mirtazapine markedly reduces HPA axis activity in depressed patients within 1 week, but there is a partial re-enhancement of HPA hormone secretion after several weeks of therapy. In all studies performed to date, the short-term effects of daily treatment with antidepressants on the DEX/CRH test results are comparable in responders and nonresponders. Moreover, a reduction in HPA axis activity is not necessarily followed by a favourable clinical response and some depressed patients keep on showing nonsuppression in the DEX/CRH test despite clinical improvement. Therefore, the importance of HPA axis dysregulation for the short-term efficacy of antidepressants continues to be a matter of debate. However, there are convincing data suggesting that persisting nonsuppression in the DEX/CRH test despite clinical remission predicts an enhanced risk for relapse of depressive symptomatology with respect to the medium- and long-term outcome.

Time course of hypothalamic-pituitary-adrenocortical axis activity during treatment with reboxetine and mirtazapine in depressed patients

RATIONALE

In healthy subjects, cortisol and ACTH secretion are acutely stimulated by reboxetine and inhibited by mirtazapine. However, it was not investigated so far whether reboxetine and mirtazapine may also differ in their impact on hypothalamic-pituitary-adrenocortical (HPA) axis activity in depressed patients and whether these effects are related to clinical outcome.

OBJECTIVES

In the present study, we investigated the impact of 5-week treatment with reboxetine or mirtazapine on the combined dexamethasone suppression/corticotropin releasing hormone (DEX/CRH) test results in depressed patients.

METHODS

Forty drug-free patients suffering from a major depressive episode (Diagnostic and Statistical Manual of Mental Disorders-IV criteria) were treated with either reboxetine (8 mg/day; n=20) or mirtazapine (45 mg/day; n=20) for 5 weeks. Before, after 1 and 5 weeks of therapy, the DEX/CRH test was performed and cortisol and ACTH concentrations were measured.

RESULTS

During reboxetine treatment, a gradual and significant reduction in HPA axis activity as measured by the DEX/CRH test was seen, which was most pronounced after 5 weeks of treatment. In contrast, mirtazapine significantly reduced the cortisol and ACTH concentrations during the DEX/CRH test within 1 week. However, after 5 weeks of mirtazapine treatment, the cortisol and ACTH responses to the DEX/CRH test partially increased again both in responders and nonresponders.

CONCLUSIONS

This is the first study demonstrating differential effects of various antidepressants on the time course of serial DEX/CRH test results in depressed patients.

Assessment of the dexamethasone/CRH test as a state-dependent marker for hypothalamic-pituitary-adrenal (HPA) axis abnormalities in major depressive episode: a Multicenter Study

There is compelling evidence for the involvement of hypothalamic-pituitary-adrenal (HPA) axis abnormalities in depression. Growing evidence has suggested that the combined dexamethasone (DEX)/corticotropin-releasing hormone (CRH) test is highly sensitive to detect HPA axis abnormalities. We organized a multicenter study to assess the DEX/CRH test as a state-dependent marker for major depressive episode in the Japanese population. We conducted the DEX/CRH test in 61 inpatients with major depressive episode (Diagnostic and Statistical Manual of Mental Disorders 4th edition (DSM-IV)) and 57 healthy subjects. In all, 35 patients were repeatedly assessed with the DEX/CRH test on admission and before discharge. The possible relationships between clinical variables and the DEX/CRH test were also examined. Significantly enhanced pituitary-adrenocortical responses to the DEX/CRH test were observed in patients on admission compared with controls. Such abnormalities in patients were significantly reduced after treatment, particularly in those who underwent electroconvulsive therapy (ECT) in addition to pharmacotherapy. Age and female gender were associated with enhanced hormonal responses to the DEX/CRH test. Severity of depression correlated with DEX/CRH test results, although this was explained, at least in part, by a positive correlation between age and severity in our patients. Medication per se was unrelated to DEX/CRH test results. These results suggest that the DEX/CRH test is a sensitive state-dependent marker to monitor HPA axis abnormalities in major depressive episode during treatment. Restoration from HPA axis abnormalities occurred with clinical responses to treatment, particularly in depressed patients who underwent ECT.

The combined dexamethasone/CRH test as a potential surrogate marker in depression

There is compelling evidence that impaired corticosteroid receptor function is the key mechanism in the pathogenesis of depression resulting in a dysfunctional stress hormone regulation, which can be most sensitively detected with the combined dexamethasone (dex)/corticotropin releasing hormone (CRH) test. Treatment with different kinds of antidepressants is associated with a reduction of the hormonal responses to the combined dex/CRH test suggesting normalization of impaired corticosteroid receptor signaling as the final common pathway of these drugs. Consequently, the combined dex/CRH test is suggested as a screening tool to decide whether new compounds designed as antidepressants provide sufficient efficacy to normalize corticoid receptor signaling in depressed patients. We summarize own data and findings from the literature suggesting that (1) the neuroendocrine response to the combined dex/CRH test is elevated during a major depressive episode, but (2) tends to normalize after successful treatment. (3) Favorable response to antidepressant treatment can be predicted by determining the dex suppresser status on admission. For optimal prediction of non-response to antidepressant treatment, however, the results of a second dex/CRH test are necessary. These findings, together with the fact that impaired corticosteroid receptor signaling is considered as key mechanism of the pathogenesis in depression, support the suitability of the combined dex/CHR test as a surrogate marker for treatment response in depression. In conclusion, the combined dex/CRH test is a promising candidate to serve as a screening tool for the antidepressive effects of new compounds in clinical drug trials. Furthermore, the test appears to be capable of predicting the individual likelihood to respond to a current antidepressant treatment. If a drug treatment fails to normalize the outcome of the combined dex/CRH test, a change of the treatment strategy is recommended. Further systematic research is required and already ongoing to confirm the suitability of the combined dex/CRH test as a surrogate marker in depression.