Emerging drugs for major depressive disorder

A review on linking stress, depression, and insulin resistance via low-grade chronic inflammation

Stress is a disturbance in homeostasis caused by psychological, physiological, or environmental factors. Prolonged reactions to chronic stress can be detrimental, resulting in various metabolic abnormalities, referred to as metabolic syndrome (MS). There is a reciprocal increased risk between MS and major depressive disorder. Recent studies established an association between inflammation and insulin signaling in type 2 diabetes mellitus with depression. In the present review, we discuss chronic low-grade inflammation, pathways of insulin resistance, and brain glucose metabolism in the context of neuroinflammation and depression. Specific attention is given to psychotropic drugs such as bupropion, mirtazapine, and nefazodone, anti-inflammatory drugs like Celecoxib (COX-2 inhibitor), Etanercept, adalimumab, IL-4Ra antagonist, Anti-IL- 17A antibody (Ixekizumab) and lifestyle modifications including exercise, dietary changes, and sleep hygiene. These therapeutic solutions offer potential in treating depression by targeting metabolic conditions like insulin resistance and inflammatory pathways. The article further explains the significance of a nutrition and antioxidants-rich diet, emphasizing the role of omega-3 fatty acids, vitamin D, zinc, and polyphenols, to improve immunity and activate anti-inflammatory signaling pathways.

A systematic mapping review of the evolution of the rat Forced Swim Test: Protocols and outcome parameters

As depression is projected to become the leading mental disease burden globally by 2030, understanding the underlying pathology, as well as screening potential anti-depressants with a higher efficacy, faster onset of action, and/or fewer side-effects is essential. A commonly used test for screening novel antidepressants and studying depression-linked aspects in rodents is the Porsolt Forced Swim Test. The present systematic mappping review gives a comprehensive overview of the evolution and of the most prevalently used set-ups of this test in rats, including the choice of animals (strain, sex, and age), technical aspects of protocol and environment, as well as reported outcome measures. Additionally, we provide an accessible list of all existing publications, to support informed decision-making for procedural and technical aspects of the test, to thereby enhance reproducibility and comparability. This should further contribute to reducing the number of unnecessarily replicated experiments, and consequently, reduce the number of animals used in future.

Treating depression in clinical practice: new insights on the multidisciplinary use of trazodone

Depression is estimated to be a leading contributor to the global mental health-related burden. The determinants of this huge prevalence lie in the fact that depressive symptoms may be comorbid in a wide variety of disorders, thus complicating and exacerbating their clinical framework. This makes the treatment of depressive symptoms difficult, since many pharmacological interactions should be considered by physicians planning therapy. Hence, depression still represents a challenge for both psychiatrists and other clinicians, in terms of its high rates of relapse and resistance despite well-established protocols. It is also complicated by the well-known latency in its complete response to current antidepressant treatments. In this context, the search for new strategies regarding antidepressant treatment is mandatory. Revising the use of "old" pharmacotherapies by considering their specific features may help to perfecting the treatment of depression, both in its standalone psychiatric manifestation and in the framework of other clinical conditions. Using a nominal group technique approach, the results of a consensus of expert physicians regarding the possible use of trazodone as a valuable strategy for addressing the "real world" unmet needs of depression treatment in different fields (psychiatry, primary care, neurology and geriatrics) is herein provided. This idea is based on the unique characteristics of this drug which delivers a more rapid antidepressant action as compared to other selective serotonin reuptake inhibitors. It also has pharmacodynamic malleability (i.e., the possibility of exerting different effects on depressive symptoms at different dosages) and pharmacokinetic tolerability (i.e., the possibility of being used as an add-on to other antidepressants with scarce interaction and achieving complimentary effects) when used in the milieu of other drugs in treating comorbid depressive symptoms. Moreover, the large number of formulations available permits finite dosage adjustments, and the use of trazodone for specific pathologies, such as dysphagia. Therefore, although additional studies exploring the real-world conditions of antidepressant treatment are warranted, experts agree on the idea that depressive disorder, in both its standalone and its comorbid manifestations, may surely take advantage of the particular characteristics of trazodone, thus attempting to reach the greatest effectiveness in different contexts.

A unique case of very low-dose subcutaneous ketamine use: Maintenance option of ketamine for treatment-resistant depression

Numerous studies have demonstrated that low-dose subanesthetic intravenous ketamine infusion treatment leads to rapid improvement of treatment-resistant depression. The following case report describes the use of a very low-dose subcutaneous ketamine as a form of maintenance in a patient with severe treatment-resistant depression using a retrospective chart review.

Role of serendipity in the discovery of classical antidepressant drugs: Applying operational criteria and patterns of discovery

The role played by serendipity in the origin of modern psychopharmacology has proven to be controversial in scientific literature. In its original meaning (Walpole), serendipity refers to discoveries made through a combination of accidents and sagacity. We have implemented an operational definition of serendipity based on finding something unexpected or unintended, regardless of the systematic process that led to the accidental observation, and we have established four different patterns of serendipitous attributability. In this paper, we have analyzed the role of serendipity in the discovery and development of classical antidepressant drugs, tricyclic antidepressants and monoamine oxidase inhibitors as well as heterocyclic, “atypical” or “second generation” antidepressants. The discovery of the antidepressant properties of imipramine and iproniazid, the prototypes of tricyclic antidepressants and monoamine oxidase inhibitors, respectively, fits the mixed type II pattern; initial serendipitous discoveries (imipramine was an antipsychotic and iproniazid was an anti-tuberculosis agent) led secondarily to non-serendipitous discoveries. But the other components of these two families of drugs were developed specifically as antidepressants, modifying the chemical structure of the series leaders, thereby allowing all of them to be included in the type IV pattern, characterized by the complete absence of serendipity. Among the heterocyclic drugs, mianserin (originally developed as an antihistamine) also falls into the type II pattern.

A new paradigm shift in antidepressant therapy? From dual-action to multitarget-directed ligands

Major Depressive Disorder is a chronic, recurring, and potentially fatal disease affecting up to 20% of the global population. Since the monoamine hypothesis was proposed more than 60 years ago, only a few relevant advances have been achieved, with very little disease course changing, from a pharmacological perspective. Moreover, since negative efficacy studies with novel molecules are frequent, many pharmaceutical companies have put new studies on hold. Fortunately, relevant clinical studies are currently being performed, and extensive striving is being developed by universities, research centers, and other public and private institutions. Depression is no longer considered a simple disease but a multifactorial one. New research fields are emerging in what could be a paradigm shift: the multitarget approach beyond monoamines. In this review, we summarize the present and the past of antidepressant drug discovery, with the aim to shed some light on the current state of the art in clinical and preclinical advances to face this increasingly devastating disease.

Exploring the mechanisms of action of Cordyceps sinensis for the treatment of depression using network pharmacology and molecular docking

Background

Depression is the most common type of psychological disorder, with continuous, prolonged, and persistent bad moods as the main clinical feature. Cordyceps sinensis is a complex consisting of the ascospores and bodies of insect larvae from the Hepialidae family that have been parasitized by Cordyceps sinensis militaris. Previous studies have reported that this herb has antidepressant activity. The present study used network pharmacology and molecular docking techniques to investigate the potential antidepressant mechanisms of Cordyceps sinensis.

Methods

The active ingredients of Cordycepssinensis were identified using the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP) and the potential targets were predicted using the PharmMapper platform. The GeneCards database was then used to obtain sub-targets for depression. Common targets were screened and enrichment analyses were performed using the Metascape platform. Finally, the relationship between the active ingredients and the core targets were verified by molecular docking.

Results

Through network pharmacological analysis, 7 active ingredients in Cordyceps sinensis and 41 common targets of drugs and diseases were identified. The active ingredients of Cordyceps sinensis may exert antidepressant effects by acting on important targets such as catalase (CAT), CREB binding protein (CREBBP), epidermal growth factor (EGF), and E1A binding protein P300 (EP300), and by modulating the signaling pathways in which these targets are involved. Subsequently, the core targets were docked to the active ingredients and good binding was observed.

Conclusions

The active ingredients of Cordycepssinensis may exert antidepressant effects by regulating the CREB binding protein and anti-oxidative stress effects. The foxo signaling pathway (hsa04068), hypoxia-inducible factor 1 (HIF-1) signaling pathway (hsa04066), and Huntington’s disease (hsa05016) may be involved in the underlying mechanisms of Cordycepssinensis. The joint application of network pharmacology and molecular docking provides a new approach to study the mechanisms of action of traditional Chinese medicine. Cordyceps sinensis may play an important role in the future treatment of patients with depression.

Medicinal chemistry strategies for discovering antivirals effective against drug-resistant viruses

During the last forty years we have witnessed impressive advances in the field of antiviral drug discovery culminating with the introduction of therapies able to stop human immunodeficiency virus (HIV) replication, or cure hepatitis C virus infections in people suffering from liver disease. However, there are important viral diseases without effective treatments, and the emergence of drug resistance threatens the efficacy of successful therapies used today. In this review, we discuss strategies to discover antiviral compounds specifically designed to combat drug resistance. Currently, efforts in this field are focused on targeted proteins (e.g. multi-target drug design strategies), but also on drug conformation (either improving drug positioning in the binding pocket or introducing conformational constraints), in the introduction or exploitation of new binding sites, or in strengthening interaction forces through the introduction of multiple hydrogen bonds, covalent binding, halogen bonds, additional van der Waals forces or multivalent binding. Among the new developments, proteolysis targeting chimeras (PROTACs) have emerged as a valid approach taking advantage of intracellular mechanisms involving protein degradation by the ubiquitin-proteasome system. Finally, several molecules targeting host factors (e.g. human dihydroorotate dehydrogenase and DEAD-box polypeptide 3) have been identified as broad-spectrum antiviral compounds. Implementation of herein described medicinal chemistry strategies are expected to contribute to the discovery of new drugs effective against current and future threats due to emerging and re-emerging viral pandemics.

Role of central serotonin and noradrenaline interactions in the antidepressants' action: Electrophysiological and neurochemical evidence

The development of antidepressant drugs, in the last 6 decades, has been associated with theories based on a deficiency of serotonin (5-HT) and/or noradrenaline (NA) systems. Although the pathophysiology of major depression (MD) is not fully understood, numerous investigations have suggested that treatments with various classes of antidepressant drugs may lead to an enhanced 5-HT and/or adapted NA neurotransmissions. In this review, particular morpho-physiological aspects of these systems are first considered. Second, principal features of central 5-HT/NA interactions are examined. In this regard, the effects of the acute and sustained antidepressant administrations on these systems are discussed. Finally, future directions including novel therapeutic strategies are proposed.

An Overview of the Heterogeneity of Major Depressive Disorder: Current Knowledge and Future Prospective

Major depressive disorder (MDD) is estimated to impose maximum debilitating effects on the society by 2030, with its critical effects on health, functioning, quality of life and concomitant high levels of morbidity and mortality. Yet, the disease is inadequately understood, diagnosed and treated. Moreover, with the recent drastic rise in the pace of life, stress has materialized as one of the most potent environmental factors for depression. In this scenario, it is important to understand the modern pathogenetic hypotheses and mechanisms, and possibly try to shift from the traditional approaches in depression therapy. These include the elaboration of pathophysiological changes in heterogeneous systems such as genetic, epigenetic, serotonergic, noradrenergic, gamma-aminobutyric acid, glutamatergic and endocannabinoid systems, neurotrophic factors, HPA axis, immune system as well as cellular stress mechanisms. These components interact with each other in a complex matrix and further elucidation of their mechanism and cascade pathways are needed. This might aid in the identification of MDD subtypes as well as the development of sophisticated biomarkers. Further, characterization might also aid in developing multitargeted therapies that hold much promise as compared to the conventional monoamine based treatment. New candidate pharmacons, refined psychotherapeutic modalities, advanced neuro-surgical and imaging techniques as well as the implementation of pharmacokinetic, pharmacogenetic prescribing guidelines constitute the emerging expanses of MDD treatment.

Development of the National Network of Depression Centers Mood Outcomes Program: A Multisite Platform for Measurement-Based Care

OBJECTIVES

Mood disorders are among the most burdensome public health concerns. The National Network of Depression Centers (NNDC) is a nonprofit consortium of 26 leading clinical and academic member centers in the United States providing care for patients with mood disorders, including depression and bipolar disorder. The NNDC has established a measurement-based care program called the Mood Outcomes Program whereby participating sites follow a standard protocol to electronically collect patient-reported outcome assessments on depression, anxiety, and suicidal ideation in routine clinical care. This article describes the approaches taken to develop and implement the program.

METHODS

Since 2015, eight pilot sites have implemented the program and followed more than 10,000 patients. This pilot study presents descriptive statistics based on the first 24-month period of data collection.

RESULTS

In this sample, 58.6% of patients with bipolar disorder (N=849) and 57.5% of patients with unipolar depression (N=3,998) remained symptomatic at follow-up. Lifetime rates of planned or actual suicide attempts were high, ranging from 27.6% for patients with unipolar mood disorders to 33.5% for patients with bipolar disorder. Men, unmarried individuals, and those with comorbid anxiety had a poorer longitudinal course. This initial snapshot of clinical burden is consistent with public health data indicating that mood disorders are severely debilitating.

CONCLUSIONS

This study demonstrates the potential of the Mood Outcomes Program to create a nationwide "learning health system" for mood disorders. This goal will be further realized as the program expands in reach and scope across additional NNDC sites.

Antidepressant-like effects of pharmacological inhibition of FAAH activity in socially isolated female rats

Pharmacological inhibition of the enzyme fatty acid amide hydrolase (FAAH), which terminates signaling of the endocannabinoid N-arachidonoylethanolamine (or anandamide, AEA), exerts favourable effects in rodent models of stress-related depression. Yet although depression seems to be more common among women than men and in spite of some evidence of sex differences in treatment efficacy, preclinical development of FAAH inhibitors for the pharmacotherapy of stress-related depression has been predominantly conducted in male animals. Here, adult female rats were exposed to six weeks of social isolation and, starting from the second week, treated with the FAAH inhibitor URB694 (0.3 mg/kg/day, i.p.) or vehicle. Compared to pair-housed females, socially isolated female rats treated with vehicle developed behavioral (mild anhedonia, passive stress coping) and physiological (reduced body weight gain, elevated plasma corticosterone levels) alterations. Moreover, prolonged social isolation provoked a reduction in brain-derived neurotrophic factor (BDNF) and AEA levels within the hippocampus. Together, these changes are indicative of an increased risk of developing a depressive-like state. Conversely, pharmacological inhibition of FAAH activity with URB694 restored both AEA and BDNF levels within the hippocampus of socially isolated rats and prevented the development of behavioral and physiological alterations. These results suggest a potential interplay between AEA-mediated signaling and hippocampal BDNF in the pathogenesis of depression-relevant behaviors and physiological alterations and antidepressant action of FAAH inhibition in socially isolated female rats.

Upregulation of antioxidant thioredoxin by antidepressants fluoxetine and venlafaxine

RATIONALE

Selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs) are the most commonly used drugs for the treatment of depression. Studies have shown that chronic treatment with SSRIs and SNRIs produces a protective effect against oxidative stress. Thioredoxin (Trx) is an antioxidant protein that reverses protein cysteine oxidation and facilitates scavenging reactive oxygen species.

OBJECTIVES

The current study is to determine whether the SSRI fluoxetine and the SNRI venlafaxine regulate Trx and protect neuronal cells against protein cysteine oxidation.

METHODS

HT22 mouse hippocampal cells were incubated with fluoxetine or venlafaxine for 5 days. Protein levels of Trx, Trx reductase (TrxR), and Trx-interacting protein (Txnip) were measured by immunoblotting analysis. Trx and TrxR activities were analyzed by spectrophotometric method. Protein cysteine sulfenylation was measured by dimedone-conjugation assay, while nitrosylation was measured by biotin-switch assay.

RESULTS

We found that treatment with fluoxetine or venlafaxine for 5 days increased Trx and TrxR protein levels but produced no effect on Txnip protein levels. These treatments also increased Trx and TrxR activities. Although treatment with fluoxetine or venlafaxine alone had no effect on sulfenylated and nitrosylated protein levels, both drugs inhibited H₂O₂-increased sulfenylated protein levels and nitric oxide donor nitrosoglutathione-increased nitrosylated protein levels. Stress increases risk of depression. We also found that treatment with fluoxetine or venlafaxine for 5 days inhibited stress hormone corticosterone-increased total sulfenylated and nitrosylated protein levels.

CONCLUSIONS

Our findings suggest that chronic treatment with antidepressants may upregulate Trx, subsequently inhibiting protein sulfenylation and nitrosylation, which may contribute to the protective effect of antidepressants against oxidative stress. Our findings also indicate that thioredoxin is a potential therapeutic target for the treatment of depression.

Peer support for mood disorder: Characteristics and benefits from attending the Depression and Bipolar Support Alliance mutual-help organization

BACKGROUND

Mood disorders (MDs) are pervasive and debilitating psychiatric conditions. Many helpful psychological and psychopharmacological treatments exist, but MD's prevalence and chronicity often means relying purely on professional care can create financial strain on individuals and healthcare systems. Also, many individuals respond only partially to professionally-delivered medical/pharmacological interventions or are unable to tolerate or adhere to them. Peer-led mutual-help organizations (MHOs) have emerged and grown in the U.S. to extend and potentiate professional efforts or otherwise address needs unmet by professional care. The Depression and Bipolar Support Alliance (DBSA) is the largest of these, but beyond observational evidence, little is known about participation or benefits. Greater knowledge could inform the field regarding clinical and public health utility of peer-driven efforts.

METHOD

Community-based cross-sectional comparative investigation of MD individuals attending (N = 202) or not attending (N = 105) DBSA. Measures included demographics, clinical characteristics and clinical service use, and indices of symptomatology, functioning, quality of life (QOL), and psychological well-being.

RESULTS

Compared to non-DBSA participants, DBSA participants were more likely to be male and white and trended toward greater religious affiliation (p = 0.05). DBSA participants attended meetings about twice per month with two-thirds attending for more than one year. The DBSA cohort had a much higher proportion with bipolar I disorder and reported more lifetime and past 90-day use of acute, intensive, medical services and medications. There were no between-group differences on indices of QOL or psychological well-being, but within the DBSA group, greater DBSA attendance and involvement was associated with greater QOL and well-being, and less functional impairment.

LIMITATIONS

Cross-sectional design and regional sampling frame with unknown generalizability to national DBSA membership.

CONCLUSION

Given the grave impact of MDs and that DBSA is freely available it may fill an important clinical and public health need by attracting and engaging MD individuals with greater functional instability and impairment. The positive association found between greater active DBSA participation and improvements in functioning and well-being, while promising, requires longitudinal investigation to formally establish the causal direction of effects.

Depression in primary care: part 2-management

Depression is a common and heterogeneous condition with a chronic and recurrent natural course that is frequently seen in the primary care setting. Primary care providers play a central role in managing depression and concurrent physical comorbidities, and they face challenges in diagnosing and treating the condition. In this two part series, we review the evidence available to help to guide primary care providers and practices to recognize and manage depression. The first review outlined an approach to screening and diagnosing depression in primary care. This second review presents an evidence based approach to the treatment of depression in primary care, detailing the recommended lifestyle, drug, and psychological interventions at the individual level. It also highlights strategies that are being adopted at an organizational level to manage depression more effectively in primary care.

Tactile Stimulation on Adulthood Modifies the HPA Axis, Neurotrophic Factors, and GFAP Signaling Reverting Depression-Like Behavior in Female Rats

Depression is a common psychiatric disease which pharmacological treatment relieves symptoms, but still far from ideal. Tactile stimulation (TS) has shown beneficial influences in neuropsychiatric disorders, but the mechanism of action is not clear. Here, we evaluated the TS influence when applied on adult female rats previously exposed to a reserpine-induced depression-like animal model. Immediately after reserpine model (1 mg/kg/mL, 1×/day, for 3 days), female Wistar rats were submitted to TS (15 min, 3×/day, for 8 days) or not (unhandled). Imipramine (10 mg/kg/mL) was used as positive control. After behavioral assessments, animals were euthanized to collect plasma and prefrontal cortex (PFC). Behavioral observations in the forced swimming test, splash test, and sucrose preference confirmed the reserpine-induced depression-like behavior, which was reversed by TS. Our findings showed that reserpine increased plasma levels of adrenocorticotropic hormone and corticosterone, decreased brain-derived neurotrophic factor (BDNF) and tropomyosin receptor kinase B, and increased proBDNF immunoreactivity in the PFC, which were also reversed by TS. Moreover, TS reestablished glial fibrillary acidic protein and glucocorticoid receptor levels, decreased by reserpine in PFC, while glial cell line-derived neurotrophic factor was increased by TS per se. Our outcomes are showing that TS applied in adulthood exerts a beneficial influence in depression-like behaviors, modulating the HPA axis and regulating neurotrophic factors more effectively than imipramine. Based on this, our proposal is that TS, in the long term, could be considered a new therapeutic strategy for neuropsychiatric disorders improvement in adult life, which may represent an interesting contribution to conventional pharmacological treatment.

Hippocampal Mrp8/14 signaling plays a critical role in the manifestation of depressive-like behaviors in mice

Background

Depression is one of the most common mental disorders characterized mainly by low mood and loss of interest or pleasure. About a third of patients with depression do not respond to classic antidepressant treatments. Recent evidence suggests that Mrp8/14 (myeloid-related protein 8/14) plays a crucial role in cognitive dysfunction and neuroinflammatory diseases, yet its role in mood regulation remains largely uninvestigated. In the present work, we explored the potential role of Mrp8/14 in the progression of depression.

Methods

After 4 weeks of chronic unpredictable mild stress (CUMS), depressive-like symptoms and Mrp8/14 were determined. To verify the effects of Mrp8/14 on depressive-like behaviors, the inhibitor TAK-242 and recombinant Mrp8/14 were used. Furthermore, the molecular mechanisms in Mrp8/14-induced behavioral and biological changes were examined in vivo and ex vivo.

Results

Four-week CUMS contributed to the development of depressive symptoms. Mrp8 and Mrp14 were upregulated in the hippocampus and serum after exposure to CUMS. Pharmacological inhibition of Mrp14 attenuated CUMS-induced TLR4/NF-κB signaling activation and depressive-like behaviors. Furthermore, central administration of recombinant Mrp8, Mrp14, and Mrp8/14 resulted in neuroinflammation and depressive-like behaviors. Mrp8/14-provoked proinflammatory effects and depressive-like behaviors were improved by pretreatment with a TLR4 inhibitor. Moreover, pharmacological inhibition of TLR4 reduced the release of nitric oxide and reactive oxygen species in Mrp8/14-activated BV2 microglia.

Conclusions

These data suggest that the hippocampal Mrp8/14-TLR4-mediated neuroinflammation contributes to the development of depressive-like behaviors. Targeting the Mrp8/14 may be a novel promising antidepressant approach.

Electronic supplementary material

The online version of this article (10.1186/s12974-018-1296-0) contains supplementary material, which is available to authorized users.

Genome-wide analysis of LPS-induced inflammatory response in the rat ventral hippocampus: Modulatory activity of the antidepressant agomelatine

OBJECTIVES

Several studies reported that antidepressant drugs have immune-regulatory effects by acting on specific inflammatory mediators. However, considering the highly complex nature of the inflammatory response, we have adopted an unbiased genome-wide strategy to investigate the immune-regulatory activity of the antidepressant agomelatine in modulating the response to an acute inflammatory challenge.

METHODS

Microarray analysis was used to identify genes modulated in the ventral hippocampus of adult rats chronically treated with agomelatine (40 mg/kg, os) before being challenged with a single injection of lipopolysaccharide (LPS; 250 μg/kg, i.p.).

RESULTS

The administration of LPS induced the transcription of 284 genes mainly associated with pathways related to the immune/inflammatory system. Agomelatine modulated pathways not only connected to its antidepressant activity, but was also able to prevent the activation of genes induced by LPS. Further comparisons between gene lists of the diverse experimental groups led to the identification of a few transcripts modulated by LPS on which agomelatine has the larger effect of normalisation. Among them, we found the pro-inflammatory cytokine Il-1β and, interestingly, the metabotropic glutamatergic transporter Grm2.

CONCLUSIONS

These results are useful to better characterise the association between depression and inflammation, revealing new potential targets for pharmacological intervention for depression associated to inflammation.

Silibinin exerts antidepressant effects by improving neurogenesis through BDNF/TrkB pathway

Classic antidepressants benefit depression patients partially by improving neurogenesis and/or brain-derived neurotrophic factor (BDNF)/TrkB pathway which were impaired in depression. In this study, we demonstrated that Silibinin (SLB), a polyphenolic flavanoid from Silybum marianum, ameliorated reserpinized mouse depressant-like behaviors. The antidepressants of SLB administration was associated with increased neural stem cells (NSCs) proliferation and further confirmed in BDNF/TrkB signaling transduction. SLB treatment reversed the decreased expression levels of BDNF and its receptor TrkB, and the reduced activation of downstream target proteins including phosphorylated extracellular-regulated protein kinase (p-ERK) and phosphorylated cAMP-response element binding protein (p-CREB) in depressived hippocampus. Furthermore, intracerebroventricular injection of GNF5837, a TrkB antagonist, abrogated antidepressant-like effects of SLB in mice along with the improved NSC proliferation, as well as enhanced levels of p-ERK and p-CREB in mice hippocampus. Taken together, these results suggest that SLB may exert antidepressant effects through BDNF/TrkB signaling pathway to improve NSC proliferation in acute depression.

Self-Reported Adverse Drug Reactions, Medication Adherence, and Clinical Outcomes among Major Depressive Disorder Patients in Ethiopia: A Prospective Hospital Based Study

BACKGROUND

There is paucity of data on prevalence of Adverse Drug Reactions (ADRs) and adherence and clinical outcomes of antidepressants. The present study determined the magnitude of ADRs of antidepressants and their impact on the level of adherence and clinical outcome.

METHODS

A prospective cross-sectional study was conducted among depression patients from September 2016 to January 2017 at Gondar University Hospital psychiatry clinic. The Naranjo ADR probability scale was employed to assess the ADRs. The rate of medication adherence was determined using Morisky Medication Adherence Measurement Scale-Eight.

RESULTS

Two hundred seventeen patients participated in the study, more than half of them being males (122; 56.2%). More than one-half of the subjects had low adherence to their medications (124; 57.1%) and about 186 (85.7%) of the patients encountered ADR. The most common ADR was weight gain (29; 13.2%). More than one-half (125; 57.6%) of the respondents showed improved clinical outcome. Optimal level of medication adherence decreased the likelihood of poor clinical outcome by 56.8%.

CONCLUSION

ADRs were more prevalent. However, adherence to medications was very poor in the setup. Long duration of depression negatively affects the rate of adherence. In addition, adherence was found to influence the clinical outcome of depression patients.

Saikosaponin D relieves unpredictable chronic mild stress induced depressive-like behavior in rats: involvement of HPA axis and hippocampal neurogenesis

RATIONALE

Saikosaponin D (SSD), a major bioactive component isolated from Radix Bupleuri, has been reported to exert neuroprotective properties.

OBJECTIVES

The present study was designed to investigate the anti-depressant-like effects and the potential mechanisms of SSD.

METHODS

Behavioural tests including sucrose preference test (SPT), open field test (OFT) and forced swim test (FST) were performed to study the antidepressant-like effects of SSD. In addition, we examined corticosterone and glucocorticoid receptor (GR) levels to evaluate hypothalamic-pituitary-adrenal (HPA) axis function. Furthermore, hippocampal neurogenesis was assessed by testing doublecortin (DCX) levels, and neurotrophic molecule levels were also investigated in the hippocampus of rats.

RESULTS

We found that unpredictable chronic mild stress (UCMS) rats displayed lost body weight, decreased sucrose consumption in SPT, reduced locomotive activity in OFT, and increased immobility time in FST. Chronic treatment with SSD (0.75, 1.50 mg/kg) remarkably ameliorated the behavioral deficiency induced by UCMS procedure. SSD administration downregulated elevated serum corticosterone levels, as well as alleviated the suppression of GR expression and nuclear translocation caused by UCMS, suggesting that SSD is able to remit the dysfunction of HPA axis. In addition, Western blot and immunohistochemistry analysis showed that SSD treatment significantly increased the generation of neurons in the hippocampus of UCMS rats indicated by elevated DCX levels. Moreover, hippocampal neurotrophic molecule levels of UCMS rats such as phosphorylated cAMP response element binding protein (p-CREB) and brain-derived neurotrophic factor (BDNF) were raised after SSD treatment.

CONCLUSIONS

Together, Our results suggest that SSD opposed UCMS-induced depressive behaviors in rats, which was mediated, partially, by the enhancement of HPA axis function and consolidation of hippocampal neurogenesis.

A meta-analysis of the efficacy of venlafaxine extended release 75-225 mg/day for the treatment of major depressive disorder

OBJECTIVE

To evaluate the short-term efficacy of venlafaxine extended release (ER) 75-225 mg/day compared with placebo for treating major depressive disorder (MDD) and to examine associations between baseline characteristics and efficacy outcomes in MDD patients treated with venlafaxine ER 75-225 mg/day.

RESEARCH DESIGN AND METHODS

This meta-analysis included published and unpublished short-term, double-blind, placebo-controlled, Wyeth/Pfizer sponsored studies of venlafaxine ER at doses up to 225 mg/day in adults with MDD.

CLINICAL TRIAL REGISTRATION

All trials were conducted before trial registration became mandatory.

MAIN OUTCOME MEASURES

Change from baseline in the 17-item Hamilton Rating Scale for Depression (HAM-D₁₇) total score was analyzed over time using a mixed-effects model for repeated measures with terms for study, treatment group, visit, interaction between treatment group and visit, and baseline score as a covariate. Associations between baseline demographic and clinical characteristics and the probability of HAM-D₁₇ response and remission at week 8 were evaluated using logistic regression models, with terms for study, treatment group, and baseline characteristics in the models. Safety and tolerability was assessed based on adverse events (AEs) and discontinuations due to AEs.

RESULTS

The full analysis set included 1087 patients from five studies that fulfilled selection criteria. Statistically significant separation between venlafaxine ER and placebo groups for HAM-D₁₇ total score was seen at week 2 and all subsequent assessments (p-values <.0001). There was no significant interaction between treatment and baseline HAM-D₁₇ total score. Probability of HAM-D₁₇ remission at week 8 decreased with increasing baseline HAM-D₁₇ total score (p = .0012; OR: 0.94); however, baseline HAM-D₁₇ total score did not predict response. Discontinuations due to AEs were reported for 9.4% of venlafaxine-ER-treated patients compared with 3.6% of placebo-treated patients. Key limitations: Five studies met the criteria for inclusion. Several differences in design between included studies limited the analysis: one study did not include a week 3 assessment (the week 3 time point was therefore dropped from the analysis), one study had two venlafaxine ER dose arms, which were combined into one group for the meta-analysis, and mixed- and flexible-dose studies were pooled.

CONCLUSIONS

Venlafaxine ER 75-225 mg/day effectively reduced symptoms of depression in patients with MDD overall and in patients with either lower (≤23) or higher (>23) HAM-D₁₇ total score at baseline.

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.

Current Problems in the Research and Development of more Effective Antidepressants

This commentary was stimulated by discussions held at the First China Antidepressants Research and Development Summit held in Beijing in October 2015. Hosted by the Chinese Psychiatrist Psychopharmacology Commission and including leading clinicians, neuroscientists, and representatives of the pharmaceutical industry, the summit focused on the major problems that are limiting the development of more effective antidepressant medications. In the absence of clear biomarkers of depression, clinicians must base treatment decisions on clinical phenomenology; the lack of clear biological targets results in currently available antidepressants that take a long time to be effective, have low rates of full remission, and high rates of relapse. Basic research on depression by neuroscientists in China is internationally recognized, but the vast proportion of candidate chemical compounds Chinese researchers propose as potential treatments for depression fail when tested clinically. This high failure rate of proposed agents has rapidly increased the cost of bringing new drugs to market, so pharmaceutical firms prefer to ‘tweak’ currently approved medications rather than take the financial risk of supporting the development of novel antidepressants. Thus, the development of new, more effective treatments for depression is at a stalemate. Given the huge impact of depression on the economic development of China and other countries, it is essential to actively solicit the support of governments and communities in the efforts of clinicians, researchers, and the pharmaceutical industry to overcome this stalemate.

Ketamine for Treatment of Suicidal Ideation and Reduction of Risk for Suicidal Behavior

Ketamine, an NMDA receptor antagonist with efficacy as a rapid anti-depressant, has early evidence for action to reduce suicidal ideation. This review will explore several important questions that arise from these studies. First, how do we measure reductions in suicidal ideation that occur over minutes to hours? Second, are the reductions in suicidal ideation after ketamine treatment solely a result of its rapid anti-depressant effect? Third, is ketamine only effective in reducing suicidal ideation in patients with mood disorders? Fourth, could ketamine's action lead us to a greater understanding of the neurobiology of suicidal processes? Last, do the reductions in depression and suicidal ideation after ketamine treatment translate into decreased risk for suicidal behavior? Our review concludes that ketamine treatment can be seen as a double-edged sword, clinically to help provide treatment for acutely suicidal patients and experimentally to explore the neurobiological nature of suicidal ideation and suicidal behavior.

A double-tracer technique to characterize absorption, distribution, metabolism and excretion (ADME) of [14C]-basimglurant and absolute bioavailability after oral administration and concomitant intravenous microdose administration of [13C6]-labeled basimglurant in humans

1. The emerging technique of employing intravenous microdose administration of an isotope tracer concomitantly with an [¹⁴C]-labeled oral dose was used to characterize the disposition and absolute bioavailability of a novel metabotropic glutamate 5 (mGlu5) receptor antagonist under clinical development for major depressive disorder (MDD). 2. Six healthy volunteers received a single 1 mg [¹²C/¹⁴C]-basimglurant (2.22 MBq) oral dose and a concomitant i.v. tracer dose of 100 μg of [¹³C₆]-basimglurant. Concentrations of [¹²C]-basimglurant and the stable isotope [¹³C₆]-basimglurant were determined in plasma by a specific LC/MS-MS method. Total [¹⁴C] radioactivity was determined in whole blood, plasma, urine and feces by liquid scintillation counting. Metabolic profiling was conducted in plasma, urine, blood cell pellet and feces samples. 3. The mean absolute bioavailability after oral administration (F) of basimglurant was ∼67% (range 45.7-77.7%). The major route of [¹⁴C]-radioactivity excretion, primarily in form of metabolites, was in urine (mean recovery 73.4%), with the remainder excreted in feces (mean recovery 26.5%). The median t_max for [¹²C]-basimglurant after the oral administration was 0.71 h (range 0.58-1.00) and the mean terminal half-life was 77.2 ± 38.5 h. Terminal half-life for the [¹⁴C]-basimglurant was 178 h indicating presence of metabolites with a longer terminal half-life. Five metabolites were identified with M1-Glucuronide as major and the others in trace amounts. There was minimal binding of drug to RBCs. IV pharmacokinetics was characterized with a mean ± SD CL of 11.8 ± 7.4 mL/h and a Vss of 677 ± 229 L. 4. The double-tracer technique used in this study allowed to simultaneously characterize the absolute bioavailability and disposition characteristics of the new oral molecular entity in a single study.

Sigma receptors [σRs]: biology in normal and diseased states

This review compares the biological and physiological function of Sigma receptors [σRs] and their potential therapeutic roles. Sigma receptors are widespread in the central nervous system and across multiple peripheral tissues. σRs consist of sigma receptor one (σ₁R) and sigma receptor two (σ₂R) and are expressed in numerous regions of the brain. The sigma receptor was originally proposed as a subtype of opioid receptors and was suggested to contribute to the delusions and psychoses induced by benzomorphans such as SKF-10047 and pentazocine. Later studies confirmed that σRs are non-opioid receptors (not an µ opioid receptor) and play a more diverse role in intracellular signaling, apoptosis and metabolic regulation. σ₁Rs are intracellular receptors acting as chaperone proteins that modulate Ca²⁺ signaling through the IP₃ receptor. They dynamically translocate inside cells, hence are transmembrane proteins. The σ₁R receptor, at the mitochondrial-associated endoplasmic reticulum membrane, is responsible for mitochondrial metabolic regulation and promotes mitochondrial energy depletion and apoptosis. Studies have demonstrated that they play a role as a modulator of ion channels (K⁺ channels; N-methyl-d-aspartate receptors [NMDAR]; inositol 1,3,5 triphosphate receptors) and regulate lipid transport and metabolism, neuritogenesis, cellular differentiation and myelination in the brain. σ₁R modulation of Ca²⁺ release, modulation of cardiac myocyte contractility and may have links to G-proteins. It has been proposed that σ₁Rs are intracellular signal transduction amplifiers. This review of the literature examines the mechanism of action of the σRs, their interaction with neurotransmitters, pharmacology, location and adverse effects mediated through them.

Developments in the field of antidepressants, where do we go now?

Major depression is a severe psychiatric syndrome with very high prevalence and socio-economic impact. Its pathophysiology is poorly known, yet several neurotransmitter systems and brain areas have been implicated. Selective serotonin (5-hydroxytryptamine, 5-HT) reuptake inhibitors (SSRI) and serotonin and norepinephrine reuptake inhibitors (SNRI) are most used antidepressant treatments. However, these drugs show slow onset of action and limited efficacy, making necessary the use of drug augmentation strategies or more aggressive interventions. Two important observations have emerged in recent years indicating that more rapid and effective antidepressant treatments are possible. Hence, the deep brain stimulation (DBS) of ventral anterior (subgenual) cingulate cortex (Cg25) evokes rapid mood improvements in subgroups of treatment-resistant depressive patients, likely mediated by a functional remodelling of cortico-limbic circuits. On the other hand, the non-competitive NDMA receptor antagonist ketamine can also evoke rapid (e.g., 2h) and persistent (up to 1 wk) improvements in some treatment-resistant patients. Moreover, recent preclinical observations indicate the antidepressant capacity of mGluR agents. Overall, this supports the usefulness of glutamatergic transmission as a new area in antidepressant drug development. On the monoamine side, new preclinical and clinical research should clarify the different roles played by 5-HT receptors in depression as well as the brain areas and circuits responsible for therapeutic improvement. This will lead to the synthesis of new agents blocking the serotonin (and possibly norepinephrine) transporter which will also activate or block 5-HT receptors playing respectively positive (e.g., postsynaptic 5-HT1A, 5-HT4) or negative (e.g., presynaptic 5-HT1A,/1B, 5-HT2A, 5-HT2C,5-HT3, etc.) roles in antidepressant effects.

60 years of advances in neuropsychopharmacology for improving brain health, renewed hope for progress

Pharmacotherapy is effective in helping many patients suffering from psychiatric and neurological disorders, and both psychotherapeutic and stimulation-based techniques likewise have important roles to play in their treatment. However, therapeutic progress has recently been slow. Future success for improving the control and prevention of brain disorders will depend upon deeper insights into their causes and pathophysiological substrates. It will also necessitate new and more rigorous methods for identifying, validating, developing and clinically deploying new treatments. A field of Research and Development (R and D) that remains critical to this endeavour is Neuropsychopharmacology which transformed the lives of patients by introducing pharmacological treatments for psychiatric disorder some 60 years ago. For about half of this time, the European College of Neuropsychopharmacology (ECNP) has fostered efforts to enhance our understanding of the brain, and to improve the management of psychiatric disorders. Further, together with partners in academia and industry, and in discussions with regulators and patients, the ECNP is implicated in new initiatives to achieve this goal. This is then an opportune moment to survey the field, to analyse what we have learned from the achievements and failures of the past, and to identify major challenges for the future. It is also important to highlight strategies that are being put in place in the quest for more effective treatment of brain disorders: from experimental research and drug discovery to clinical development and collaborative ventures for reinforcing "R and D". The present article sets the scene, then introduces and interlinks the eight articles that comprise this Special Volume of European Neuropsychopharmacology. A broad-based suite of themes is covered embracing: the past, present and future of "R and D" for psychiatric disorders; complementary contributions of genetics and epigenetics; efforts to improve the treatment of depression, neurodevelopmental and neurodegenerative disorders; and advances in the analysis and neuroimaging of cellular and cerebral circuits.

Learning from the past and looking to the future: Emerging perspectives for improving the treatment of psychiatric disorders

Modern neuropsychopharmacology commenced in the 1950s with the serendipitous discovery of first-generation antipsychotics and antidepressants which were therapeutically effective yet had marked adverse effects. Today, a broader palette of safer and better-tolerated agents is available for helping people that suffer from schizophrenia, depression and other psychiatric disorders, while complementary approaches like psychotherapy also have important roles to play in their treatment, both alone and in association with medication. Nonetheless, despite considerable efforts, current management is still only partially effective, and highly-prevalent psychiatric disorders of the brain continue to represent a huge personal and socio-economic burden. The lack of success in discovering more effective pharmacotherapy has contributed, together with many other factors, to a relative disengagement by pharmaceutical firms from neuropsychiatry. Nonetheless, interest remains high, and partnerships are proliferating with academic centres which are increasingly integrating drug discovery and translational research into their traditional activities. This is, then, a time of transition and an opportune moment to thoroughly survey the field. Accordingly, the present paper, first, chronicles the discovery and development of psychotropic agents, focusing in particular on their mechanisms of action and therapeutic utility, and how problems faced were eventually overcome. Second, it discusses the lessons learned from past successes and failures, and how they are being applied to promote future progress. Third, it comprehensively surveys emerging strategies that are (1), improving our understanding of the diagnosis and classification of psychiatric disorders; (2), deepening knowledge of their underlying risk factors and pathophysiological substrates; (3), refining cellular and animal models for discovery and validation of novel therapeutic agents; (4), improving the design and outcome of clinical trials; (5), moving towards reliable biomarkers of patient subpopulations and medication efficacy and (6), promoting collaborative approaches to innovation by uniting key partners from the regulators, industry and academia to patients. Notwithstanding the challenges ahead, the many changes and ideas articulated herein provide new hope and something of a framework for progress towards the improved prevention and relief of psychiatric and other CNS disorders, an urgent mission for our Century.

Antidepressant-like effect of sodium butyrate is associated with an increase in TET1 and in 5-hydroxymethylation levels in the Bdnf gene

BACKGROUND

Epigenetic drugs like sodium butyrate (NaB) show antidepressant-like effects in preclinical studies, but the exact molecular mechanisms of the antidepressant effects remain unknown. While research using NaB has mainly focused on its role as a histone deacetylase inhibitor (HDACi), there is also evidence that NaB affects DNA methylation.

METHODS

The purpose of this study was to examine NaB's putative antidepressant-like efficacy in relation to DNA methylation changes in the prefrontal cortex of an established genetic rat model of depression (the Flinders Sensitive Line [FSL]) and its controls (the Flinders Resistant Line).

RESULTS

The FSL rats had lower levels of ten-eleven translocation methylcytosine dioxygenase 1 (TET1), which catalyzes the conversion of DNA methylation to hydroxymethylation. As indicated by the behavioral despair test, chronic administration of NaB had antidepressant-like effects in the FSL and was accompanied by increased levels of TET1. The TET1 upregulation was also associated with an increase of hydroxymethylation and a decrease of methylation in brain-derived neurotrophic factor (Bdnf), a gene associated with neurogenesis and synaptic plasticity. These epigenetic changes were associated with a corresponding BDNF overexpression.

CONCLUSIONS

Our data support the antidepressant efficacy of HDACis and suggest that their epigenetic effects may also include DNA methylation changes that are mediated by demethylation-facilitating enzymes like TET1.

Health resource use and costs of vilazodone and other selective serotonin re-uptake inhibitors in treating major depressive disorder

OBJECTIVE

Selective serotonin re-uptake inhibitors (SSRIs) are widely prescribed antidepressants. This claims database study compared healthcare resource use and costs among patients with major depressive disorder (MDD) treated with vilazodone vs other SSRIs.

METHODS

Adults with an MDD diagnosis and ≥ 1 prescription fill for vilazodone, citalopram, escitalopram, fluoxetine, paroxetine, or sertraline were identified from administrative claims data (2010-2012). Patients who concomitantly used adjunctive medication, either a second-generation antidepressant or antipsychotic, were excluded. All-cause and MDD-related healthcare resource use and costs (in 2012 USD) were compared between patients treated with vilazodone vs other SSRIs over a 6-month follow-up period using unadjusted and multivariable analyses.

RESULTS

The study cohort included 49 861 patients (mean age = 44.0 years; 70% female). Compared with the vilazodone cohort (n = 3527), patients in the citalopram (n = 12 187), escitalopram (n = 8275), fluoxetine (n = 10 142), paroxetine (n = 3146), and sertraline (n = 12 584) cohorts had significantly more all-cause inpatient hospital visits, longer hospital stays and more frequent emergency department visits, following the index date, after adjusting for baseline characteristics. All-cause medical service costs (inpatient + outpatient + emergency department visits) were significantly higher across all other SSRI cohorts vs vilazodone by $758-$1165 (p < 0.05). Similarly, all-cause total costs, were significantly or numerically (non-significantly) higher across all SSRI cohorts vs vilazodone by $351-$780.

LIMITATIONS

The was no clinical measurement of disease severity, partial coverage of the Medicare-eligible population, and short follow-up.

CONCLUSION

MDD treatment with vilazodone was associated with significantly lower rates of inpatient and emergency services, and with significantly lower all-cause medical service costs and numerically (non-significantly) lower total costs to payers than with the other SSRIs included in this study.

Mechanisms Underlying Motivational Deficits in Psychopathology: Similarities and Differences in Depression and Schizophrenia

Motivational and hedonic impairments are core aspects of a variety of types of psychopathology. These impairments cut across diagnostic categories and may be critical to understanding major aspects of the functional impairments accompanying psychopathology. Given the centrality of motivational and hedonic systems to psychopathology, the Research Domain Criteria (RDoC) initiative includes a "positive valence" systems domain that outlines a number of constructs that may be key to understanding the nature and mechanisms of motivational and hedonic impairments in psychopathology. These component constructs include initial responsiveness to reward, reward anticipation or expectancy, incentive or reinforcement learning, effort valuation, and action selection. Here, we review behavioral and neuroimaging studies providing evidence for impairments in these constructs in individuals with psychosis versus in individuals with depressive pathology. There are important differences in the nature of reward-related and hedonic deficits associated with psychosis versus depression that have major implications for our understanding of etiology and treatment development. In particular, the literature strongly suggests the presence of impairments in in-the-moment hedonics or "liking" in individuals with depressive pathology, particularly among those who experience anhedonia. Such deficits may propagate forward and contribute to impairments in other constructs that are dependent on hedonic responses, such as anticipation, learning, effort, and action selection. Such hedonic impairments could reflect alterations in dopamine and/or opioid signaling in the striatum related to depression or specifically to anhedonia in depressed populations. In contrast, the literature points to relatively intact in-the-moment hedonic processing in psychosis, but provides much evidence for impairments in other components involved in translating reward to action selection. Particularly, individuals with schizophrenia exhibit altered reward prediction and associated striatal and prefrontal activation, impaired reward learning, and impaired reward-modulated action selection.

Ketamine, Transcranial Magnetic Stimulation, and Depression Specific Yoga and Mindfulness Based Cognitive Therapy in Management of Treatment Resistant Depression: Review and Some Data on Efficacy

Depression affects about 121 million people worldwide and prevalence of major depressive disorder (MDD) in US adults is 6.4%. Treatment resistant depression (TRD) accounts for approximately 12-20% of all depression patients and costs $29-$48 billion annually. Ketamine and repetitive transcranial magnetic stimulation (rTMS) have useful roles in TRD, but their utility in long term is unknown. As per the latest literature, the interventions using Yoga and meditation including the mindfulness based cognitive therapy (MBCT) have been useful in treatment of depression and relapse prevention. We present a review of rTMS, ketamine, and MBCT and also report efficacy of a depression specific, innovative, and translational model of Yoga and mindfulness based cognitive therapy (DepS Y-MBCT), developed by the first author. DepS Y-MBCT as an adjunctive treatment successfully ameliorated TRD symptoms in 27/32 patients in an open label pilot trial in TRD patients. Considering the limitations of existing treatment options, including those of ketamine and rTMS when used as the sole modality of treatment, we suggest a "tiered approach for TRD" by combining ketamine and rTMS (alone or along with antidepressants) for rapid remission of acute depression symptoms and to use DepS Y-MBCT for maintaining remission and preventing relapse.

Proteomics, metabolomics, and protein interactomics in the characterization of the molecular features of major depressive disorder

Omics technologies emerged as complementary strategies to genomics in the attempt to understand human illnesses. In general, proteomics technologies emerged earlier than those of metabolomics for major depressive disorder (MDD) research, but both are driven by the identification of proteins and/or metabolites that can delineate a comprehensive characterization of MDD's molecular mechanisms, as well as lead to the identification of biomarker candidates of all types—prognosis, diagnosis, treatment, and patient stratification. Also, one can explore protein and metabolite interactomes in order to pinpoint additional molecules associated with the disease that had not been picked up initially. Here, results and methodological aspects of MDD research using proteomics, metabolomics, and protein interactomics are reviewed, focusing on human samples.

Hypothalamic-pituitary-adrenocortical axis: neuropsychiatric aspects

Evidence of aberrant hypothalamic-pituitary-adrenocortical (HPA) activity in many psychiatric disorders, although not universal, has sparked long-standing interest in HPA hormones as biomarkers of disease or treatment response. HPA activity may be chronically elevated in melancholic depression, panic disorder, obsessive-compulsive disorder, and schizophrenia. The HPA axis may be more reactive to stress in social anxiety disorder and autism spectrum disorders. In contrast, HPA activity is more likely to be low in PTSD and atypical depression. Antidepressants are widely considered to inhibit HPA activity, although inhibition is not unanimously reported in the literature. There is evidence, also uneven, that the mood stabilizers lithium and carbamazepine have the potential to augment HPA measures, while benzodiazepines, atypical antipsychotics, and to some extent, typical antipsychotics have the potential to inhibit HPA activity. Currently, the most reliable use of HPA measures in most disorders is to predict the likelihood of relapse, although changes in HPA activity have also been proposed to play a role in the clinical benefits of psychiatric treatments. Greater attention to patient heterogeneity and more consistent approaches to assessing treatment effects on HPA function may solidify the value of HPA measures in predicting treatment response or developing novel strategies to manage psychiatric disease.

Efficacy and safety of olanzapine/fluoxetine combination vs fluoxetine monotherapy following successful combination therapy of treatment-resistant major depressive disorder

This study assessed prevention of relapse in patients with treatment-resistant depression (TRD) taking olanzapine/fluoxetine combination (OFC). Patients with major depressive disorder (MDD) who failed to satisfactorily respond to ≥ 2 different antidepressants for ≥ 6 weeks within the current MDD episode were acutely treated for 6-8 weeks, followed by stabilization (12 weeks) on OFC. Those who remained stable were randomized to OFC or fluoxetine for up to 27 weeks. Time-to-relapse was the primary efficacy outcome defined as 50% increase in Montgomery-Åsberg Depression Rating Scale score with Clinical Global Impressions-Severity of Depression score of ≥ 4; hospitalization for depression or suicidality; or discontinuation for lack of efficacy or worsening of depression or suicidality. A total of 444 patients were randomized 1:1 to OFC (N=221) or fluoxetine (N=223). Time-to-relapse was significantly longer in OFC-treated patients compared with fluoxetine-treated patients (p<0.001). Treatment-emergent weight gain and some mean and categorical fasting metabolic changes were significantly greater in OFC-treated patients. Clinically significant weight gain (≥ 7%) was observed in 55.7% of patients who remained on OFC throughout the study, including the relapse-prevention phase (up to 47 weeks). There were no significant differences between patients treated with OFC and fluoxetine in extrapyramidal symptoms or serious adverse events. We believe this is the first controlled relapse-prevention study in subjects with TRD that supports continued use of a second-generation antipsychotic beyond stabilization. A thorough assessment of benefits and risks (in particular metabolic changes) associated with continuing treatment with OFC or fluoxetine must be done based on individual patient needs.

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.

On 'polypharmacy' and multi-target agents, complementary strategies for improving the treatment of depression: a comparative appraisal

Major depression is a heterogeneous disorder, both in terms of symptoms, ranging from anhedonia to cognitive impairment, and in terms of pathogenesis, with many interacting genetic, epigenetic, developmental and environmental causes. Accordingly, it seems unlikely that depressive states could be fully controlled by a drug possessing one discrete mechanism of action and, in the wake of disappointing results with several classes of highly selective agent, multi-modal treatment concepts are attracting attention. As concerns pharmacotherapy, there are essentially two core strategies. First, multi-target antidepressants that act via two or more complementary mechanisms and, second, polypharmacy, which refers to co-administration of two distinct drugs, usually in separate pills. Both multi-target agents and polypharmacy ideally couple a therapeutically unexploited action to a clinically established mechanism in order to enhance efficacy, moderate side-effects, accelerate onset of action and treat a broader range of symptoms. The melatonin MT1/MT2 agonist and 5-HT(2C) antagonist, agomelatine, which is effective in the short- and long-term treatment of depression, exemplifies the former approach, while evidence-based polypharmacy is illustrated by the adjunctive use of second-generation antipsychotics with serotonin reuptake inhibitors for treatment of resistant depression. Histone acetylation and methylation, ghrelin signalling, inflammatory modulators, metabotropic glutamate-7 receptors and trace amine-associated-1 receptors comprise attractive substrates for new multi-target and polypharmaceutical strategies. The present article outlines the rationale underpinning multi-modal approaches for treating depression, and critically compares and contrasts the pros and cons of established and potentially novel multi-target vs. polypharmaceutical treatments. On balance, the former appear the most promising for the elaboration, development and clinical implementation of innovative concepts for the more effective management of depression.

Resolution of sleepiness and fatigue: a comparison of bupropion and selective serotonin reuptake inhibitors in subjects with major depressive disorder achieving remission at doses approved in the European Union

Unlike selective serotonin reuptake inhibitors (SSRIs), bupropion may be classified as a dual noradrenaline and dopamine reuptake inhibitor, a difference with potential implications for the treatment of residual sleepiness and fatigue in major depressive disorder (MDD). Post-hoc analysis of subjects with remitted MDD was performed on data pooled from six double-blind, randomized trials comparing the European Union (EU)-approved dose of ≤300 mg/day bupropion with SSRIs (sertraline, paroxetine or escitalopram) for the resolution of sleepiness and fatigue. Hypersomnia score was defined as the sum of scores of the Hamilton Depression Rating Scale (HDRS) items 22, 23, and 24; fatigue score as HDRS item 13 score; and remission as HDRS-17≤7. Similar proportions of bupropion- and SSRI-treated subjects achieved remission at study endpoint (169/343, 49.3% vs 324/656, 49.4%; last observation carried forward (LOCF), p=0.45). Fewer bupropion-treated remitters had residual symptoms of sleepiness (32/169, 18.9% vs 104/324, 32.1%; p<0.01) and fatigue (33/169, 19.5% vs 98/324, 30.2%; p<0.05). Bupropion-treated remitters also showed greater improvement (mean change from baseline) in sleepiness (p<0.05) and fatigue scores (p<0.01) at endpoint: benefits were evident from week 2 for sleepiness (p<0.01) and week 4 for fatigue (p<0.01). Bupropion treatment at the EU-approved dose of ≤300 mg/day may offer advantages over SSRIs in the resolution of sleepiness and fatigue in remitted MDD patients.

Novel agents in development for the treatment of depression

There are several investigational drugs in development for the treatment of depression. Some of the novel antidepressants in development target monoaminergic neurotransmission in accordance with the "monoamine hypothesis of depression." However, the current conceptualization of antidepressant actions is that it is the downstream effects on protein synthesis and neuroplasticity that account for therapeutic efficacy, rather than the immediate effects on synaptic monoamine levels. Thus, a number of novel agents in development directly target components of this "neuroplasticity hypothesis of depression," including hypothetically overactive glutamatergic neurotransmission and dysfunctional hypothalamic-pituitary-adrenal (HPA) axis functioning.

Glutamate transporters: a key piece in the glutamate puzzle of major depressive disorder

Glutamatergic therapies are emerging as the new path for the treatment of Major Depression Disorder. Recent reports reviewing the use of glutamate activity modulators in the treatment of resistant depression advocate the importance of understanding the alterations of the diverse components of this complex system in mood disorders. In this postmortem study we used in situ hybridization and microarray analysis to evaluate the gene expression of the membrane transporters SLC1A2 and SLCA3 and the vesicular transporter SLCA17A7 in the hippocampus of Major Depressive Disorder (MDD) and Bipolar Disorder (BPD) subjects. Samples from 8 controls, 11 MDD and 6 BPD subjects were processed for in situ hybridization using cRNA probes for SLC1A2, SLC1A3 and SLC17A7. Laser capture microdissection was used to collect tissue from adjacent sections for microarray analysis. The results showed that the expression of the membrane transporters SLC1A2 and SLC1A3 was diminished in the MDD group compared to controls. The expression of the vesicular glutamate transporter SLC17A7 on the other hand was increased in MDD subjects. As for the BPD group, all three transporters showed trends similar to those observed in MDD, but the changes observed did not reach significance. We hypothesize that the decreased expression of the membrane glutamate transporters and the increased expression of the vesicular transporter in the hippocampus would affect the balance of the glutamatergic circuitry of the hippocampus, and that this effect may be a major contributor to depressive symptoms.