Study protocol for the randomised controlled trial: antiglucocorticoid augmentation of anti-Depressants in Depression (The ADD Study)

The Role of Inflammatory Proteins in Anti-Glucocorticoid Therapy for Treatment-Resistant Depression

BACKGROUND

Optimising treatments for patients with treatment-resistant depression (TRD) is key to reducing the burden of this severe illness. The anti-glucocorticoid medication metyrapone has mixed evidence supporting a role as a possible augmentation treatment in TRD. The degree of treatment resistance in depression has been associated prospectively and retrospectively with elevated inflammation, and inflammatory activity may influence responses to antidepressant treatments.

AIMS

To investigate whether levels of pro-inflammatory cytokines are associated with clinical outcomes to metyrapone or placebo.

METHODS

A double-blind RCT randomised patients with TRD to 3 weeks of placebo or metyrapone augmentation to ongoing serotonergic antidepressants. No benefit of metyrapone was reported in the primary analysis. The current study assessed levels of pro-inflammatory proteins interleukin-6 (IL-6), tumour necrosis factor (TNFα), c-reactive protein (CRP) and interleukin-10 (IL-10) before randomisation and after treatment as potential moderators and/or mediators of clinical outcomes.

RESULTS

The three pro-inflammatory proteins (but not IL-10) were elevated in this sample of patients with TRD compared to a non-affected control group. High pre-treatment IL-6 levels predicted a poorer response in the trial overall but did not moderate response to metyrapone versus placebo. Changes in IL-6 indirectly mediated depression outcome, with metyrapone increasing IL-6 levels and IL-6 increase associated with a poorer outcome on depression. Other inflammatory proteins did not mediate or moderate treatment outcomes.

INTERPRETATION

Metyrapone is hypothesised to have a therapeutic effect in depression on the basis of inhibiting the synthesis of cortisol. In this study, metyrapone did not reduce cortisol, possibly due to glucocorticoid system overcompensation). The mediation effect of IL-6 may support this and perhaps help to indicate why the treatment was not effective.

Involvement of 5-HT-BDNF signaling axis in mediating synergistic antidepressant-like effects after combined administration of two oligosaccharide esters

Potential mechanisms of depression involving herbal medicines and their specific compounds include elevated 5-HT level and downstream BDNF pathway. To identify potentially new combined therapeutic strategies, 3,6'-disinapoylsucrose (DISS) and tenuifoliside A (TFSA) have been observed to show antidepressant-like effects and its related 5-HT-BDNF pathway. We have tried to investigate whether combined administration of DISS and TFSA exerted more effective in the treatment of depression, as assessed through tail suspension test (TST) and forced swimming test (FST). In addition, we also analyzed the expression of three important proteins, cyclic adenosine monophosphate (cAMP) response element binding (CREB), brain-derived neurotrophic factor (BDNF), and cAMP-regulated transcriptional coactivators (CRTC1), which have been shown to be involved in the regulation of the neurotrophic factors in the hippocampus. The DISS and TFSA separately, both at a dose of 5 mg/kg each, displayed small effect in the immobility time. However, combined treatment of these two in multiple doses exhibited better effect. Moreover, combined treatment of DISS and TFSA also demonstrated enhanced levels of 5-hydroxytryptamine (5-HT), and stronger increase in the phosphorylation levels of CREB, BDNF, and CRTC1 proteins in the hippocampus. Overall, our results indicated that coadministration of these two oligosaccharide esters at low dose may induce more pronounced antidepressant activity, in comparison with individual treatment even at high dosage. Thus, the antidepressant properties of both these compounds can be attributed to their ability to influence 5-HT and BDNF pathway, and thereby suggesting that this combination strategy can definitely act as alternative therapy for depression disorder with very limited side effects.

Antidepressant augmentation with metyrapone for treatment-resistant depression (the ADD study): a double-blind, randomised, placebo-controlled trial

BACKGROUND

Many patients with major depressive disorder have treatment-resistant depression, defined as no adequate response to two consecutive courses of antidepressants. Some evidence suggests that antiglucocorticoid augmentation of antidepressants might be efficacious in patients with major depressive disorder. We aimed to test the proof of concept of metyrapone for the augmentation of serotonergic antidepressants in the clinically relevant population of patients with treatment-resistant depression.

METHODS

This double-blind, randomised, placebo-controlled trial recruited patients from seven UK National Health Service (NHS) Mental Health Trusts from three areas (northeast England, northwest England, and the Leeds and Bradford area). Eligible patients were aged 18-65 years with treatment-resistant depression (Hamilton Depression Rating Scale 17-item score of ≥18 and a Massachusetts General Hospital Treatment-Resistant Depression staging score of 2-10) and taking a single-agent or combination antidepressant treatment that included a serotonergic drug. Patients were randomly assigned (1:1) through a centralised web-based system to metyrapone (500 mg twice daily) or placebo, in addition to their existing antidepressant regimen, for 21 days. Permuted block randomisation was done with a block size of two or four, stratified by centre and primary or secondary care setting. The primary outcome was improvement in Montgomery-Åsberg Depression Rating Scale (MADRS) score 5 weeks after randomisation, analysed in the modified intention-to-treat population of all randomly assigned patients that completed the MADRS assessment at week 5. The study has an International Standard Randomised Controlled Trial Number (ISRCTN45338259) and is registered with the EU Clinical Trial register, number 2009-015165-31.

FINDINGS

Between Feb 8, 2011, and Dec 10, 2012, 165 patients were recruited and randomly assigned (83 to metyrapone and 82 to placebo), with 143 (87%) completing the primary outcome assessment (69 [83%] in the metyrapone and 74 [90%] in the placebo group). At 5 weeks, MADRS score did not significantly differ between groups (21·7 points [95% CI 19·2-24·4] in the metyrapone group vs 22·6 points [20·1-24·8] in the placebo group; adjusted mean difference of -0·51 points [95% CI -3·48 to 2·46]; p=0·74). 12 serious adverse events were reported in four (5%) of 83 patients in the metyrapone group and six (7%) of 82 patients in the placebo group, none of which were related to study treatment. 134 adverse events occurred in 58 (70%) patients in the metyrapone group compared with 95 events in 45 (55%) patients in the placebo group, of which 11 (8%) events in the metyrapone group and four (4%) in the placebo group were judged by principle investigators at the time of occurrence to be probably related to the study drug.

INTERPRETATION

Metyrapone augmentation of antidepressants is not efficacious in a broadly representative population of patients with treatment-resistant depression within the NHS and therefore is not an option for patients with treatment-resistant depression in routine clinical practice at this time. Further research is needed to clarify if such augmentation might benefit subpopulations with demonstrable hypothalamic-pituitary-adrenal axis abnormalities.

FUNDING

Efficacy and Mechanism Evaluation (EME) programme, a UK Medical Research Council and National Institute for Health Research partnership.

Corticosterone mediates the synaptic and behavioral effects of chronic stress at rat hippocampal temporoammonic synapses

Chronic stress is thought to impart risk for depression via alterations in brain structure and function, but contributions of specific mediators in generating these changes remain unclear. We test the hypothesis that stress-induced increases in corticosterone (CORT), the primary rodent glucocorticoid, are the key mediator of stress-induced depressive-like behavioral changes and synaptic dysfunction in the rat hippocampus. In rats, we correlated changes in cognitive and affective behavioral tasks (spatial memory consolidation, anhedonia, and neohypophagia) with impaired excitatory strength at temporoammonic-CA1 (TA-CA1) synapses, an archetypical stress-sensitive excitatory synapse. We tested whether elevated CORT was sufficient and necessary to generate a depressive-like behavioral phenotype and decreased excitatory signaling observed at TA-CA1 after chronic unpredictable stress (CUS). Chronic CORT administration induced an anhedonia-like behavioral state and neohypophagic behavior. Like CUS, chronic, but not acute, CORT generated an impaired synaptic phenotype characterized by reduced α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-preferring glutamate receptor-mediated excitation at TA-CA1 synapses, decreased AMPA-type glutamate receptor subunit 1 protein expression, and altered serotonin-1B receptor-mediated potentiation. Repeatedly blunting stress-induced increases of CORT during CUS with the CORT synthesis inhibitor metyrapone (MET) prevented these stress-induced neurobehavioral changes. MET also prevented the CUS-induced impairment of spatial memory consolidation. We conclude that corticosterone is sufficient and necessary to mediate glutamatergic dysfunction underlying stress-induced synaptic and behavioral phenotypes. Our results indicate that chronic excessive glucocorticoids cause specific synaptic deficits in the hippocampus, a major center for cognitive and emotional processing, that accompany stress-induced behavioral dysfunction. Maintaining excitatory strength at stress-sensitive synapses at key loci throughout corticomesolimbic reward circuitry appears critical for maintaining normal cognitive and emotional behavior.

Evidence-based guidelines for treating depressive disorders with antidepressants: A revision of the 2008 British Association for Psychopharmacology guidelines

A revision of the 2008 British Association for Psychopharmacology evidence-based guidelines for treating depressive disorders with antidepressants was undertaken in order to incorporate new evidence and to update the recommendations where appropriate. A consensus meeting involving experts in depressive disorders and their management was held in September 2012. Key areas in treating depression were reviewed and the strength of evidence and clinical implications were considered. The guidelines were then revised after extensive feedback from participants and interested parties. A literature review is provided which identifies the quality of evidence upon which the recommendations are made. These guidelines cover the nature and detection of depressive disorders, acute treatment with antidepressant drugs, choice of drug versus alternative treatment, practical issues in prescribing and management, next-step treatment, relapse prevention, treatment of relapse and stopping treatment. Significant changes since the last guidelines were published in 2008 include the availability of new antidepressant treatment options, improved evidence supporting certain augmentation strategies (drug and non-drug), management of potential long-term side effects, updated guidance for prescribing in elderly and adolescent populations and updated guidance for optimal prescribing. Suggestions for future research priorities are also made.

HPA axis and aging in depression: systematic review and meta-analysis

One of the most consistent findings in the biology of depression is an altered activity of the hypothalamic-pituitary-adrenal (HPA) axis. However, data concerning this issue have never been examined with a focus on the older population. Here we present a systematic review and meta-analysis, based on studies investigating levels of cortisol, adrenocorticotropic hormone (ACTH) and corticotropin-releasing hormone (CRH) in depressed participants older than 60 and compared with healthy controls. We found 20 studies, for a total of 43 comparisons on different indices of HPA axis functioning. Depression had a significant effect (Hedges' g) on basal cortisol levels measured in the morning (0.89), afternoon (0.83) and night (1.39), but a smaller effect on cortisol measured continuously (0.51). The effect of depression was even higher on post-dexamethasone cortisol levels (3.22), whereas it was non-significant on morning ACTH and CRH levels. Subgroup analyses indicated that various methodological and clinical factors can influence the study results. Overall, older participants suffering from depression show a high degree of dysregulation of HPA axis activity, with differences compared with younger adults. This might depend on several mechanisms, including physical illnesses, alterations in the CNS and immune-endocrinological alterations. Further studies are needed to clarify the implications of altered HPA axis activity in older patients suffering from depression. Novel pharmacological approaches might be effective in targeting this pathophysiological feature, thus improving the clinical outcomes.