Treatment-resistant depression: therapeutic trends, challenges, and future directions

Effectiveness of a Multimodal Digital Psychotherapy Platform for Adult Depression: A Naturalistic Feasibility Study

Background

Although psychotherapy is one of the most efficacious and effective treatments for depression, limited accessibility to trained providers markedly limits access to care. In an attempt to overcome this obstacle, several platforms seeking to provide these services using digital modalities (eg, video, text, and chat) have been developed. However, the use of these modalities individually poses barriers to intervention access and acceptability. Multimodal platforms, comprising those that allow users to select from a number of available modalities, may be able to provide a solution to these concerns.

Objective

We aimed to investigate the preliminary effectiveness of providing psychotherapy through a multimodal digital psychotherapy platform. In addition, we aimed to examine differential responses to intervention by gender, self-reported physical health status, and self-reported financial status, as well as how prior exposure to traditional face-to-face psychotherapy affected the effectiveness of a multimodal digital psychotherapy intervention. Finally, we aimed to examine the dose-response effect.

Methods

Data were collected from a total of 318 active users of BetterHelp, a multimodal digital psychotherapy platform. Data on physical health status, financial status, and prior exposure to psychotherapy were obtained using self-report measures. Effectiveness was determined by the extent of symptom severity change, which was measured using the Patient Health Questionnaire at Time 1 (time of enrollment) and Time 2 (3 months after enrollment). Intervention dosage was measured as the sum of individual therapist-user interactions across modalities.

Results

Depression symptom severity was significantly reduced after the use of the multimodal digital psychotherapy intervention (P<.001). Individuals without prior traditional psychotherapy experience revealed increased improvement after intervention (P=.006). We found no significant dose-response effect of therapy, nor significant differences in outcomes across gender, self-reported financial status, and self-reported physical health status.

Conclusions

Users of BetterHelp experienced significantly reduced depression symptom severity after engaging with the platform. Study findings suggest that this intervention is equally effective across gender, self-reported financial status, and self-reported physical health status and particularly effective for individuals without a history of psychotherapy. Overall, study results suggest that multimodal digital psychotherapy is a potentially effective treatment for adult depression; nevertheless, experimental trials are needed. We discuss directions for future research.

A cross comparison between Ayurvedic etiology of Major Depressive Disorder and bidirectional effect of gut dysregulation

Ayurveda, an Indian medical science has been practiced for thousands of years. What makes Ayurveda relevant today is its subtle understanding of the environment and its focus on the generation of good health through one's own lifestyle choices. The digestive system has long been an area of critical importance within the Ayurvedic system and is only now being acknowledged by modern science as a key component in the regulation of physical and mental well-being. The gut microbiome and enteric nervous system are two particular areas in which the onset of psychiatric disorders, such as depression, have been associated. There are some striking similarities between this biomedical understanding of the gastrointestinal system and the Ayurvedic perspective of disease development. Major Depressive Disorder (MDD) is becoming increasingly linked with gut dysregulation in contemporary literature and is a pathology explored within both the Ayurvedic and Western systems of medicine. This literature review seeks to draw parallels between these two areas of study and highlight the importance of the digestive system when diagnosing and treating MDD.

Linking unfolded protein response to inflammation and depression: potential pathologic and therapeutic implications

Depression is a devastating mental disorder that affects millions of people worldwide. Inflammation has been shown to be a key factor involved in the underlying pathophysiology of depression and has been shown in a substantial proportion of cases of depression. Changes attributed with morphological deformities and immunomodulation in susceptible regions of the depressed brain raised the possibility of altered cellular homeostasis transduced by the intracellular stress response. How emotional stressors can lead to an inflamed brain that directly affects physiology and activity is yet to be fully understood. The unfolded protein response (UPR) has been shown to be active in both models of depression as well as in postmortem brain of depressed individuals. The UPR is the cellular response to stress which results in misfolded proteins. Interestingly, UPR activation is directly linked to both inflammatory cytokine production and Toll-like receptor (TLR) expression. The TLRs are part of the innate immune response which typically reacts to "classic invasions" such as bacteria or viruses as well as trauma. TLRs have also been shown to be upregulated in depression, thus solidifying the connection between inflammation and depression. In this review, we aim to tie the UPR-TLR response and depression, and describe the implications of such an association. We also propose future directions for their role in treatment for depression.

Landmarks of pharmacogenomics and some considerations for clinical practice

Since the completion of the Human Genome Project 28 years ago, myriad genomics applications have risen in areas such as agriculture, livestock, infectious agents, forensics, bioenergy, ancestry, health, disease, and medicine. This was driven partly by the US government's ability to use a unique program to facilitate genome sequencing to the point where the cost of sequencing a whole human genome is not prohibitive. However, application of this knowledge of the double helix twisted DNA at the bedside in psychiatric clinical practice has little to report, despite US Food and Drug Administration (FDA) approval of nearly 40 psychotropic drugs, as well as specific guidelines for their application. Patients with treatment-resistant mental illness, history of unresponsiveness to psychotropic medications, and history or family history of serious adverse effects to psychotropic drugs may qualify for pharmacogenomics (PGx) testing with insurance reimbursement, or a low, out-of-pocket, payment of not greater than US $300. Psychiatric mental health nurse practitioners and providers who utilize PGx will not only improve patient care outcomes, but also contribute to the acceleration of the potential diagnostic and preventive capabilities of PGx testing.

Treatment-resistant depression and peripheral C-reactive protein

BACKGROUND

C-reactive protein (CRP) is a candidate biomarker for major depressive disorder (MDD), but it is unclear how peripheral CRP levels relate to the heterogeneous clinical phenotypes of the disorder.AimTo explore CRP in MDD and its phenotypic associations.

METHOD

We recruited 102 treatment-resistant patients with MDD currently experiencing depression, 48 treatment-responsive patients with MDD not currently experiencing depression, 48 patients with depression who were not receiving medication and 54 healthy volunteers. High-sensitivity CRP in peripheral venous blood, body mass index (BMI) and questionnaire assessments of depression, anxiety and childhood trauma were measured. Group differences in CRP were estimated, and partial least squares (PLS) analysis explored the relationships between CRP and specific clinical phenotypes.

RESULTS

Compared with healthy volunteers, BMI-corrected CRP was significantly elevated in the treatment-resistant group (P = 0.007; Cohen's d = 0.47); but not significantly so in the treatment-responsive (d = 0.29) and untreated (d = 0.18) groups. PLS yielded an optimal two-factor solution that accounted for 34.7% of variation in clinical measures and for 36.0% of variation in CRP. Clinical phenotypes most strongly associated with CRP and heavily weighted on the first PLS component were vegetative depressive symptoms, BMI, state anxiety and feeling unloved as a child or wishing for a different childhood.

CONCLUSIONS

CRP was elevated in patients with MDD, and more so in treatment-resistant patients. Other phenotypes associated with elevated CRP included childhood adversity and specific depressive and anxious symptoms. We suggest that patients with MDD stratified for proinflammatory biomarkers, like CRP, have a distinctive clinical profile that might be responsive to second-line treatment with anti-inflammatory drugs.Declaration of interestS.R.C. consults for Cambridge Cognition and Shire; and his input in this project was funded by a Wellcome Trust Clinical Fellowship (110049/Z/15/Z). E.T.B. is employed half time by the University of Cambridge and half time by GlaxoSmithKline; he holds stock in GlaxoSmithKline. In the past 3 years, P.J.C. has served on an advisory board for Lundbeck. N.A.H. consults for GlaxoSmithKline. P.d.B., D.N.C.J. and W.C.D. are employees of Janssen Research &amp; Development, LLC., of Johnson &amp; Johnson, and hold stock in Johnson &amp; Johnson. The other authors report no financial disclosures or potential conflicts of interest.

Enrichment of pathogenic variants in genes associated with inborn errors of metabolism in psychiatric populations

Many genetic conditions can mimic mental health disorders, with psychiatric symptoms that are difficult to treat with standard psychotropic medications. This study tests the hypothesis that psychiatric populations are enriched for pathogenic variants associated with selected inborn errors of metabolism (IEMs). Using next-generation sequencing, 2046 psychiatric patients were screened for pathogenic variants in genes associated with four IEMs, Niemann-Pick disease type C (NPC), Wilson disease (WD), homocystinuria (HOM), and acute intermittent porphyria (AIP). Among the 2046 cases, carrier rates of 0.83, 0.98, and 0.20%, for NPC, WD and HOM, and affected rates of 0.10 and 0.24% for NPC and AIP were seen, respectively. An enrichment of known and predicted pathogenic variants in the genes associated with NPC and AIP was found in the psychiatric cohort and especially in schizophrenia patients. The results of this study support that pathogenic variants in genes associated with IEMs are enriched in psychiatric populations. Underlying undiagnosed IEMs could account for the psychiatric symptomatology in a subset of psychiatric patients. Further studies are warranted to investigate the possibility that carriers for IEMs may have an increased risk for psychiatric disorders, particularly in the context of poor treatment response.

C-reactive protein and its association with depression in patients receiving treatment for metastatic lung cancer

BACKGROUND

Depression is highly prevalent in lung cancer. Although there is a known association between inflammation and depression, this relationship has not been examined in patients with lung cancer who undergo treatment with immune and other targeted drug therapies. Peripheral blood C-reactive protein (CRP), a marker of systemic inflammation, may help identify metastatic lung cancer patients with inflammation-associated depression.

METHOD

Patients with metastatic lung cancer undergoing treatment were evaluated for depression using the Hospital Anxiety and Depression Scale (HADS). Inflammation (CRP and CRP cutoffs ≥1 and ≥3 mg/mL) and demographic and treatment variables were analyzed for association with depression.

RESULTS

One hundred nine consecutive participants exhibited an average plasma CRP concentration of 1.79 mg/mL (median, 0.75 mg/mL [standard deviation, 2.5 mg/mL), and 20.7% had a CRP concentration of ≥3.0 mg/mL; 23.9% met depression screening criteria (HADS ≥8). A log transformation of CRP was significantly correlated with depression severity (r = 0.47, P < .001). CRP was the only covariate to predict depression severity (P = .008) in a multivariate model including lung cancer disease subtype and type of systemic treatment. Receiver operating characteristic analysis indicated that CRP had moderate predictive accuracy in identifying elevated depression (area under the curve = 0.74). A cutoff of CRP ≥3.0 generated high specificity (88%) but identified only 50% of those with elevated depression.

CONCLUSION

Elevated CRP is associated with depression in patients with metastatic lung cancer. Thus, CRP may identify a subset of lung cancer patients with inflammation-induced depression and may be useful in predicting response to treatments that target inflammation or its downstream mediators on the brain.

A brief history of antidepressant drug development: from tricyclics to beyond ketamine

OBJECTIVE

Although monoaminergic-targeted drugs have prompted great advances in the development of treatments for depression, the need for new options persists, since these drugs still have a delayed clinical effect and most patients do not respond properly to them. Recently, the observation of the antidepressant effects of ketamine brought on a new wave of studies regarding the comprehension of the neurobiology of depression and the development of new and more effective antidepressant drugs.

METHODS

Thus, in this paper, we present a historical review of the development of monoaminergic antidepressant drugs and the role of ketamine as the introductory agent of a new era in the research of the neurobiology of depression.

RESULTS

Firstly, we review how the pharmacological treatment for major depression started, and we point out the main drugs discovered, the researchers involved, and how the studies developed have contributed to the understanding of the neurobiology of depression. Secondly, the major problems regarding the clinical efficacy and acceptance of these drugs are discussed, and the introduction of the glutamatergic system as a target for antidepressant drugs is presented. Finally, we review how ketamine revealed itself as an exciting option towards obtaining pharmacological agents to treat depression, through the understanding of biological markers.DiscussionKetamine contributed to confirm that different targets of the glutamatergic system and neurotrophic pathways are strictly related to the neurobiology of depression. There are several antidepressant drugs based on ketamine's mechanism of action already in the pipeline, and glutamatergic-targeted antidepressants may be on the market in the near future.

Cognitive function of patients with treatment-resistant depression after a single low dose of ketamine infusion

BACKGROUND

Clinical and animal studies have reported conflicting results regarding the effect of ketamine on cognitive function, although increasing evidence supports a rapid and sustained antidepressant effect of a subanesthetic dose of ketamine infusion for patients with treatment-resistant depression (TRD). However, the cognitive function before and after ketamine infusion was rarely investigated in patients with TRD.

METHODS

A total of 71 adult patients with TRD were enrolled and randomized to 0.5-mg/kg ketamine, 0.2-mg/kg ketamine, or normal saline infusion groups. Depressive symptoms were measured using the Hamilton Depression Rating Scale at baseline and at different time points post ketamine infusion. Cognitive function was evaluated using working memory and go/no-go tasks at baseline, Day 3, and Day 14 post ketamine infusion.

RESULTS

A single low dose of ketamine infusion did not impair the cognitive function of patients with TRD. The paired t test revealed that patients with TRD receiving 0.5 mg/kg of ketamine infusion exhibited a slight improvement in sustained attention and response control measured using the go/no-go task at Day 14 post ketamine infusion. A significant association was also observed between depressive symptoms and cognitive function changes at Day 3 in the 0.5-mg/kg ketamine infusion group.

DISCUSSION

A 0.5 mg/kg dose of ketamine infusion was not harmful, but slightly beneficial, for the cognitive function of patients with TRD. Additional studies are necessary to elucidate the effects of repeated ketamine infusion on cognitive function.

Hospital production cost of transcranial direct current stimulation (tDCS) in the treatment of depression

OBJECTIVES

Due to its ease of use, tolerance, and cost of acquisition, transcranial direct current stimulation (tDCS) could constitute a credible therapeutic option for non-resistant depression in primary care, when combined with drug management. This indication has yet to receive official recognition in France. The objective of this study is to evaluate the production cost of tDCS for the treatment of depression in hospitals, under realistic conditions.

METHODS

The methodology adopted is based on cost accounting and was validated by a multidisciplinary working group. It includes equipment, staff, and structural costs to obtain the most realistic estimate possible. We first estimated the cost of producing a tDCS session, based on our annual activity objective, and then estimated the cost of a 15-session treatment program. This was followed up with a sensitivity analysis applying appropriate parameters.

RESULTS

The hospital production cost of a tDCS depression treatment program for a single patient was estimated at €1555.60 euros: €99 in equipment costs, €1076.95 in staff costs, and €379.65 in structural costs.

CONCLUSION

This cost analysis should make it possible to draw up pricing proposals in compliance with regulations and health policy choices and to develop health-economic studies. This would ultimately lead to official recognition of tDCS treatment for depression in France and pave the way for studying various scenarios of coverage by the French national health insurance system.

Humanistic outcomes in treatment resistant depression: a secondary analysis of the STAR*D study

BACKGROUND

In the Sequenced Treatment Alternatives to Relieve Depression (STAR*D) study, a third of patients did not achieve remission or adequate response after two treatment trials, fulfilling requirements for treatment resistant depression (TRD). The present study is a secondary analysis of the STAR*D data conducted to compare the humanistic outcomes in patients with TRD and non-TRD MDD.

METHODS

Patients with major depressive disorder who entered level 3 of the STAR*D were included in the TRD group, while patients who responded to treatment and entered follow-up from level 1 or 2 were included in the non-TRD group. The first visit in level 1 was used for baseline assessments. The time-point of assessments for comparison was the first visit in level 3 for TRD patients (median day: 141), and the visit closest to 141 ± 60 days from baseline for non-TRD patients. Outcomes were assessed by the 12-item Short Form Health Survey (SF12), 16-item Quality of Life Enjoyment and Satisfaction Questionnaire (Q-LES-Q), Work and Social Adjustment Scale (WSAS), and Work Productivity and Activity Impairment scale (WPAI). Scores were compared in a linear model with adjustment for covariates including age, gender, and depression severity measured by the 17-item Hamilton Rating Scale for Depression (HDRS17) and Quick Inventory of Depressive Symptomatology (QIDS).

RESULTS

A total of 2467 (TRD: 377; non-TRD: 2090) patients were studied. TRD patients were slightly older (mean age 44 vs 42 years), had a higher proportion of men (49% vs 37%, p < .0001), and baseline depression severity (HDRS17: 24.4 vs 22.0, p < .0001) vs non-TRD patients. During follow-up, TRD patients had lower health-related quality of life (HRQOL) scores on mental (30 vs 45.7) and physical components (47.7 vs 48.9) of the SF12, and lower Q-LES-Q scores (43.6 vs 63.7), greater functional and work impairments and productivity loss vs non-TRD patients (all p < 0.05).

CONCLUSION

Patients with TRD had worse HRQOL, work productivity, and social functioning than the non-TRD patients.

Putative Inflammatory Sensitive Mechanisms Underlying Risk or Resilience to Social Stress

It has been well recognized that exposure to stress can lead to the onset of psychosocial disorders such as depression. While there are a number of antidepressant therapies currently available and despite producing immediate neurochemical alterations, they require weeks of continuous use in order to exhibit antidepressant efficacy. Moreover, up to 30% of patients do not respond to typical antidepressants, suggesting that our understanding of the pathophysiology underlying stress-induced depression is still limited. In recent years inflammation has become a major focus in the study of depression as several clinical and preclinical studies have demonstrated that peripheral and central inflammatory mediators, including interleukin (IL)-1β, are elevated in depressed patients. Moreover, it has been suggested that inflammation and particularly neuroinflammation may be a direct and immediate link in the emergence of stress-induced depression due to the broad neural and glial effects that are elicited by proinflammatory cytokines. Importantly, individual differences in inflammatory reactivity may further explain why certain individuals exhibit differing susceptibility to the consequences of stress. In this review article, we discuss sources of individual differences such as age, sex and coping mechanisms that are likely sources of distinct changes in stress-induced neuroimmune factors and highlight putative sources of exaggerated neuroinflammation in susceptible individuals. Furthermore, we review the current literature of specific neural and glial mechanisms that are regulated by stress and inflammation including mitochondrial function, oxidative stress and mechanisms of glutamate excitotoxicity. Taken together, the impetus for this review is to move towards a better understanding of mechanisms regulated by inflammatory cytokines and chemokines that are capable of contributing to the emergence of depressive-like behaviors in susceptible individuals.

More Realistic Forecasting of Future Life Events After Psilocybin for Treatment-Resistant Depression

Background: Evidence suggests that classical psychedelics can promote enduring changes in personality, attitudes and optimism, as well as improvements in mental health outcomes. Aim: To investigate the effects of a composite intervention, involving psilocybin, on pessimism biases in patients with treatment-resistant depression (TRD). Methods: Patients with TRD (n = 15) and matched, untreated non-depressed controls (n = 15) performed the Prediction Of Future Life Events (POFLE) task. The POFLE task requires participants to predict the likelihood of certain life events occurring within a 30-day period, after which the actual rate of event occurrence is reported; this gives an index of potential pessimism versus optimism bias. Psilocybin was administered in two oral dosing sessions (10 and 25 mg) one week apart. Main outcome measures were collected at baseline and one week after the second dosing session. Results: Patients showed a significant pessimism bias at baseline [t(14) = -3.260, p = 0.006; 95% CI (-0.16, -0.03), g = 1.1] which was related to the severity of their depressive symptoms (r_s = -0.55, p = 0.017). One week after psilocybin treatment, this bias was significantly decreased [t(14) = -2.714, p = 0.017; 95% CI (-0.21, -0.02), g = 0.7] and depressive symptoms were greatly improved [t(14) = 7.900, p < 0.001; 95% CI (16.17, 28.23), g = 1.9]; moreover, the magnitude of change in both variables was significantly correlated (r = -0.57, p = 0.014). Importantly, post treatment, patients became significantly more accurate at predicting the occurrence of future life events [t(14) = 1.857, p = 0.042; 95% CI (-0.01, 0.12), g = 0.6] whereas no such change was observed in the control subjects. Conclusion: These findings suggest that psilocybin with psychological support might correct pessimism biases in TRD, enabling a more positive and accurate outlook.

Comparative study of esketamine and racemic ketamine in treatment-resistant depression: Protocol for a non-inferiority clinical trial

INTRODUCTION

The use of ketamine as an option in the treatment of depressive disorder is growing rapidly, supported by numerous clinical trials attesting its efficacy and safety. Esketamine, the S (+) enantiomer of ketamine, is the most widely used form in the anesthetic environment in some countries, and new studies have shown that it may also be effective in depression and with better tolerability. However, no study so far has directly compared esketamine with racemic ketamine. Here we propose a protocol of a clinical trial to evaluate esketamine as a noninferior medication when compared to ketamine in the treatment of patients with treatment-resistant depression.

METHODS/DESIGN

This study protocol is for a randomized, controlled, double-blind noninferiority clinical trial. Subjects will be 18 years or older, with major depression characterized as treatment-resistant. Participants will receive a single infusion of either esketamine (0.25 mg/kg) or ketamine (0.5 mg/kg) over 40 minutes. The primary outcome will be the difference in remission rates between the 2 treatment arms at 24 and 72 hours after drug infusion. Secondary outcomes will include other timepoints, measurements of cognition, dissociation, and blood biomarkers.

DISCUSSION

A head-to-head study is the best way to evaluate whether the esketamine is in fact comparable to the racemic ketamine in terms of both efficacy and safety, and, if positive, it would be an initial step to increase the access to that type of treatment worldwide.

ETHICS AND DISSEMINATION

The study was approved by the local Institutional Review Board (University Hospital Professor Edgard Santos-Federal University of Bahia-Number: 46657415.0.0000.0049). Subjects will only participate after voluntarily agreeing and signing the Informed Consent Form. The study findings will be published in peer-reviewed journals and presented at national and international conferences.

TRIAL REGISTRATION

This trial has been registered in the Japan Primary Registries Network (JPRN): UMIN000032355, which is affiliated with the World Health Organization.

Changes in healthcare resource use and costs associated with early versus delayed initiation of atypical antipsychotic adjunctive treatment in major depressive disorder

AIMS

The study compared all-cause and major depressive disorder (MDD)-related healthcare resource use (HRU) and costs in patients with MDD treated with atypical antipsychotic (AAP) adjunctive therapy early or later in treatment.

MATERIALS AND METHODS

Adults with MDD and antidepressant treatment (ADT) who newly initiated adjunctive aripiprazole, brexpiprazole, lurasidone, or quetiapine between October 1, 2014 and September 30, 2015 were identified in the IQVIA Real-World Data Adjudicated Claims database; the index date was the date of the first AAP claim. Patients were stratified into three cohorts: AAP initiated in the first year (Y1); in the second year (Y2); and more than 2 years (Y3) of first ADT use. Within each cohort, HRU and costs were compared between the 12 months before and after the index date. Pre-post changes in HRU and costs were then compared between cohorts.

RESULTS

Five hundred and six (36.7%) patients were categorized as Y1; 252 (18.3%) as Y2; and 622 (45.1%) as Y3. AAP use was associated with significantly decreased rates of all-cause and MDD-related hospitalization and emergency department visits, and increased rates of pharmacy fills and physician office visits; and the magnitude of changes was largest in cohort Y1. Cohort Y1 had the largest reductions in mean (±SD) all-cause medical costs per patient (-$10,496 ± $85,022, p = .015) compared to Y2 (-$2,474 ± $85,022, p = .572) and Y3 (-$472 ± $31,334, p = .823), mainly due to the reduction in hospitalization. After adjusting for differences in baseline characteristics, the largest reductions in hospitalization and medical costs were observed in cohort Y1. Similar increases in all-cause pharmacy costs were seen in all cohorts. A similar trend in costs was observed in MDD-related healthcare services.

LIMITATIONS AND CONCLUSIONS

AAP treatment was associated with reductions in all-cause and MDD-related medical costs, primarily in decreased hospitalization. The reductions were largest among patients who initiated treatment in the first year.

Profiling changes in cortical astroglial cells following chronic stress

Recent studies have suggested that cortical astroglia play an important role in depressive-like behaviors. Potential astroglial contributions have been proposed based on their known neuroplastic functions, such as glutamate recycling and synaptic plasticity. However, the specific mechanisms by which astroglial cells may contribute or protect against a depressive phenotype remain unknown. To delineate astroglial changes that accompany depressive-like behavior, we used astroglial-specific bacTRAP mice exposed to chronic variable stress (CVS) and profiled the astroglial translatome using translating ribosome affinity purification (TRAP) in conjunction with RNAseq. As expected, CVS significantly increased anxiety- and depressive-like behaviors and corticosterone levels and decreased GFAP expression in astroglia, although this did not reflect a change in the total number of astroglial cells. TRAPseq results showed that CVS decreased genes associated with astroglial plasticity: RhoGTPases, growth factor signaling, and transcription regulation, and increased genes associated with the formation of extracellular matrices such as perineuronal nets (PNNs). PNNs inhibit neuroplasticity and astroglia contribute to the formation, organization, and maintenance of PNNs. To validate our TRAPseq findings, we showed an increase in PNNs following CVS. Degradation of PNNs in the prefrontal cortex of mice exposed to CVS reversed the CVS-induced behavioral phenotype in the forced swim test. These data lend further support to the neuroplasticity hypothesis of depressive behaviors and, in particular, extend this hypothesis beyond neuronal plasticity to include an overall decrease in genes associated with cortical astroglial plasticity following CVS. Further studies will be needed to assess the antidepressant potential of directly targeting astroglial cell function in models of depression.

EEG gamma synchronization is associated with response to paroxetine treatment

BACKGROUND

Resistance to medication is a significant problem in psychiatric practice, and effective methods for predicting response are needed to optimize treatment efficacy and limit morbidity. Gamma oscillations are considered as an index of the brain's general cognitive activity; however, the role of gamma oscillations in disease has not been studied sufficiently.

AIM

This study aimed to determine if gamma power during rest can be used to predict response to anti-depressant medication treatment.

METHOD

Hamilton Depression Rating Scale (HDRS) score and resting state gamma power was measured in 18 medication-free patients during an episode of major depression. After 6 weeks of paroxetine monotherapy HDRS was administered again.

RESULTS

Baseline gamma power at frontal, central and temporal electrodes before treatment was significantly related to post-treatment change in HDRS scores.

CONCLUSION

The results indicate that gamma oscillations could be considered a marker of response to paroxetine treatment in patients with major depression.

Finding factors that predict treatment-resistant depression: Results of a cohort study

BACKGROUND

Treatment for depressive disorders often requires subsequent interventions. Patients who do not respond to antidepressants have treatment-resistant depression (TRD). Predicting who will develop TRD may help healthcare providers make more effective treatment decisions. We sought to identify factors that predict TRD in a real-world setting using claims databases.

METHODS

A retrospective cohort study was conducted in a US claims database of adult subjects with newly diagnosed and treated depression with no mania, dementia, and psychosis. The index date was the date of antidepressant dispensing. The outcome was TRD, defined as having at least three distinct antidepressants or one antidepressant and one antipsychotic within 1 year after the index date. Predictors were age, gender, medical conditions, medications, and procedures 1 year before the index date.

RESULTS

Of 230,801 included patients, 10.4% developed TRD within 1 year. TRD patients at baseline were younger; 10.87% were between 18 and 19 years old versus 7.64% in the no-TRD group, risk ratio (RR) = 1.42 (95% confidence interval [CI] 1.37-1.48). TRD patients were more likely to have an anxiety disorder at baseline than non-TRD patients, RR = 1.38 (95% CI 1.35-1.14). At 3.68, fatigue had the highest RR (95% CI 3.18-4.25). TRD patients had substance use disorders, psychiatric conditions, insomnia, and pain more often at baseline than non-TRD patients.

CONCLUSION

Ten percent of subjects newly diagnosed and treated for depression developed TRD within a year. They were younger and suffered more frequently from fatigue, substance use disorders, anxiety, psychiatric conditions, insomnia, and pain than non-TRD patients.

Delayed increase of thrombocyte levels after a single sub-anesthetic dose of ketamine - A randomized trial

Recently, ketamine has been investigated as a potential antidepressant option for treatment resistant depression. Unlike traditional drugs, it yields immediate effects, most likely via increased glutamatergic transmission and synaptic plasticity. However, ketamine administration in humans is systemic and its long-term impact on blood parameters has not yet been described in clinical studies. Here we investigated potential sustained effects of ketamine administration (0.5 mg/kg ketamine racemate) on hematological and biochemical values in plasma and serum in a randomized double-blinded study. 80 healthy young participants were included and whole blood samples were collected 5 days before, and 14 days after the infusion. To assess the group effect, repeated measure analyses of co-variance (rmANCOVA) were conducted for the following blood parameters: levels of sodium, potassium, calcium, hemoglobin and number of erythrocytes, lymphocytes, and thrombocytes. RmANCOVA revealed a significant time by treatment effect on thrombocyte levels (F_{1, 74} = 13.54, p < 0.001, eta = 0.155), driven by an increase in the ketamine group (paired t-test, t = -3.51, df = 38, p = 0.001). Specificity of thrombocyte effect was confirmed by logistic regression, and in addition, no other coagulation parameters showed significant interaction. Moreover, the relative increase in the ketamine group was stable across sexes and not predicted by age, BMI, smoking, alcohol or drug use, and contraception. Our results describe aftereffects of sub-anesthetic ketamine administration on blood coagulation parameters, which should be considered especially when targeting psychiatric populations with relevant clinical comorbidities.

Toward Serotonin Fluorescent False Neurotransmitters: Development of Fluorescent Dual Serotonin and Vesicular Monoamine Transporter Substrates for Visualizing Serotonin Neurons

Ongoing efforts in our laboratories focus on design of optical reporters known as fluorescent false neurotransmitters (FFNs) that enable the visualization of uptake into, packaging within, and release from individual monoaminergic neurons and presynaptic sites in the brain. Here, we introduce the molecular probe FFN246 as an expansion of the FFN platform to the serotonergic system. Combining the acridone fluorophore with the ethylamine recognition element of serotonin, we identified FFN54 and FFN246 as substrates for both the serotonin transporter and the vesicular monoamine transporter 2 (VMAT2). A systematic structure-activity study revealed the basic structural chemotype of aminoalkyl acridones required for serotonin transporter (SERT) activity and enabled lowering the background labeling of these probes while maintaining SERT activity, which proved essential for obtaining sufficient signal in the brain tissue (FFN246). We demonstrate the utility of FFN246 for direct examination of SERT activity and SERT inhibitors in 96-well cell culture assays, as well as specific labeling of serotonergic neurons of the dorsal raphe nucleus in the living tissue of acute mouse brain slices. While we found only minor FFN246 accumulation in serotonergic axons in murine brain tissue, FFN246 effectively traces serotonin uptake and packaging in the soma of serotonergic neurons with improved photophysical properties and loading parameters compared to known serotonin-based fluorescent tracers.

Hypobaric hypoxia exposure in rats differentially alters antidepressant efficacy of the selective serotonin reuptake inhibitors fluoxetine, paroxetine, escitalopram and sertraline

Treatment-resistant depression, a chronic condition that affects 30% of depressed patients on antidepressants, is highly linked to suicidal behavior. Chronic hypoxia exposure via living at altitude (hypobaric hypoxia) or with chronic hypoxic diseases is demographically linked to increased risk for depression and suicide. We previously demonstrated that housing rats at altitude for a week incrementally increases depression-like behavior in the forced swim test (FST) in females, but not males. In animal models, high altitude exposure reduces brain serotonin, and selective serotonin reuptake inhibitors (SSRIs) can lose efficacy when brain serotonin levels are low. To address whether residence at moderate altitude is detrimental to SSRI function, we examined SSRI efficacy in the FST after a week of housing rats at altitudes of 4500 ft. or 10,000 ft. as compared to at sea level. In females, the tricyclic antidepressant desipramine (positive control) functioned well in all groups, increasing latency to immobility and decreasing immobility, by increasing climbing. However, the SSRIs fluoxetine, paroxetine and escitalopram were ineffective in females in all groups: only paroxetine improved swimming in the FST as expected of a SSRI, while all three unexpectedly reduced climbing. Fluoxetine was also ineffective in male rats. Sertraline was the only SSRI with antidepressant efficacy at altitude in both females and males, increasing swimming, climbing and latency to immobility, and reducing immobility. Hypobaric hypoxia thus appears to be detrimental to efficacy of the SSRIs fluoxetine, paroxetine and escitalopram, but not of sertraline. Unlike the other SSRIs, sertraline can improve both serotonergic and dopaminergic transmission, and may be less impacted by a hypoxia-induced serotonin deficit. A targeted approach may thus be necessary for successful antidepressant treatment in patients with depression who live at altitude or with chronic hypoxic diseases, and that sertraline may be the SSRI of choice for prescription for this population.

The MAKE Biomarker Discovery for Enhancing anTidepressant Treatment Effect and Response (MAKE BETTER) Study: Design and Methodology

OBJECTIVE

Depression is associated with a major disease burden, and many individuals suffer from depressive symptoms due to an insufficient response to ostensibly adequate antidepressant treatment. Therefore, it is important to identify reliable treatment response predictors for use in developing personalized treatment strategies.

METHODS

The MAKE Biomarker discovery for Enhancing anTidepressant Treatment Effect and Response (MAKE BETTER) study was performed to identify predictors of antidepressant response using a 2-year naturalistic prospective design. Participants in the MAKE BETTER study were consecutively recruited from patients who visited the Psychiatry Department of Chonnam National University Hospital, Gwangju, South Korea for treatment of a depressive disorder. Data on demographic and clinical characteristics, genetic markers measured by whole-exome sequencing, and blood markers were obtained. The types and doses of antidepressants were determined based on the clinical judgment of the psychiatrist, and the treatment outcomes (e.g., depressive and other psychiatric symptoms and issues related to safety) were assessed.

RESULTS

We will be able to use the data collected in this study to develop a treatment-response prediction index composed of biomarkers.

CONCLUSION

The MAKE BETTER study will provide an empirical basis for a personalized medicine approach to depression by enabling the prediction of antidepressant treatment response according the characteristics of each patient. It will thereby support evidence-based decision-making that decreases the use of a trial-and-error approach to the treatment of depressive disorders.

Pharmacodynamic and pharmacokinetic evaluation of buprenorphine + samidorphan for the treatment of major depressive disorder

INTRODUCTION

Treatment resistant depression (TRD) represents approximately 20% of all individuals receiving care for major depressive disorder. The opioidergic system is identified as a novel target which hitherto has not been sufficiently investigated in adults with TRD. The combination product buprenorphine + samidorphan is an opioid modulatory agent which has demonstrated replicated evidence of efficacy in TRD without abuse liability. Areas covered: Databases Pubmed, Google Scholar and clinicaltrials.gov were searched from inception through December 2017 for clinical trial information, pharmacokinetics, and pharmacodynamics of buprenorphine + samidorphan. Herein we provide a summary of the available information. Eight clinical trials were identified for inclusion, of the eight trials, five trials had available results and are included in detail in our review. Expert opinion: Buprenorphine + samidorphan has demonstrated efficacy in TRD. Extant evidence surrounding the safety and tolerability profile of buprenorphine + samidorphan does not identify any significant safety concerns. Additional studies are needed in order to assess the long-term safety and efficacy of this product.

The molecular aspects of oxidative & nitrosative stress and the tryptophan catabolites pathway (TRYCATs) as potential causes of depression

Depression is the most common mental disorder in the world. It is estimated that 350 million people suffer from depression worldwide. Depressive disorders will have become the second most frequent health problem globally by the year 2020, just behind ischemic heart disease. The causes of depressive disorders are not fully known. Previous studies showed that impaired tryptophan catabolites pathway, oxidative and nitrosative stress may play an important role in the pathogenesis of depression. Patients with depression have lower plasma levels of superoxide dismutase and glutathione peroxidise in comparison to controls. Moreover, depressed patients are characterized by decreased plasma levels of zinc, coenzyme Q10, albumin, uric acid, vitamin E and glutathione. Abnormal nitric oxidative production and nitric oxide synthase activity are also associated with depression. A dysfunction of the tryptophan catabolites pathway, indicated by increased levels of tryptophan 2,3-dioxygenase and indoleamine 2,3-dioxygenase, is also involved in the development of depression. Furthermore, increased levels of kynurenine and quinolinic acid might cause depression. Moreover, studies to date indicate that 8-oxyguanine, malondialdehyde, and 8-iso-prostaglandin F2α may serve as possible biomarkers. Additionally, regulation of defective mechanisms may provide a promising direction for the development of new and effective therapies.

Estimating Prevalence and Healthcare Utilization for Treatment-Resistant Depression in Japan: A Retrospective Claims Database Study

BACKGROUND

Major depressive disorders (MDDs) including treatment-resistant depression (TRD) are common disabling conditions, but data on their epidemiology in Japan are limited. This study investigated the incidence, epidemiology, and direct medical costs of TRD and pharmaceutically-treated depression (PTD) in Japan to increase our health economic understanding of this phenotype of MDD.

METHODS

A retrospective cohort study from a private health insurance claims database estimated the 1-year incidence of PTD and TRD and described the health services used and direct medical costs associated with these conditions.

RESULTS

In the year from 1 April 2012 through 31 March 2013, we identified 1143 incident PTD cases among 98,552 eligible subjects, i.e. 11.59 cases/1000 patient-years. Of the PTD patients, 51.4% were women. Within the 1-year observation interval 137 patients failed more than two antidepressive treatment approaches and thus developed TRD. Though co-morbid conditions and age were similar among PTD and TRD patients, medical costs per patient (patient-year) during their treatment intervals were 1.01 million JPY (0. 540 million JPY) in the TRD population and 0.643 JPY million JPY (0.645 million JPY) in the PTD population who did not convert into TRD.

CONCLUSIONS

This study describes the PTD and TRD patient populations in a large claims database in Japan and highlights an unmet medical need for the treatment of TRD to provide better preventative measures and interventions for the treatment of depression.

Therapeutic Strategies for Treatment of Inflammation-related Depression

BACKGROUND

Mounting evidence demonstrates enhanced systemic levels of inflammatory mediators in depression, indicating that inflammation may play a role in the etiology and course of mood disorders. Indeed, proinflammatory cytokines induce a behavioral state of conservation- withdrawal resembling human depression, characterized by negative mood, fatigue, anhedonia, psychomotor retardation, loss of appetite, and cognitive deficits. Neuroinflammation also contributes to non-responsiveness to current antidepressant (AD) therapies. Namely, response to conventional AD medications is associated with a decrease in inflammatory biomarkers, whereas resistance to treatment is accompanied by increased inflammation.

METHODS

In this review, we will discuss the utility and shortcomings of pharmacologic AD treatment strategies focused on inflammatory pathways, applied alone or as an adjuvant component to current AD therapies.

RESULTS

Mechanisms of cytokine actions on behavior involve activation of inflammatory pathways in the brain, resulting in changes of neurotransmitter metabolism, neuroendocrine function, and neuronal plasticity. Selective serotonin reuptake inhibitors exhibit the most beneficial effects in restraining the inflammation markers in depression. Different anti-inflammatory agents exhibit AD effects via modulating neurotransmitter systems, neuroplasticity markers and glucocorticoid receptor signaling. Anti-inflammatory add-on therapy in depression highlights such treatment as a candidate for enhancement strategy in patients with moderate-to-severe depression.

CONCLUSION

The interactions between the immune system and CNS are not only involved in shaping behavior, but also in responding to therapeutics. Even though, substantial evidence from animal and human research support a beneficial effect of anti-inflammatory add-on therapy in depression, further research with special attention on safety, particularly during prolonged periods of antiinflammatory co-treatments, is required.

Sesquiterpenoids from the Root of Panax ginseng Attenuates Lipopolysaccharide-Induced Depressive-Like Behavior through the Brain-Derived Neurotrophic Factor/Tropomyosin-Related Kinase B and Sirtuin Type 1/Nuclear Factor-κB Signaling Pathways

The previous study indicated sesquiterpenoids from the root of Panax ginseng (SPG) exhibited a significant antidepressant-like effect, which might be mediated by the modification of the dopaminergic, GABAergic, and glutamatergic systems. This study was to investigate antidepressant effects and mechanisms on the lipopolysaccharide (LPS)-induced depression-like behavior of SPG. In the tail suspension test (TST) and forced swimming test (FST), SPG (0.25 and 1 mg/kg, i.g.) and fluoxetine (20 mg/kg, i.p.) effectively reduced the immobility time. SPG treatment significantly reduced serum levels of IL-6 and TNF-α and increased suppressed superoxide dismutase (SOD) activity in the hippocampus. In addition, SPG effectively upregulated the brain-derived neurotrophic factor (BDNF), tropomyosin-related kinase B (TrkB), and sirtuin type 1 (Sirt 1) expression in the hippocampus and downregulated the inhibitor of κB-α (IκB-α) and nuclear factor-κB (NF-κB) phosphorylation. These results suggested that SPG exhibited an antidepressant-like effect through the BDNF/TrkB and Sirt 1/NF-κB signaling pathways.

Cytokine alterations and cognitive impairment in major depressive disorder: From putative mechanisms to novel treatment targets

Overwhelming evidence indicates the involvement of immune-inflammatory processes in the pathophysiology of major depressive disorder (MDD). Peripheral cytokine alterations serve as one of most consistently reported indices of subthreshold inflammatory state observed in MDD. Although cytokines cannot pass directly through the blood-brain barrier, a number of transport mechanisms have been reported. In addition, peripheral cytokines may impact central nervous system via downstream effectors of their biological activity. Animal model studies have provided evidence that cytokines might impact cognitive performance through direct and indirect effects on long-term potentiation, neurogenesis and synaptic plasticity. Therefore, it has been hypothesized that cytokine alterations might contribute to cognitive impairment that is widely observed in MDD and persists beyond episodes of acute relapse in the majority of patients. Although several studies have provided that peripheral cytokine alterations might be related to cognitive deficits in patients with MDD, the quality of evidence still leaves much to be desired due to methodological heterogeneity and limitations. In this article, we provide an overview of studies investigating the association between peripheral cytokine alterations and cognitive performance in MDD, discuss underlying mechanisms and neural substrates. Finally, we propose possible treatment targets related to cytokine alterations taking into account existing evidence for antidepressant efficacy of anti-inflammatory pharmacological treatment modalities.

HCN2 channels in the ventral tegmental area regulate behavioral responses to chronic stress

Dopamine neurons in the ventral tegmental area (VTA) are powerful regulators of depression-related behavior. Dopamine neuron activity is altered in chronic stress-based models of depression, but the underlying mechanisms remain incompletely understood. Here, we show that mice subject to chronic mild unpredictable stress (CMS) exhibit anxiety- and depressive-like behavior, which was associated with decreased VTA dopamine neuron firing in vivo and ex vivo. Dopamine neuron firing is governed by voltage-gated ion channels, in particular hyperpolarization-activated cyclic nucleotide-gated (HCN) channels. Following CMS, HCN-mediated currents were decreased in nucleus accumbens-projecting VTA dopamine neurons. Furthermore, shRNA-mediated HCN2 knockdown in the VTA was sufficient to recapitulate CMS-induced depressive- and anxiety-like behavior in stress-naïve mice, whereas VTA HCN2 overexpression largely prevented CMS-induced behavioral deficits. Together, these results reveal a critical role for HCN2 in regulating VTA dopamine neuronal activity and depressive-related behaviors.

Neural basis of major depressive disorder: Beyond monoamine hypothesis

The monoamine hypothesis has been accepted as the most common hypothesis of major depressive disorder (MDD) for a long period because of its simplicity and understandability. Actually, most currently used antidepressants have been considered to act based on the monoamine hypothesis. However, an important problem of the monoamine hypothesis has been pointed out as follows: it fails to explain the latency of response to antidepressants. In addition, many patients with MDD have remained refractory to currently used antidepressants. Therefore, monoamine-alternate hypotheses are required to explain the latency of response to antidepressants. Such hypotheses have been expected to contribute to identifying hopeful new therapeutic targets for MDD. Past studies have revealed that the volume of the hippocampus is decreased in patients with MDD, which is likely caused by the failure of the hypothalamic-pituitary-adrenal axis and following elevation of glucocorticoids. Two hypotheses have been proposed to explain the volume of the hippocampus: (i) the neuroplasticity hypothesis; and (ii) the neurogenesis hypothesis. The neuroplasticity hypothesis explains how the hippocampal volume is decreased by the morphological changes of hippocampal neurons, such as the shortening length of dendrites and the decreased number and density of spines. The neurogenesis hypothesis explains how the hippocampal volume is decreased by the decrease of neurogenesis in the hippocampal dentate gyrus. These hypotheses are able to explain the latency of response to antidepressants. In this review, we first overview how the neuroplasticity and neurogenesis hypotheses have been developed. We then describe the details of these hypotheses.

Point-of-care companion diagnostic tests for personalizing psychiatric medications: fulfilling an unmet clinical need

Over the last decade stable isotope-labeled substrates have been used as probes for rapid, point-of-care, non-invasive and user-friendly phenotype breath tests to evaluate activity of drug metabolizing enzymes. These diagnostic breath tests can potentially be used as companion diagnostics by physicians to personalize medications, especially psychiatric drugs with narrow therapeutic windows, to monitor the progress of disease severity, medication efficacy and to study in vivo the pharmacokinetics of xenobiotics. Several genotype tests have been approved by the FDA over the last 15 years for both cytochrome P450 2D6 and 2C19 enzymes, however they have not been cleared for use in personalizing medications since they fall woefully short in identifying all non-responders to drugs, especially for the CYP450 enzymes. CYP2D6 and CYP2C19 are among the most extensively studied drug metabolizing enzymes, involved in the metabolism of approximately 30% of FDA-approved drugs in clinical use, associated with large individual differences in medication efficacy or tolerability essentially due to phenoconversion. The development and commercialization via FDA approval of the non-invasive, rapid (<60 min), in vivo, phenotype diagnostic breath tests to evaluate polymorphic CYP2D6 and CYP2C19 enzyme activity by measuring exhaled ¹³CO₂ as a biomarker in breath will effectively resolve the currently unmet clinical need for individualized psychiatric drug therapy. Clinicians could personalize treatment options for patients based on the CYP2D6 and CYP2C19 phenotype by selecting the optimal medication at the right initial and subsequent maintenance dose for the desired clinical outcome (i.e. greatest efficacy and minimal side effects).

Emotion Regulation Protects Against Recurrence of Depressive Symptoms Following Inpatient Care for Major Depressive Disorder

Relapse following response in psychotherapy for major depressive disorder (MDD) is a major concern. Emotion regulation (ER) has been discussed as a putative emerging and maintaining factor for depression. The purpose of the present study was to examine whether ER protects against recurrence of depression over and above residual symptoms of depression following inpatient care for MDD. ER skills (ERSQ-ES) and depression (HEALTH-49) were assessed in 193 patients with MDD (age, M = 47.4, SD = 9.6, 75.1% female, 100% Caucasian) at treatment discontinuation, 3 and 12 months after treatment. Multiple hierarchical regressions were used to examine general and specific ER as predictors of depressive symptoms at follow-ups. Higher general ER predicted lower depression over and beyond residual symptoms of depression at 3-month follow-up among treatment responders but not among treatment nonresponders. With regard to specific ER skills, readiness to confront and acceptance of undesired emotions predicted lower depressive symptoms beyond residual symptoms of depression 12 months, respectively 3 and 12 months after treatment. Findings of the present study indicate that targeting general ER might be more important for remitted and less important for nonremitted patients. Enhancing ER should hence be realized in a sequential treatment design, in which a continuation phase treatment with a specific focus on ER directly follows, once patients sufficiently responded to treatment. Acceptance of undesired emotion and readiness to confront situations that cue these emotions appear to be particularly important for protecting against recurrence of depression. Future research should clarify whether findings can be generalized to outpatient care.

Low-dose ketamine for treatment resistant depression in an academic clinical practice setting

BACKGROUND

Recent studies demonstrating a rapid, robust improvement in treatment resistant depression (TRD) following a single sub-anesthetic infusion of ketamine have generated much excitement. However, these studies are limited in their generalizability to the broader TRD population due to their subject exclusion criteria which typically limit psychiatric comorbidity, concurrent medication, and level of suicide risk. This paper describes the safety and efficacy of sub-anesthetic ketamine infusions in a naturalistic TRD patient sample participating in a real-world TRD treatment program within a major university health system.

METHODS

The effects of a sub-anesthetic dose (0.5mg/kg) of ketamine infused IV over forty minutes on TRD patients participating in a treatment program at the University of California, San Diego was investigated by retrospectively analyzing the medical charts of 41 adult TRD patients with a diagnosis of Major Depressive Disorder (MDD) or Bipolar Disorder (BD).

RESULTS

Subjects were aged 48.6, 78% white, 36.6% female, and 82.9% had MDD. Significant psychiatric comorbidity existed in 73%. Average pre-infusion BDI score was 32.6 ± 8.4 (S.D) and dropped to 16.8 ± 3.1 at 24-h post-infusion (p < 0.001). The 24-h response (≥ 50% reduction from pre-infusion) and remission (BDI <13) rates were 53.7% and 41.5%, respectively. Three quarters of responders maintained responder status at 7-days. Ketamine infusions were well tolerated with occasional nausea or anxiety and mild hemodynamic effects during the infusion.

LIMITATIONS

Retrospective nature of this study, lack of control group and use of self-report depression ratings scales.

CONCLUSIONS

This is the first published study of sub-anesthetic ketamine infusions in a real-world TRD population. The results suggest that this treatment is effective and well tolerated in this population.

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.

Ketamine treatment for depression: opportunities for clinical innovation and ethical foresight

We present a review and analysis of the ethical considerations in off-label ketamine use for severe, treatment-resistant depression. The analysis of ethical considerations is contextualised in an overview of the evidence for ketamine use in depression, and a review of the drug's safety profile. We find that, based on current evidence, ketamine use for severe, treatment-resistant depression does not violate ethical principles; however, clinicians and professional bodies must take steps to ensure that guidelines for good practice are enacted, that all experimental and trial data are made available through national registries, and that the risk potential of ketamine treatment continues to be monitored and modelled. We conclude with a set of key recommendations for oversight bodies that would support safe, effective, and ethical use of ketamine in depression.

Delineation of molecular pathway activities of the chronic antidepressant treatment response suggests important roles for glutamatergic and ubiquitin-proteasome systems

The aim of this study was to identify molecular pathways related to antidepressant response. We administered paroxetine to the DBA/2J mice for 28 days. Following the treatment, the mice were grouped into responders or non-responders depending on the time they spent immobile in the forced swim test. Hippocampal metabolomics and proteomics analyses revealed that chronic paroxetine treatment affects glutamate-related metabolite and protein levels differentially in the two groups. We found significant differences in the expression of N-methyl-d-aspartate receptor and neuronal nitric oxide synthase proteins between the two groups, without any significant alterations in the respective transcript levels. In addition, we found that chronic paroxetine treatment altered the levels of proteins associated with the ubiquitin-proteasome system (UPS). The soluble guanylate cyclase-β1, proteasome subunit α type-2 and ubiquitination levels were also affected in peripheral blood mononuclear cells from antidepressant responder and non-responder patients suffering from major depressive disorder. We submit that the glutamatergic system and UPS have a crucial role in the antidepressant treatment response in both mice and humans.

Susceptibility or resilience? Prenatal stress predisposes male rats to social subordination, but facilitates adaptation to subordinate status

Mood disorders such as major depressive disorder (MDD) affect a significant proportion of the population. Although progress has been made in the development of therapeutics, a large number of individuals do not attain full remission of symptoms and adverse side effects affect treatment compliance for some. In order to develop new therapies, there is a push for new models that better reflect the multiple risk factors that likely contribute to the development of depressive illness. We hypothesized that early life stress would exacerbate the depressive-like phenotype that we have previously observed in socially subordinate (SUB) adult male rats in the visible burrow system (VBS), a semi-natural, ethologically relevant environment in which males in a colony form a dominance hierarchy. Dams were exposed to chronic variable stress (CVS) during the last week of gestation, resulting in a robust and non-habituating glucocorticoid response that did not alter maternal food intake, body weight or litter size and weight. As adults, one prenatal CVS (PCVS) and one non-stressed (NS) male were housed in the VBS with adult females. Although there were no overt differences between PCVS and NS male offspring prior to VBS housing, a greater percentage of PCVS males became SUB. However, the depressive-like phenotype of SUB males was not exacerbated in PCVS males; rather, they appeared to better cope with SUB status than NS SUB males. They had lower basal plasma corticosterone than NS SUB males at the end of VBS housing. In situ hybridization for CRH in the PVN and CeA did not reveal any prenatal treatment or status effects, while NPY expression was higher within the MeA of dominant and subordinate males exposed to the VBS in comparison with controls, but with no effect of prenatal treatment. These data suggest that prenatal chronic variable stress may confer resilience to offspring when exposed to social stress in adulthood.

Modeling neurodevelopmental and psychiatric diseases with human iPSCs

Neurodevelopmental and psychiatric disorders, including autism spectrum disorder and schizophrenia, are complex and heterogeneous disorders that affect a large portion of the world's population. While the causes are still poorly understood, currently available treatments are limited; the development of rational therapeutics based on an understanding of the etiology and pathogenesis of the disease is imperative. The breakthrough technology of deriving induced pluripotent stem cells (iPSCs), reprogrammed from somatic cells of healthy subjects or patients, offers an unprecedented opportunity to recapitulate both normal and pathological development of human tissue, thereby opening up a new avenue for disease modeling and drug development in a more genetically tractable and disease-relevant system. Here, I review the recent progress in the use of human iPSCs for modeling neurodevelopmental and psychiatric disorders and developing novel therapeutic strategies, and discuss challenges in this rapidly moving field. © 2017 Wiley Periodicals, Inc.

Effects of ginseng on stress-related depression, anxiety, and the hypothalamic-pituitary-adrenal axis

Ginseng effectively regulates the immune response and the hormonal changes due to stress, thus maintaining homeostasis. In addition to suppressing the occurrence of psychological diseases such as anxiety and depression, ginseng also prevents stress-associated physiological diseases. Recent findings have revealed that ginseng is involved in adjusting the hypothalamic-pituitary-adrenal axis and controlling hormones, thus producing beneficial effects on the heart and brain, and in cases of bone diseases, as well as alleviating erectile dysfunction. Recent studies have highlighted the potential use of ginseng in the prevention and treatment of chronic inflammatory diseases such as diabetes, rheumatoid arthritis, and allergic asthma. However, the mechanism underlying the effects of ginseng on these stress-related diseases has not been completely established. In this review, we focus on the disease pathways caused by stress in order to determine how ginseng acts to improve health. Central to our discussion is how this effective and stable therapeutic agent alleviates the anxiety and depression caused by stress and ameliorates inflammatory diseases.