Efficacy and safety of triiodothyronine supplementation in patients with major depressive disorder treated with specific serotonin reuptake inhibitors

Effects of selective serotonin reuptake inhibitors on endocrine system (Review)

Selective serotonin reuptake inhibitors (SSRIs) are typically prescribed for treating major depressive disorder (MDD) due to their high efficacy. These drugs function by inhibiting the reuptake of serotonin [also termed 5-hydroxytryptamine (5-HT)], which raises the levels of 5-HT in the synaptic cleft, leading to prolonged activation of postsynaptic 5-HT receptors. Despite the therapeutic benefits of SSRIs, this mechanism of action also disturbs the neuroendocrine response. Hypothalamic-pituitary-adrenal (HPA) axis activity is strongly linked to both MDD and the response to antidepressants, owing to the intricate interplay within the serotonergic system, which regulates feeding, water intake, sexual drive, reproduction and circadian rhythms. The aim of the present review was to provide up-to-date evidence for the proposed effects of SSRIs, such as fluoxetine, citalopram, escitalopram, paroxetine, sertraline and fluvoxamine, on the endocrine system. For this purpose, the literature related to the effects of SSRIs on the endocrine system was searched using the PubMed database. According to the available literature, SSRIs may have an adverse effect on glucose metabolism, sexual function and fertility by dysregulating the function of the HPA axis, pancreas and gonads. Therefore, considering that SSRIs are often prescribed for extended periods, it is crucial to monitor the patient closely with particular attention to the function of the endocrine system.

Treatment-Resistant Depression in Older Adults

A 67-year-old woman with a history of obesity, chronic low back pain, and recurrent episodes of major depression presents with mild depressive symptoms of more than 2 years’ duration, with worsening symptoms over the past 4 months. She was receiving sertraline at a stable dose of 100 mg per day until 3 months ago, when she initially presented for her worsening depressive symptoms. At that time, sertraline was tapered off, and treatment with extra-long extended-release bupropion (bupropion XL) was started at a dose of 150 mg daily and was increased to 300 mg daily 3 weeks later. Despite having taken the higher dose of bupropion XL for more than 2 months, the patient continues to have low mood, loss of interest in usual pleasurable activities, trouble falling asleep, wakefulness several times during the night, diminished energy, poor appetite, difficulty concentrating, and intrusive thoughts of being “better off dead,” but she does not have active suicidal thinking. Her nine-question Patient Health Questionnaire (PHQ-9) score is 17 (on a scale of 0 to 27, with higher scores indicating greater severity of depressive symptoms). How would you evaluate and treat this patient?

Triiodothyronine Treatment reverses Depression-Like Behavior in a triple-transgenic animal model of Alzheimer's Disease

Alzheimer disease's (AD) is a neurodegenerative disorder characterized by cognitive and behavioral impairment. The central nervous system is an important target of thyroid hormones (TH). An inverse association between serum triiodothyronine (T3) levels and the risk of AD symptoms and progression has been reported. We investigated the effects of T3 treatment on the depression-like behavior in male transgenic 3xTg-AD mice. Animals were divided into 2 groups treated with daily intraperitoneal injections of 20 ng/g of body weight (b.w.) L-T3 (T3 group) or saline (vehicle, control group). The experimental protocol lasted 21 days, and behavioral tests were conducted on days 18-20. At the end of the experiment, the TH profile and hippocampal gene expression were evaluated. The T3-treated group significantly increased serum T3 and decreased thyroxine (T4) levels. When compared to control hippocampal samples, the T3 group exhibited attenuated glycogen synthase kinase-3 (GSK3), metalloproteinase 10 (ADAM10), amyloid-beta precursor-protein (APP), serotonin transporter (SERT), 5HT1A receptor, monocarboxylate transporter 8 (MCT8) and bone morphogenetic protein 7 (BMP-7) gene expression, whereas augmented superoxide dismutase 2 (SOD2) and Hairless gene expression. T3-treated animals also displayed reduced immobility time in both the tail suspension and forced swim tests, and in the latter presented a higher latency time compared to the control group. Therefore, our findings suggest that in an AD mouse model, T3 supplementation promotes improvements in depression-like behavior, through the modulation of the serotonergic related genes involved in the transmission mediated by 5HT1A receptors and serotonin reuptake, and attenuated disease progression.

Key considerations in the pharmacological management of treatment-resistant depression

Introduction: Treatment-resistant depression (TRD) is a complex, multifactorial, and biologically heterogeneous disorder with debilitating outcomes. Understanding individual reasons why patients do not respond to treatment is necessary for improving clinical recommendations regarding medication regimens, augmentation strategies, and alternative treatments.Areas covered: This manuscript reviews evidence-based treatment strategies for the clinical management of TRD. Current developments in the field and potential future recommendations for personalized treatment of TRD are also discussed.Expert opinion: Treatment guidelines for TRD are limited by the heterogeneous nature of the disorder. Furthermore, current strategies reflect this heterogeneity by emphasizing disease characteristics as well as drug trial response or failure. Developing robust biomarkers that could one day be integrated into clinical practice has the potential to advance specific treatment targets and ultimately improve treatment and remission outcomes.

Pharmacological Augmentation in Unipolar Depression: A Guide to the Guidelines

BACKGROUND

Pharmacological augmentation is a recommended strategy for patients with treatment-resistant depression. A range of guidelines provide advice on treatment selection, prescription, monitoring and discontinuation, but variation in the content and quality of guidelines may limit the provision of objective, evidence-based care. This is of importance given the side effect burden and poorer long-term outcomes associated with polypharmacy and treatment-resistant depression. This review provides a definitive overview of pharmacological augmentation recommendations by assessing the quality of guidelines for depression and comparing the recommendations made.

METHODS

A systematic literature search identified current treatment guidelines for depression published in English. Guidelines were quality assessed using the Appraisal of Guidelines for Research and Evaluation II tool. Data relating to the prescription of pharmacological augmenters were extracted from those developed with sufficient rigor, and the included recommendations compared.

RESULTS

Total of 1696 records were identified, 19 guidelines were assessed for quality, and 10 were included. Guidelines differed in their quality, the stage at which augmentation was recommended, the agents included, and the evidence base cited. Lithium and atypical antipsychotics were recommended by all 10, though the specific advice was not consistent. Of the 15 augmenters identified, no others were universally recommended.

CONCLUSIONS

This review provides a comprehensive overview of current pharmacological augmentation recommendations for major depression and will support clinicians in selecting appropriate treatment guidance. Although some variation can be accounted for by date of guideline publication, and limited evidence from clinical trials, there is a clear need for greater consistency across guidelines to ensure patients receive consistent evidence-based care.

The identification, assessment and management of difficult-to-treat depression: An international consensus statement

BACKGROUND

Many depressed patients are not able to achieve or sustain symptom remission despite serial treatment trials - often termed "treatment resistant depression". A broader, perhaps more empathic concept of "difficult-to-treat depression" (DTD) was considered.

METHODS

A consensus group discussed the definition, clinical recognition, assessment and management implications of the DTD heuristic.

RESULTS

The group proposed that DTD be defined as "depression that continues to cause significant burden despite usual treatment efforts". All depression management should include a thorough initial assessment. When DTD is recognized, a regular reassessment that employs a multi-dimensional framework to identify addressable barriers to successful treatment (including patient-, illness- and treatment-related factors) is advised, along with specific recommendations for addressing these factors. The emphasis of treatment, in the first instance, shifts from a goal of remission to optimal symptom control, daily psychosocial functional and quality of life, based on a patient-centred approach with shared decision-making to enhance the timely consideration of all treatment options (including pharmacotherapy, psychotherapy, neurostimulation, etc.) to optimize outcomes when sustained remission is elusive.

LIMITATIONS

The recommended definition and management of DTD is based largely on expert consensus. While DTD would seem to have clinical utility, its specificity and objectivity may be insufficient to define clinical populations for regulatory trial purposes, though DTD could define populations for service provision or phase 4 trials.

CONCLUSIONS

DTD provides a clinically useful conceptualization that implies a search for and remediation of specific patient-, illness- and treatment obstacles to optimizing outcomes of relevance to patients.

Depression

Major depression is a common illness that severely limits psychosocial functioning and diminishes quality of life. In 2008, WHO ranked major depression as the third cause of burden of disease worldwide and projected that the disease will rank first by 2030.¹ In practice, its detection, diagnosis, and management often pose challenges for clinicians because of its various presentations, unpredictable course and prognosis, and variable response to treatment.

Expression levels of interferon-ɣ and type 2 deiodinase in patients diagnosed with recurrent depressive disorders

BACKGROUND

Thyroid hormones (TH) are involved in modulation of the immune system and inflammation. TH dysregulation is associated with depressive disorders. The iodothyronine deiodinases (DIOs), the key enzymes for TH synthesis, can be affected and induced by pro-inflammatory cytokines. We aimed to investigate the levels of and correlation between type 2 DIO (DIO2) and interferon-gamma (IFN-ɣ) in patients with recurrent depressive disorders (rDD).

METHODS

Data from 91 rDD patients and 105 healthy controls were analyzed. The diagnoses are based on the ICD-10 criteria (F33.0-F33.8). Expression levels of DIO2 and IFN-ɣ were estimated using the method based on the polymerase chain reaction and the enzyme-linked immunosorbent assay (ELISA).

RESULTS

The DIO2 expression on mRNA/protein levels in rDD patients (both female and males) was reduced as compared with the control subjects. No correlation between DIO2 and IFN-ɣ expression was observed.

CONCLUSION

This is the first study to reveal that one may cautiously suggest that DIO2 may be involved in the development and/or progression of rDD. The mechanisms of TH regulation on depression, however, need further investigation.

Investigational drugs in recent clinical trials for treatment-resistant depression

INTRODUCTION

The authors describe the medications for treatment-resistant depression (TRD) in phase II/III of clinical development in the EU and USA and provide an opinion on how current treatment can be improved in the near future. Areas covered: Sixty-two trials were identified in US and EU clinical trial registries that included six investigational compounds in recent phase III development and 12 others in recent phase II clinical trials. Glutamatergic agents have been the focus of many studies. A single intravenous dose of the glutamatergic modulator ketamine produces a robust and rapid antidepressant effect in persons with TRD; this effect continues to remain significant for 1 week. This observation was a turning point that opened the way for other, more selective glutamatergic modulators (intranasal esketamine, AVP-786, AVP-923, AV-101, and rapastinel). Of the remaining compounds, monoclonal antibodies open highly innovative therapeutic options, based on new pathophysiological approaches to depression. Expert commentary: Promising new agents are emerging for TRD treatment. Glutamatergic modulators likely represent a very promising alternative to monoaminergic antidepressant monotherapy. We could see the arrival of the first robust and rapid acting antidepressant drug in the near future, which would strongly facilitate the ultimate goal of recovery in persons with TRD.

Canadian Network for Mood and Anxiety Treatments (CANMAT) 2016 Clinical Guidelines for the Management of Adults with Major Depressive Disorder: Section 3. Pharmacological Treatments

BACKGROUND

The Canadian Network for Mood and Anxiety Treatments (CANMAT) conducted a revision of the 2009 guidelines by updating the evidence and recommendations. The scope of the 2016 guidelines remains the management of major depressive disorder (MDD) in adults, with a target audience of psychiatrists and other mental health professionals.

METHODS

Using the question-answer format, we conducted a systematic literature search focusing on systematic reviews and meta-analyses. Evidence was graded using CANMAT-defined criteria for level of evidence. Recommendations for lines of treatment were based on the quality of evidence and clinical expert consensus. "Pharmacological Treatments" is the third of six sections of the 2016 guidelines. With little new information on older medications, treatment recommendations focus on second-generation antidepressants.

RESULTS

Evidence-informed responses are given for 21 questions under 4 broad categories: 1) principles of pharmacological management, including individualized assessment of patient and medication factors for antidepressant selection, regular and frequent monitoring, and assessing clinical and functional outcomes with measurement-based care; 2) comparative aspects of antidepressant medications based on efficacy, tolerability, and safety, including summaries of newly approved drugs since 2009; 3) practical approaches to pharmacological management, including drug-drug interactions and maintenance recommendations; and 4) managing inadequate response and treatment resistance, with a focus on switching antidepressants, applying adjunctive treatments, and new and emerging agents.

CONCLUSIONS

Evidence-based pharmacological treatments are available for first-line treatment of MDD and for management of inadequate response. However, given the limitations of the evidence base, pharmacological management of MDD still depends on tailoring treatments to the patient.

Challenging Treatment-Resistant Major Depressive Disorder: A Roadmap for Improved Therapeutics

Major depressive disorder (MDD) is associated with a significant burden and costs to the society. As remission of depressive symptoms is achieved in only one-third of the MDD patients after the first antidepressant trial, unsuccessful treatments contribute largely to the observed suffering and social costs of MDD. The present article provides a summary of the therapeutic strategies that have been tested for treatment-resistant depression (TRD). A computerized search on MedLine/PubMed database from 1975 to September 2014 was performed, using the keywords “treatment-resistant depression”, “major depressive disorder”, “adjunctive”, “refractory” and “augmentation”. From the 581 articles retrieved, two authors selected 79 papers. A manual searching further considered relevant articles of the reference lists. The evidence found supports adding or switching to another antidepressant from a different class is an effective strategy in more severe MDD after failure to an initial antidepressant trial. Also, in subjects resistant to two or more classes of antidepressants, some augmentation strategies and antidepressant combinations should be considered, although the overall response and remission rates are relatively low, except for fast acting glutamatergic modulators. The wide range of available treatments for TRD reflects the complexity of MDD, which does not underlie diverse key features of the disorder. Larger and well-designed studies applying dimensional approaches to measure efficacy and effectiveness are warranted.

Depression

PURPOSE OF REVIEW

Depression is a presenting symptom of common psychiatric disorders such as major depressive disorder, bipolar disorder, and schizophrenia. Depression can also be the presenting symptom of several neurodegenerative disorders, including Alzheimer disease, dementia with Lewy bodies, frontotemporal dementia, and Parkinson disease. Depression can also cause cognitive impairment and is a risk factor for dementia. As a result of the intimate relationship between depression and dementia, differentiating between a psychiatric and a neurologic cause of depression and dementia can sometimes be very difficult. The purpose of this review is to discuss the diagnosis and treatment of depression and to demonstrate how new diagnostic tools are helping to identify the differential diagnosis of depression.

RECENT FINDINGS

It is a time of great advancement in the management of depression. Innovative new medications, psychotherapeutic modalities, and new and investigational somatic treatments (eg, transcranial magnetic stimulation, deep brain stimulation) are making it possible to ameliorate and manage symptoms more effectively in more patients.

SUMMARY

With our greater ability to improve the lives of patients with depression, it is important for neurologists to recognize depression and work with our psychiatric colleagues to help patients access the newest and best treatments.

Royal Australian and New Zealand College of Psychiatrists clinical practice guidelines for mood disorders

OBJECTIVES

To provide guidance for the management of mood disorders, based on scientific evidence supplemented by expert clinical consensus and formulate recommendations to maximise clinical salience and utility.

METHODS

Articles and information sourced from search engines including PubMed and EMBASE, MEDLINE, PsycINFO and Google Scholar were supplemented by literature known to the mood disorders committee (MDC) (e.g., books, book chapters and government reports) and from published depression and bipolar disorder guidelines. Information was reviewed and discussed by members of the MDC and findings were then formulated into consensus-based recommendations and clinical guidance. The guidelines were subjected to rigorous successive consultation and external review involving: expert and clinical advisors, the public, key stakeholders, professional bodies and specialist groups with interest in mood disorders.

RESULTS

The Royal Australian and New Zealand College of Psychiatrists clinical practice guidelines for mood disorders (Mood Disorders CPG) provide up-to-date guidance and advice regarding the management of mood disorders that is informed by evidence and clinical experience. The Mood Disorders CPG is intended for clinical use by psychiatrists, psychologists, physicians and others with an interest in mental health care.

CONCLUSIONS

The Mood Disorder CPG is the first Clinical Practice Guideline to address both depressive and bipolar disorders. It provides up-to-date recommendations and guidance within an evidence-based framework, supplemented by expert clinical consensus.

MOOD DISORDERS COMMITTEE

Professor Gin Malhi (Chair), Professor Darryl Bassett, Professor Philip Boyce, Professor Richard Bryant, Professor Paul Fitzgerald, Dr Kristina Fritz, Professor Malcolm Hopwood, Dr Bill Lyndon, Professor Roger Mulder, Professor Greg Murray, Professor Richard Porter and Associate Professor Ajeet Singh.

INTERNATIONAL EXPERT ADVISORS

Professor Carlo Altamura, Dr Francesco Colom, Professor Mark George, Professor Guy Goodwin, Professor Roger McIntyre, Dr Roger Ng, Professor John O'Brien, Professor Harold Sackeim, Professor Jan Scott, Dr Nobuhiro Sugiyama, Professor Eduard Vieta, Professor Lakshmi Yatham.

AUSTRALIAN AND NEW ZEALAND EXPERT ADVISORS

Professor Marie-Paule Austin, Professor Michael Berk, Dr Yulisha Byrow, Professor Helen Christensen, Dr Nick De Felice, A/Professor Seetal Dodd, A/Professor Megan Galbally, Dr Josh Geffen, Professor Philip Hazell, A/Professor David Horgan, A/Professor Felice Jacka, Professor Gordon Johnson, Professor Anthony Jorm, Dr Jon-Paul Khoo, Professor Jayashri Kulkarni, Dr Cameron Lacey, Dr Noeline Latt, Professor Florence Levy, A/Professor Andrew Lewis, Professor Colleen Loo, Dr Thomas Mayze, Dr Linton Meagher, Professor Philip Mitchell, Professor Daniel O'Connor, Dr Nick O'Connor, Dr Tim Outhred, Dr Mark Rowe, Dr Narelle Shadbolt, Dr Martien Snellen, Professor John Tiller, Dr Bill Watkins, Dr Raymond Wu.

The role of reproductive hormones in postpartum depression

Despite decades of research aimed at identifying the causes of postpartum depression (PPD), PPD remains common, and the causes are poorly understood. Many have attributed the onset of PPD to the rapid perinatal change in reproductive hormones. Although a number of human and nonhuman animal studies support the role of reproductive hormones in PPD, several studies have failed to detect an association between hormone concentrations and PPD. The purpose of this review is to examine the hypothesis that fluctuations in reproductive hormone levels during pregnancy and the postpartum period trigger PPD in susceptible women. We discuss and integrate the literature on animal models of PPD and human studies of reproductive hormones and PPD. We also discuss alternative biological models of PPD to demonstrate the potential for multiple PPD phenotypes and to describe the complex interplay of changing reproductive hormones and alterations in thyroid function, immune function, hypothalamic-pituitary-adrenal (HPA) axis function, lactogenic hormones, and genetic expression that may contribute to affective dysfunction. There are 3 primary lines of inquiry that have addressed the role of reproductive hormones in PPD: nonhuman animal studies, correlational studies of postpartum hormone levels and mood symptoms, and hormone manipulation studies. Reproductive hormones influence virtually every biological system implicated in PPD, and a subgroup of women seem to be particularly sensitive to the effects of perinatal changes in hormone levels. We propose that these women constitute a "hormone-sensitive" PPD phenotype, which should be studied independent of other PPD phenotypes to identify underlying pathophysiology and develop novel treatment targets.

Pharmacological treatment approaches to difficult-to-treat depression

In the Sequenced Treatment Alternatives to Relieve Depression (STAR*D) trial of almost 3000 patients with depression in the United States, 50% responded to the initial trial of a selective serotonin reuptake inhibitor antidepressant, but only a third achieved remission (nil or minimal depressive symptoms). The final remission rate, even after four potential treatment steps, was only 70%. This finding reflects the reality of clinical practice and highlights the need to employ the best available evidence in the management of people with complex depression. Before adopting a pharmacological strategy for a patient with difficult-to-treat depression, general clinical issues (such as missed psychiatric diagnoses, unresolved psychological issues and treatment non-adherence) should be considered. While there is no strong evidence for the order of implementing evidence-based pharmacological strategies for difficult-to-treat depression, we recommend: i) increase antidepressant dose; ii) switch to different antidepressant; iii) augment with a non-antidepressant agent; and iv) combine antidepressants. Sometimes it may be more appropriate to consider augmentation before switching antidepressants. The use of psychological interventions or other physical treatments such as electroconvulsive therapy should be considered at each step in management.

The integrative management of treatment-resistant depression: a comprehensive review and perspectives

BACKGROUND

Major depressive disorder is a prevalent and disabling illness. Notwithstanding numerous advances in the pharmacological treatment of depression, approximately 70% of patients do not remit after first-line antidepressant treatment.

METHODS

The MEDLINE/PubMed, EMBASE and ClinicalTrials.gov electronic databases were searched from inception to October 1, 2013, for randomized controlled trials (RCT), relevant open-label trials, meta-analyses and ongoing trials of pharmacological and psychotherapeutic approaches to treatment-resistant depression (TRD).

RESULTS

Switching to a different antidepressant is a useful option following nonresponse to a first-line agent. Although widely used in clinical practice, there is limited evidence to support antidepressant combination for TRD. Notwithstanding evidence for lithium or T3 augmentation to be successful in TRD, most studies were carried out when participants were treated with tricyclic antidepressants (TCA). Of the available strategies to augment the response to new-generation antidepressants, the use of some atypical antipsychotics is best supported by evidence. Several novel therapeutic options are currently discussed. Evidence suggests that cognitive therapy (CT) is an effective strategy for TRD.

CONCLUSIONS

The success of switching to a different antidepressant following a first-line agent is supported by evidence, but there is limited evidence for effective combination strategies. Lithium and T3 augmentation of TCA have the strongest evidence base for successful treatment of TRD. The use of augmentation of newer-generation antidepressants with atypical antipsychotics is supported by a growing evidence base. Current evidence supports CT as an effective strategy for TRD. There is a need for additional large-scale RCT of TRD. The development of new antidepressants targeting novel pathways opens a promising perspective for the management of TRD.

Guidelines for the treatment of hypothyroidism: prepared by the american thyroid association task force on thyroid hormone replacement

BACKGROUND

A number of recent advances in our understanding of thyroid physiology may shed light on why some patients feel unwell while taking levothyroxine monotherapy. The purpose of this task force was to review the goals of levothyroxine therapy, the optimal prescription of conventional levothyroxine therapy, the sources of dissatisfaction with levothyroxine therapy, the evidence on treatment alternatives, and the relevant knowledge gaps. We wished to determine whether there are sufficient new data generated by well-designed studies to provide reason to pursue such therapies and change the current standard of care. This document is intended to inform clinical decision-making on thyroid hormone replacement therapy; it is not a replacement for individualized clinical judgment.

METHODS

Task force members identified 24 questions relevant to the treatment of hypothyroidism. The clinical literature relating to each question was then reviewed. Clinical reviews were supplemented, when relevant, with related mechanistic and bench research literature reviews, performed by our team of translational scientists. Ethics reviews were provided, when relevant, by a bioethicist. The responses to questions were formatted, when possible, in the form of a formal clinical recommendation statement. When responses were not suitable for a formal clinical recommendation, a summary response statement without a formal clinical recommendation was developed. For clinical recommendations, the supporting evidence was appraised, and the strength of each clinical recommendation was assessed, using the American College of Physicians system. The final document was organized so that each topic is introduced with a question, followed by a formal clinical recommendation. Stakeholder input was received at a national meeting, with some subsequent refinement of the clinical questions addressed in the document. Consensus was achieved for all recommendations by the task force.

RESULTS

We reviewed the following therapeutic categories: (i) levothyroxine therapy, (ii) non-levothyroxine-based thyroid hormone therapies, and (iii) use of thyroid hormone analogs. The second category included thyroid extracts, synthetic combination therapy, triiodothyronine therapy, and compounded thyroid hormones.

CONCLUSIONS

We concluded that levothyroxine should remain the standard of care for treating hypothyroidism. We found no consistently strong evidence for the superiority of alternative preparations (e.g., levothyroxine-liothyronine combination therapy, or thyroid extract therapy, or others) over monotherapy with levothyroxine, in improving health outcomes. Some examples of future research needs include the development of superior biomarkers of euthyroidism to supplement thyrotropin measurements, mechanistic research on serum triiodothyronine levels (including effects of age and disease status, relationship with tissue concentrations, as well as potential therapeutic targeting), and long-term outcome clinical trials testing combination therapy or thyroid extracts (including subgroup effects). Additional research is also needed to develop thyroid hormone analogs with a favorable benefit to risk profile.

Faster, better, stronger: towards new antidepressant therapeutic strategies

Major depression is a highly prevalent disorder and is predicted to be the second leading cause of disease burden by 2020. Although many antidepressant drugs are currently available, they are far from optimal. Approximately 50% of patients do not respond to initial first line antidepressant treatment, while approximately one third fail to achieve remission following several pharmacological interventions. Furthermore, several weeks or months of treatment are often required before clinical improvement, if any, is reported. Moreover, most of the commonly used antidepressants have been primarily designed to increase synaptic availability of serotonin and/or noradrenaline and although they are of therapeutic benefit to many patients, it is clear that other therapeutic targets are required if we are going to improve the response and remission rates. It is clear that more effective, rapid-acting antidepressants with novel mechanisms of action are required. The purpose of this review is to outline the current strategies that are being taken in both preclinical and clinical settings for identifying superior antidepressant drugs. The realisation that ketamine has rapid antidepressant-like effects in treatment resistant patients has reenergised the field. Further, developing an understanding of the mechanisms underlying the rapid antidepressant effects in treatment-resistant patients by drugs such as ketamine may uncover novel therapeutic targets that can be exploited to meet the Olympian challenge of developing faster, better and stronger antidepressant drugs.

Hypothyroidism and depression

BACKGROUND

A relationship between hypothyroidism and depression has been assumed for many years; however, the true nature of this association has been difficult to define with many conflicting studies. In recent years, our knowledge in this area has increased significantly with large cohort studies and genetically driven studies being published.

OBJECTIVES

We reviewed the literature on thyroid function and depression to determine if this relationship has been clarified.

METHODS

We performed a search on the Pubmed database using the terms 'thyroid
 ' and 'mental health
 ', 'depression
 ' and 'well-being
 '.

RESULTS

Large epidemiological studies generally suggest no association between thyroid function and depression in subjects without thyroid disease. Subjects on thyroxine have poorer psychological well-being than subjects with no thyroid disease even if biochemically euthyroid, they also show an association between thyroid function and well-being. Whilst there is some early evidence that genetic factors can influence well-being on thyroxine and response to combination therapy, there is also evidence to suggest that much morbidity on thyroxine may be due to initial misdiagnosis and mis-attribution of symptoms.

CONCLUSION

Despite the large number of studies, the relationship between thyroid function and depression remains poorly defined. Clarification of the proportion of subjects on thyroxine incorrectly may assist the large (perhaps genetically driven) studies needed to move forward in this area, as it is expected that they cloud the results.

Neuropsychiatric manifestations of thyroid disease

The interface between thyroid hormone action and neuropsychiatric function is intricate, and several mechanisms of thyroid hormone uptake into brain tissues, hormone activation, and influences on neurotransmitter generation have been identified. Symptoms of hypothyroidism are nonspecific, whereas those attributed to thyrotoxicosis may be more characteristic. Neuropsychiatric manifestations triggered by thyroid dysfunction likely respond well to reestablishment of the euthyroid state, although some patients have persistent complaints. The addition of LT3 to ongoing LT4 replacement has yet to be definitively shown to be advantageous. Treatment of euthyroid depression with LT3 in addition to antidepressant therapy lacks convincing evidence of superior outcomes.

Evidence for the benefits of nonantipsychotic pharmacological augmentation in the treatment of depression

Failure to achieve an adequate response after initial antidepressant treatment in patients with depression is common and remains a clinical challenge. In recent years, some atypical antipsychotic agents have been approved by the US Food and Drug Administration for use in an augmentation strategy for major depressive disorder, and other agents are already in common use in clinical practice. We conducted a search of MEDLINE for relevant studies of augmentation strategies using randomized controlled trials and meta-analyses, and we summarize and discuss the various agents other than atypical antipsychotics. Lithium and thyroid hormone augmentation may improve the response of tricyclic antidepressants but not that of selective serotonin reuptake inhibitors. The efficacy of augmentation with modafinil, buspirone, methylphenidate, folic acid, pindolol and lamotrigine is limited or equivocal. Most of the studies have not focused on treatment-resistant depression (TRD). More trials are needed to help develop evidence-based options for augmentation in TRD.

Mechanism-based testing strategy using in vitro approaches for identification of thyroid hormone disrupting chemicals

The thyroid hormone (TH) system is involved in several important physiological processes, including regulation of energy metabolism, growth and differentiation, development and maintenance of brain function, thermo-regulation, osmo-regulation, and axis of regulation of other endocrine systems, sexual behaviour and fertility and cardiovascular function. Therefore, concern about TH disruption (THD) has resulted in strategies being developed to identify THD chemicals (THDCs). Information on potential of chemicals causing THD is typically derived from animal studies. For the majority of chemicals, however, this information is either limited or unavailable. It is also unlikely that animal experiments will be performed for all THD relevant chemicals in the near future for ethical, financial and practical reasons. In addition, typical animal experiments often do not provide information on the mechanism of action of THDC, making it harder to extrapolate results across species. Relevant effects may not be identified in animal studies when the effects are delayed, life stage specific, not assessed by the experimental paradigm (e.g., behaviour) or only occur when an organism has to adapt to environmental factors by modulating TH levels. Therefore, in vitro and in silico alternatives to identify THDC and quantify their potency are needed. THDC have many potential mechanisms of action, including altered hormone production, transport, metabolism, receptor activation and disruption of several feed-back mechanisms. In vitro assays are available for many of these endpoints, and the application of modern '-omics' technologies, applicable for in vivo studies can help to reveal relevant and possibly new endpoints for inclusion in a targeted THDC in vitro test battery. Within the framework of the ASAT initiative (Assuring Safety without Animal Testing), an international group consisting of experts in the areas of thyroid endocrinology, toxicology of endocrine disruption, neurotoxicology, high-throughput screening, computational biology, and regulatory affairs has reviewed the state of science for (1) known mechanisms for THD plus examples of THDC; (2) in vitro THD tests currently available or under development related to these mechanisms; and (3) in silico methods for estimating the blood levels of THDC. Based on this scientific review, the panel has recommended a battery of test methods to be able to classify chemicals as of less or high concern for further hazard and risk assessment for THD. In addition, research gaps and needs are identified to be able to optimize and validate the targeted THD in vitro test battery for a mechanism-based strategy for a decision to opt out or to proceed with further testing for THD.

The hidden third: improving outcome in treatment-resistant depression

Treatment-resistant depression (TRD) presents many challenges for both patients and physicians. This review aims to evaluate the current status of the field of TRD and reflects the main findings of a consensus meeting held in September 2009. Literature searches were also conducted using PubMed and EMBASE. Abstracts of the retrieved articles were reviewed independently by the authors for inclusion. Evaluation of the clinical evidence in TRD is complicated by the absence of a validated definition, and there is a need to move away from traditional definitions of remission based on severity of symptoms to one that includes normalisation of functioning. One potential way of improving treatment of TRD is through the use of predictive biomarkers and clinical variables. The advent of new treatments may also help by focusing on neurotransmitters other than serotonin. Strategies such as the switching of antidepressants, use of combination therapy with lithium, atypical antipsychotics and other pharmacological agents can improve outcomes, and techniques such as deep brain stimulation and vagus nerve stimulation have shown promising early results. Despite consistent advances in the pharmacotherapy of mood disorders in the last decade, high rates of TRD are still a challenging aspect of overall management.

Management of treatment-resistant depression

Given the limitations of evidence for treatment options that are consistently effective for TRD and the possibility that TRD is in fact a form of depression that has a low probability of resolving, how can clinicians help patients with TRD? Perhaps the most important conceptual shift that needs to take place before treatment can be helpful is to accept TRD as a chronic illness, an illness similar to many others, one that can be effectively managed but that is not, at our present level of knowledge, likely to be cured. An undue focus on remission or even a 50% diminution of symptoms sets unrealistic goals for both patients and therapists and may lead to overtreatment and demoralization. The focus should be less on eliminating depressive symptoms and more on making sense of and learning to function better in spite of them. It is important to acknowledge the difficult nature of the depressive illness, to remove blame from the patient and clinician for not achieving remission, to set realistic expectations, and to help promote better psychosocial functioning even in the face of persisting symptoms. The critical element when implementing such an approach is a judicious balance between maintaining hope for improvement without setting unrealistic expectations. It is important to reemphasize that following a disease management model with acceptance of the reality of a chronic illness is not nihilistic and does not mean the abandonment of hope for improvement. The first step in treating a patient with TRD is to perform a comprehensive assessment of the patient’s past and current treatment history to ensure that evidence-based treatment trials have in fact been undertaken, and if not, such treatment trials should be implemented. If the patient continues to have significant residual symptoms, it is important to determine the impact is of these symptoms on the patient’s quality of life and ability to function. It is also important to evaluate the factors that may be contributing to the persistence of depressive symptoms such as comorbid personality disorders, somatic disorders, substance abuse, and work and interpersonal conflicts. The treatment of patients with TRD needs to move beyond attempts to modify symptoms without taking into consideration and attempting to modify the patient’s personality, coping skills, and social system. Further somatic treatment trials can be undertaken, if desired by the patient and therapist, as a small (5%–15%) percentage of patients may respond and further treatment trials, and this may engender hope. The risk with this approach is that patients and therapists may not work at disease management skills if they believe there may be a resolution of the depression if they could just find the right medication or intervention. Therapists may also feel pressured by patients, families, insurance companies, as well as their own sense of helplessness to escalate treatment in a more and more aggressive manner in an attempt to achieve an elusive remission. A disease management program can provide the therapist and patient with sufficient structure, skills, and goals to encourage ongoing treatment without resorting to unproven measures that may create more side effects and problems. It is particularly important to include the patient’s significant others in the reformulation of the patient’s problem and thereby learn how to manage the illness more effectively. Significant others and family members can be invaluable in providing support for dealing with the difficult process of acquiring a new skill set. Indeed, they spend significantly more time with the patient than does any therapist. Family members are likely to provide this kind of support only if they have been part of the assessment and treatment process. Patients with a wide range of chronic medical illnesses can and do learn to function effectively and to achieve a satisfying quality of life in spite of their illness. There is no reason to think that patients with TRD should not be able to achieve a similar level of illness management, functioning, and quality of life.

Effect of triiodothyronine (T(3)) augmentation of acute milnacipran administration on monoamine levels: an in vivo microdialysis study in rats

BACKGROUND

Up to 30% of depressed patients are partially or totally resistant to antidepressant therapy. The administration of triiodothyronine (T(3)) to antidepressant nonresponders can be an effective augmentation strategy, although the mechanism is not fully understood.

METHODS

In vivo microdialysis was used to examine the effect of T(3) augmentation of the antidepressant, milnacipran. Basal extracellular serotonin, norepinephrine, and dopamine levels were measured before and after acute milnacipran administration in the medial prefrontal cortex and amygdala of rats which had received subchronic (7 days) T(3) treatment or control saline.

RESULTS

Subchronic administration of T(3) at 0.1 mg/kg significantly increased basal extracellular levels of serotonin in the medial prefrontal cortex, but not in the amygdala. In contrast, subchronic administration of T(3) at 0.2 mg/kg did not alter basal extracellular serotonin levels in the medial prefrontal cortex. Basal extracellular levels of norepinephrine and dopamine were not modified by either dose of T(3) in either region. Acute administration of milnacipran, a serotonin-norepinephrine reuptake inhibitor, to control animals resulted in a significant increase of extracellular levels of serotonin, norepinephrine, and dopamine. When administered to animals treated subchronically with T(3) at 0.1 mg/kg, milnacipran produced an additional increase in extracellular serotonin levels but not in levels of norepinephrine or dopamine in the medial prefrontal cortex of rats.

CONCLUSION

These results suggest that the mechanism of the augmentation effect of milnacipran by T(3) administration occurs via enhancement of serotonergic neurotransmission, but not through noradrenergic or dopaminergic neurotransmission.

Antidepressant augmentation and combination in unipolar depression: strong guidance, weak foundations

Depression will be the second leading contributor to the global burden of disease by 2020. In Ireland, in 2009, 6061 people were hospitalised with depressive disorders. This represents a significant economic and social burden. There is growing awareness of the difficulty in treating depression with medications alone. The likelihood that a patient will achieve remission with the first antidepressant tried is around 30%, and the rates are similar for the second antidepressant tried. This falls to around 15% after three trials. Many patients are exposed to pharmacotherapy for extended periods of time with little beneficial effect, but often with side-effects. Patients are therefore in great need of clear information with regard to their chance of success. Clinicians are in need of clear guidance on prescribing strategies which have proven efficacy. However, this guidance often discusses treatment strategies based on varying levels of evidence. Guiding bodies may approach the problem from varying perspectives. The UK National Institute for Health and Clinical Excellence (NICE) has a clear government mandate with regard to provision of not only effective but cost-effective treatments. The British Association of Psychopharmacology (BAP) is an independent body of interested researchers and therefore may discuss prescribing options from the point of view of tertiary care institutions, and university centres. The South London and Maudsley NHS Foundation Trust publish the popular Maudsley guidelines. These are perhaps more pragmatic in nature, but include very low levels of evidence, including case series. The American Psychiatric Association (APA) is an independent member association which also publishes guidelines. These are published in the American Journal of Psychiatry and the latest guidelines were published in October 2010. All these bodies attempt to weigh their advice according to the level of evidence available and aim to provide clinical guidance in difficult situations. The burden on guiding organisations is to provide some direction and clarity in areas that are often unclear or controversial. Clinical guidelines are one method of providing support and guidance to busy clinicians. However, this clinician-centered approach has limitations. The onus is on the authors of the guidance to provide ever-more treatment options. This may mean that conclusions about the efficacy of medications is overstated or the limitations of the literature not fully explored in explanatory notes.

[Therapeutic strategy of depressive episodes. Prevention of relapse risk]

Prevention of the risk of recurrence of depressive episodes is a dynamic process that begins early in the management. Although complete remission is obtained for almost half of the treated depressive episodes, a heuristic conceptual thinking apprehends depression as a potentially chronic disorder when considering relapse and recurrence prevention. Multiple actions of care have to be initiated. They are formalised, but also adjustable to the needs of a critical management period throughout the follow-up. These actions include the prescription of an antidepressant at an effective dosage. They also consider the preventative and therapeutic impact of psychotherapy. The search for residual symptoms of depression is the rule, and addition of other medication should be considered if needed. These recommendations are evidence-based in the context of recurrence prevention. Nevertheless, many other initiatives are equally important recommendations in terms of therapeutic impact. Thus, rigorous evaluation of the initial symptomatology, promotion of information on disease, health-care advices, as well as implementation of family and other networks are good-practices. Such actions should be conducted in a relationship based on a therapeutic alliance. These elements need to be adjusted and contextualised in line with the Health System, mode of medical practice and unique style of the therapist. Proactive and sustainable implementations of these guidelines are required in the context of a unique and open therapeutic relationship for both therapist and patient.

Hormone treatment of depression

There is a well-established relationship between alterations of various hormonal systems and psychiatric disorders, both in endocrine and psychiatric patients. This has led to clinical and research studies examining the efficacy of the different hormones for treatment of depression. These data will be reviewed with particular regard to the thyroid, gonadal, pineal, and adrenal cortex hormones. The data generally provide limited, but varying evidence for the antidepressant efficacy of these hormones.

If at first you don't succeed: a review of the evidence for antidepressant augmentation, combination and switching strategies

Major depressive disorder is a common and disabling illness that leads to significant reductions in quality of life and considerable cost to society. Despite numerous advances in the pharmacological treatment of depression, many patients remain ill despite initial treatment. Beyond first-line treatment, current guidelines recommend either augmentation or switching of the initial antidepressant. In this narrative review, we summarize the data from randomized controlled trials and meta-analyses in order to concisely discuss how the impact of current research can be translated into clinical practice and, ultimately, into lasting improvements in patient outcomes. The augmentation strategies reviewed are lithium, thyroid hormone, pindolol, psychostimulants and second-generation antipsychotics. The data on switching from first-line antidepressants to other antidepressants are also reviewed, and include switching within the same class, switching to other first-line antidepressant classes and switching to less commonly prescribed antidepressants. Finally, the strategy of antidepressant combinations is examined. Overall, the strength of evidence supporting a trial of augmentation or a switch to a new agent is very similar, with remission rates between 25% and 50% in both cases. Our review of the evidence suggests several conclusions. First, although it is true that adjunctive lithium and thyroid hormone have established efficacy, we can only be confident that this is true for use in combination with tricyclic antidepressants (TCAs), and the trials were done in less treatment-resistant patients than those who typically receive TCAs today. Of these two options, triiodothyronine augmentation seems to offer the best benefit/risk ratio for augmentation of modern antidepressants. After failure of a first-line selective serotonin reuptake inhibitor (SSRI), neither a switch within class nor a switch to a different class of antidepressant is unequivocally supported by the data, although switching from an SSRI to venlafaxine or mirtazapine may potentially offer greater benefits. Interestingly, switching from a newer antidepressant to a TCA after a poor response to the former is not supported by strong evidence. Of all strategies to augment response to new-generation antidepressants, quetiapine and aripiprazole are best supported by the evidence, although neither the cost effectiveness nor the longer-term benefit of these strategies has been established. The data to guide later steps in the treatment of resistant depression are sparse. Given the wide variety of options for the treatment of major depressive disorder, and the demonstrated importance of truly adequate treatment to the long-term outcomes of patients facing this illness, it is clear that further well conducted studies are needed.

Effect of triiodothyronine on antidepressant screening tests in mice and on presynaptic 5-HT1A receptors: mediation by thyroid hormone α receptors

Although triiodothyronine (T3) is widely used clinically, preclinical support for its antidepressant-like effects is limited, and the mechanisms are unknown. We evaluated 1) the antidepressant-like effects of T3 in the novelty suppressed feeding test (NSFT), tail suspension test (TST), and forced swim test (FST), 2) the role of presynaptic 5-HT(1A) receptors in the antidepressant-like mechanism of T3 by the hypothermic response to the 5-HT(1A) receptor agonist, 8-hydroxy-N,N-dipropyl-2-aminotetralin (8-OH-DPAT), 3) the thyroid hormone receptor type mediating the antidepressant-like effects by concurrent administration of the specific thyroid hormone α receptor (TRα) antagonist, dronedarone, and 4) the presence of these effects in both genders. Male and female BALB/c mice were administered 1) T3 (20, 50, 200, or 500 μg/kg per day) or vehicle or 2) T3 (50 μg/kg per day), dronedarone (100 μM/day), or the combination intraperitoneally for 21 days and then underwent a behavioral test battery. The NSFT showed a shortened latency to feed in males at the two lower T3 doses. The TST and FST showed decreased immobility in male mice at T3 doses >20 μg/kg per day and in females at all T3 doses. Concurrent dronedarone prevented T3 effects in males on the NSFT and in the TST and FST in both genders. Attenuation of 8-OH-DPAT-induced hypothermia was observed in males only and may be reduced by concurrent dronedarone. These findings support an antidepressant-like effect of T3. Attenuation of 8-OH-DPAT-induced hypothermia in males only suggests the need to evaluate a possible gender disparity in the role of presynaptic 5-HT(1A) receptors in T3 antidepressant mechanisms. Blockade by dronedarone of the antidepressant-like effects of T3 suggests that these effects are TRα receptor-mediated.

Targeting remission by 8 weeks: when should supplementation be considered in patients with major depression treated with a specific serotonin reuptake inhibitor?

BACKGROUND

Timely administration/supplementation of a specific serotonin reuptake inhibitor with a second therapeutic agent could improve treatment outcome in patients with major depressive disorder (MDD). The purpose of this study was to identify the optimal time at which to implement supplementation so as to maximize the likelihood of remission by 8 weeks and minimize overtreatment.

METHOD

Data from patients with MDD treated with sertraline (n = 108) or citalopram (n = 107) in a randomized controlled trial were analyzed by multivariate logistic regression. The 21-item Hamilton Depression Scale scores at weeks 1, 2, 3, 4, and 6; sex; age; and baseline Hamilton Anxiety Scale score were used as predictors of remission by 8 weeks sustained for a further 4 weeks.

RESULTS

Regression models for weeks 2, 3, 4, and 6 were significant (area under the curve values, 0.73-0.91). The models for weeks 3 to 6 yielded κ coefficients greater than 0.40 with the outcome variable. A Hamilton Depression Scale reduction score of 50% at week 4 as a criterion for supplementation would have resulted in overtreatment of 4% and 0% of patients in the sertraline and citalopram groups, respectively, and none if applied at week 6. The rates at which patients who should have received supplementation (destined to be nonremitters at 8 weeks) would have been missed would be 49%/54% for sertraline/citalopram at week 4 and 43%/50% at week 6.

LIMITATIONS

The study limitations are as follows: secondary analysis of data, relatively low sertraline dose, and relatively small sample sizes.

CONCLUSIONS

It may be possible to identify patients treated with specific serotonin reuptake inhibitors who will not achieve sustained remission by 8 weeks. If supplementation were implemented accordingly, the number of overtreated patients would be small. However, a substantial number of patients who should be supplemented would be missed, indicating a need for greater sensitivity of the prediction model. Further studies are needed.

The thyroid hormone, triiodothyronine, enhances fluoxetine-induced neurogenesis in rats: possible role in antidepressant-augmenting properties

The thyroid hormone triiodothyronine (T3) may accelerate and augment the action of antidepressants. Antidepressants up-regulate neurogenesis in adult rodent hippocampus. We studied the effect of T3 and T3+fluoxetine in enhancement of hippocampal neurogenesis beyond that induced by fluoxetine alone and the correlation with antidepressant behaviour in the novelty suppressed feeding test (NSFT). Rats were administered fluoxetine (5 mg/kg.d), T3 (50 mug/kg.d), fluoxetine (5 mg/kg.d)+T3 (50 mug/kg.d) or saline, for 21 d. Neurogenesis was studied by doublecortin (DCX) immunohistochemistry in the subgranular zone (SGZ) of the hippocampus and the subventricular zone (SVZ). In the NSFT, latency to feeding in animals deprived of food was measured. Fluoxetine and fluoxetine+T3 increased the number of doublecortin-positive (DCX+) cells in the SGZ compared to saline (p=0.00005, p=0.008, respectively). There was a trend towards an increased number of DCX+ cells by T3 compared to saline (p=0.06). Combined treatment with fluoxetine+T3 further increased the number of DCX+ cells compared to T3 or fluoxetine alone (p=0.001, p=0.014, respectively). There was no effect of any of the treatments on number of DCX+ cells in the SVZ. In the NSFT, all treatments (T3, fluoxetine+T3 and fluoxetine) reduced latency to feeding compared to saline (p=0.0004, p=0.00001, p=0.00009, respectively). Fluoxetine+T3 further reduced latency to feeding compared to T3 alone (p=0.05). The results suggest that enhancement of antidepressant action by T3 may be related to its effect of increasing hippocampal neurogenesis and that the antidepressant effect of these treatments is specific to the hippocampus and does not represent a general effect on cell proliferation.

Effect of triiodothyronine on 5-HT1A and 5-HT1B receptor expression in rat forebrain and on latency to feed in the novelty suppressed feeding test

Thyroid hormones, particularly triiodothyronine (T3), have long been used for the treatment of depression, most frequently to enhance the therapeutic activity of other antidepressants. The purpose of this study was to evaluate possible underlying mechanisms for the antidepressant activity of T3. The effects of T3 20 microg/kg/d S.C. and fluoxetine 5mg/kg/d I.P. given alone or in combination for 7 days on the transcription rates of inhibitory serotonergic receptors (5-HT1A and 5-HT1B) were studied in different brain areas of male Sabra rats using real-time PCR. Significant effects of fluoxetine were found on the expression of 5-HT1B receptors in the frontal cortex and of T3 on the expression of 5-HT1A receptors in the amygdala and hippocampus and 5-HT1B receptors in the frontal and entorhinal cortices, the expression being reduced in all cases. An effect of the combination of T3 plus fluoxetine to reduce transcription was observed for 5-HT1A receptors, in the amygdala and dentate gyrus and for 5-HT1B receptors in the entorhinal cortex and anterior raphe nucleus. In the second experiment, the novelty suppressed feeding test (NFST) was used to examine the effects of fluoxetine 5mg/kg/d I.P. and T3 20 or 50 microg/kg/d, alone or in combination for 12 days, on latency to feed. Only the combinations of T3 (20 or 50 microg/kg/d) and fluoxetine (5mg/kg/d) yielded significant behavioral effects in this test. The results of our studies suggest that the mechanism underlying the antidepressant effect of T3 may involve a reduction in 5-HT1A and 5-HT1B receptor transcription rates.

In the clinic. Depression

This issue provides a clinical overview of depression focusing on prevention, diagnosis, treatment, practice improvement, and patient information. Readers can complete the accompanying CME quiz for 1.5 credits. Only ACP members and individual subscribers can access the electronic features of In the Clinic. Non-subscribers who wish to access this issue of In the Clinic can elect "Pay for View." Subscribers can receive 1.5 category 1 CME credits by completing the CME quiz that accompanies this issue of In the Clinic. The content of In the Clinic is drawn from the clinical information and education resources of the American College of Physicians (ACP), including PIER (Physicians' Information and Education Resource) and MKSAP (Medical Knowledge and Self Assessment Program). Annals of Internal Medicine editors develop In the Clinic from these primary sources in collaboration with the ACP's Medical Education and Publishing division and with assistance of science writers and physician writers. Editorial consultants from PIER and MKSAP provide expert review of the content. Readers who are interested in these primary resources for more detail can consult www.acponline.org, http://pier.acponline.org, and other resources referenced within each issue of In the Clinic.

Accelerating response to antidepressant treatment in depression: a review and clinical suggestions

OBJECTIVE

The primary objective of this article is to review the literature regarding the speed of response to antidepressant drugs and potential strategies to accelerate the antidepressant response in new antidepressant-free patients with depression. Based on these data, we try to propose both an effective and safe antidepressant treatment strategy to alleviate depressive symptoms at the earliest opportunity.

DATA SOURCES

Data were identified by searches of Medline (1966 to September 2009) and references from relevant articles and books. Search terms included depression, antidepressant, predictor, response, onset, acceleration, and augmentation. As our focus was on the acute phase treatment of depression, articles relevant to treatment-resistant depression were excluded. Only articles written in English or Japanese were consulted.

DATA SELECTION

Studies, reviews, and books pertaining to the treatment of depression with a special regard to accelerating therapeutic effects were selected.

DATA SYNTHESIS

Most of the available treatment guidelines for major depressive disorders recommend the continuous use of antidepressants for 4 to 8 weeks based on the idea of a delayed onset of response to these drugs. Contrary to this conventional belief, the recent data indicate that antidepressants start to exert their effects within 2 weeks and early non-response could predict a subsequent unfavorable outcome.

CONCLUSIONS

These findings suggest the need of revisiting the timing of an antidepressant switch for early non-responders, whereby switching could be commenced in as early as 2 weeks.

Therapeutic options for treatment-resistant depression

Treatment-resistant depression (TRD) presents major challenges for both patients and clinicians. There is no universally accepted definition of TRD, but results from the US National Institute of Mental Health's (NIMH) STAR*D (Sequenced Treatment Alternatives to Relieve Depression) programme indicate that after the failure of two treatment trials, the chances of remission decrease significantly. Several pharmacological and nonpharmacological treatments for TRD may be considered when optimized (adequate dose and duration) therapy has not produced a successful outcome and a patient is classified as resistant to treatment. Nonpharmacological strategies include psychotherapy (often in conjunction with pharmacotherapy), electroconvulsive therapy and vagus nerve stimulation. The US FDA recently approved vagus nerve stimulation as adjunctive therapy (after four prior treatment failures); however, its benefits are seen only after prolonged (up to 1 year) use. Other nonpharmacological options, such as repetitive transcranial stimulation, deep brain stimulation or psychosurgery, remain experimental and are not widely available. Pharmacological treatments of TRD can be grouped in two main categories: 'switching' or 'combining'. In the first, treatment is switched within and between classes of compounds. The benefits of switching include avoidance of polypharmacy, a narrower range of treatment-emergent adverse events and lower costs. An inherent disadvantage of any switching strategy is that partial treatment responses resulting from the initial treatment might be lost by its discontinuation in favour of another medication trial. Monotherapy switches have also been shown to have limited effectiveness in achieving remission. The advantage of combination strategies is the potential to build upon achieved improvements; they are generally recommended if partial response was achieved with the current treatment trial. Various non-antidepressant augmenting agents, such as lithium and thyroid hormones, are well studied, although not commonly used. There is also evidence of efficacy and increasing use of atypical antipsychotics in combination with antidepressants, for example, olanzapine in combination with fluoxetine (OFC) or augmentation with aripiprazole. The disadvantages of a combination strategy include multiple medications, a broader range of treatment-emergent adverse events and higher costs. Several experimental pharmaceutical treatment alternatives for TRD are also being explored in combination with antidepressants or as monotherapy. These less studied alternative compounds include pindolol, inositol, CNS stimulants, hormones, herbal supplements, omega-3 fatty acids, S-adenosyl-L-methionine, folic acid, lamotrigine, modafinil, riluzole and topiramate. In summary, despite an increasing variety of choices for the treatment of TRD, this condition remains universally undefined and represents an area of unmet medical need. There are few known approved pharmacological agents for TRD (aripiprazole and OFC) and overall outcomes remain poor. This might be an indication that depression itself is a heterogeneous condition with a great diversity of pathologies, highlighting the need for careful evaluation of individuals with depressive symptoms who are unresponsive to treatment. Clearly, more research is needed to provide clinicians with better guidance in making those treatment decisions--especially in light of accumulating evidence that the longer patients are unsuccessfully treated, the worse their long-term prognosis tends to be.

A paradoxical difference in relationship between anxiety, depression and thyroid function in subjects on and not on T4: findings from the HUNT study

OBJECTIVE

There have been conflicting reports on the relationship between thyroid function and mood between studies in subjects on T4 and the general population not on T4. We investigated this relationship in a large catchment area-based study.

DESIGN

We analysed data on serum TSH levels and Hospital Anxiety and Depression Scale (HADS) scores from the HUNT 2 study (age > or = 40 years). Following a test for interaction, analyses were performed separately in females on T4 (n = 1265) and in people not on T4 (males n = 9319 and females n = 17 694).

RESULTS

More females on T4 had high depression and anxiety scores than females not on T4 (depression 18.4%vs. 13.0%, P < 0.001, anxiety 23.4%vs. 18.7%, P < 0.001). In those not on T4, there was an inverse association between serum TSH and depression score in males (B coefficient = -0.61, 95% CI -0.91 to -0.24, P = 0.001) though not in females (B coefficient = -0.07, -0.33 to 0.19), and an inverse association between TSH and anxiety score in both genders (B coefficient for males = 0.68, 95% CI -1.04 to -0.32, P < 0.001; females -0.37, 95% CI -0.67 to -0.08, P = 0.01). In contrast, in females on T4, TSH was positively associated with both depression (B coefficient = +0.27, 95% CI 0.02 to 0.51, P < 0.05) and anxiety (B coefficient = +0.29, 95% CI 0.01 to 0.56, P < 0.05).

CONCLUSIONS

There is a different relationship between thyroid function and depression and anxiety in females on T4 compared with individuals with no thyroid disease. This group also has a higher prevalence of depression and anxiety.

Canadian Network for Mood and Anxiety Treatments (CANMAT) clinical guidelines for the management of major depressive disorder in adults. III. Pharmacotherapy

BACKGROUND

In 2001, the Canadian Psychiatric Association and the Canadian Network for Mood and Anxiety Treatments (CANMAT) partnered to produce evidence-based clinical guidelines for the treatment of depressive disorders. A revision of these guidelines was undertaken by CANMAT in 2008-2009 to reflect advances in the field.

METHODS

The CANMAT guidelines are based on a question-answer format to enhance accessibility to clinicians. An evidence-based format was used with updated systematic reviews of the literature and recommendations were graded according to Level of Evidence using pre-defined criteria. Lines of Treatment were identified based on criteria that included Levels of Evidence and expert clinical support. This section on "Pharmacotherapy" is one of 5 guideline articles.

RESULTS

Despite emerging data on efficacy and tolerability differences amongst newer antidepressants, variability in patient response precludes identification of specific first choice medications for all patients. All second-generation antidepressants have Level 1 evidence to support efficacy and tolerability and most are considered first-line treatments for MDD. First-generation tricyclic and monoamine oxidase inhibitor antidepressants are not the focus of these guidelines but generally are considered second- or third-line treatments. For inadequate or incomplete response, there is Level 1 evidence for switching strategies and for add-on strategies including lithium and atypical antipsychotics.

LIMITATIONS

Most of the evidence is based on trials for registration and may not reflect real-world effectiveness.

CONCLUSIONS

Second-generation antidepressants are safe, effective and well tolerated treatments for MDD in adults. Evidence-based switching and add-on strategies can be used to optimize response in MDD that is inadequately responsive to monotherapy.

Thyroid disorders in mental patients

PURPOSE OF REVIEW

Thyroid hormones play important roles in brain development and function. Recent findings concerning thyroid hormones secretion, transport, and metabolism in the brain have provided a better understanding of the role of thyroid hormones in mental disorders.

RECENT FINDINGS

The intracellular actions of thyroid hormones in brain are determined by a complex of factors, including circulating concentrations of thyroid hormones, availability of free hormone, activity of thyroid hormone transporters and deiodinase enzymes, and activity of thyroid hormone receptors. Individual genetic variations and mutations of thyroid-axis-related proteins influence thyroid hormone activity in the brain and contribute to the presentation of mental disorders, as well as to response to psychiatric treatments.

SUMMARY

Consideration of molecular mechanism related to genetic alterations in thyroid hormone transport into the neuron, intracellular thyroid hormone metabolism in the brain, as well as polymorphism in thyroid hormone receptors, opens new venues for better understanding of thyroid hormone effects in the brain as well as for finding genetic markers and new targets for the treatment of mental disorders.

Preliminary evidence that a functional polymorphism in type 1 deiodinase is associated with enhanced potentiation of the antidepressant effect of sertraline by triiodothyronine

BACKGROUND

Triiodothyronine (T3) is used to potentiate the clinical effect of antidepressant drugs. Inter-individual differences in efficacy may be related to genetically-based variability in thyroid function.

METHODS

DNA was obtained from 64 patients treated with sertraline plus T3 (SERT-T3, N=35) or plus placebo (SERT-PLB, N=29), for 8 weeks. Antidepressant efficacy was rated with the 21 item Hamilton Rating Scale for Depression (HRSD-21). Functional polymorphisms in type 1 (DIO1-C785T, DIO1-A1814G) and type 2 deiodinase (DIO2-Thr92Ala and DIO2-ORFa-Gly3Asp) were genotyped.

RESULTS

DIO1-C785T was associated with efficacy of T3 but not placebo supplementation, as indicated by the interaction of treatment, DIO1-C758T genotype and time (p=0.04) and a stronger effect of SERT-T3 among DIO1-758T allele carriers (p=0.01). HRSD-21 scores of DIO1-758T allele carriers declined by 68.7+26.6% (mean+SD) over 8 weeks compared to 42.9+37.8% among non-carriers (p=0.02).

DISCUSSION

DIO1 plays a key-role in T4 to T3 conversion and in clearance of the inactive metabolite, rT3. Previous data associate the DIO1-785T allele with lower DIO1 activity. This is consistent with our observation that responders to T3 supplementation had lower baseline serum T3 levels than non-responders. Depressed patients, who have a genetically determined lower T4 to T3 conversion, may be more likely to benefit from T3 supplementation.

Dual- and triple-acting agents for treating core and co-morbid symptoms of major depression: novel concepts, new drugs

The past decade of efforts to find improved treatment for major depression has been dominated by genome-driven programs of rational drug discovery directed toward highly selective ligands for nonmonoaminergic agents. Selective drugs may prove beneficial for specific symptoms, for certain patient subpopulations, or both. However, network analyses of the brain and its dysfunction suggest that agents with multiple and complementary modes of action are more likely to show broad-based efficacy against core and comorbid symptoms of depression. Strategies for improved multitarget exploitation of monoaminergic mechanisms include triple inhibitors of dopamine, serotonin (5-HT) and noradrenaline reuptake, and drugs interfering with feedback actions of monoamines at inhibitory 5-HT(1A), 5-HT(1B) and possibly 5-HT(5A) and 5-HT(7) receptors. Specific subsets of postsynaptic 5-HT receptors mediating antidepressant actions are under study (e.g., 5-HT(4) and 5-HT(6)). Association of a clinically characterized antidepressant mechanism with a nonmonoaminergic component of activity is an attractive strategy. For example, agomelatine (a melatonin agonist/5-HT(2C) antagonist) has clinically proven activity in major depression. Dual neurokinin(1) antagonists/5-HT reuptake inhibitors (SRIs) and melanocortin(4) antagonists/SRIs should display advantages over their selective counterparts, and histamine H(3) antagonists/SRIs, GABA(B) antagonists/SRIs, glutamatergic/SRIs, and cholinergic agents/SRIs may counter the compromised cognitive function of depression. Finally, drugs that suppress 5-HT reuptake and blunt hypothalamo-pituitary-adrenocorticotrophic axis overdrive, or that act at intracellular proteins such as GSK-3beta, may abrogate the negative effects of chronic stress on mood and neuronal integrity. This review discusses the discovery and development of dual- and triple-acting antidepressants, focusing on novel concepts and new drugs disclosed over the last 2 to 3 years.

Simultaneous initiation (coinitiation) of pharmacotherapy with triiodothyronine and a selective serotonin reuptake inhibitor for major depressive disorder: a quantitative synthesis of double-blind studies

To examine the efficacy and overall tolerability of the simultaneous initiation of treatment (coinitiation) with triiodothyronine (T3) and a selective serotonin reuptake inhibitor (SSRI) for major depressive disorder (MDD). Sources of date were Medline/Pubmed, EMBASE, the Cochrane database, and program syllabi from major psychiatric meetings held since 1995. The study selection comprised double-blind, randomized clinical trials comparing T3-SSRI coinitiation therapy versus SSRI monotherapy for MDD. Data were extracted with the use of a precoded form. Data from four clinical trials involving a total of 444 patients with MDD were identified and combined using a random effects model. There was no statistically significant difference in terms of remission rates or response rates at week 1, week 2, or at endpoint between the two treatment groups (SSRI+T3 coinitiation therapy vs. SSRI monotherapy). Pooled response and remission rates at endpoint for the SSRI+T3 versus SSRI monotherapy groups were 64.6 versus 58.5% and 46.8 versus 44.8%, respectively. In addition, there was no statistically significant difference in overall rates of premature discontinuation of treatment, or in the rate of premature discontinuation of treatment owing to inefficacy or intolerance between the two treatment groups. Notwithstanding important methodological differences between the studies included in the meta-analysis in terms of patient characteristics and treatment protocols, these results do not support the notion that simultaneous initiation of treatment of MDD with an SSRI and T3 is more effective than SSRI monotherapy. However, given the etiologically diverse and clinically heterogeneous nature of MDD, it is at least plausible that T3-SSRIs coinitiation therapy may be effective for a particular subgroup of patients including patients with atypical depression or patients with a functional polymorphism of the D-1 deiodinase gene. Clearly, further work is needed to help determine whether there are specific MDD populations that can, indeed, benefit from T3-SSRI coinitiation therapy.