Pharmacologic approaches to treatment resistant depression: a re-examination for the modern era

Baseline levels of miR-223-3p correlate with the effectiveness of electroconvulsive therapy in patients with major depression

There is a strong medical need to develop suitable biomarkers to improve the diagnosis and treatment of depression, particularly in predicting response to certain therapeutic approaches such as electroconvulsive therapy (ECT). MicroRNAs are small non-coding RNAs that have the ability to influence the transcriptome as well as proteostasis at the systems level. Here, we investigate the role of circulating microRNAs in depression and response prediction towards ECT. Of the 64 patients with treatment-resistant major depression (MDD) who received ECT treatment, 62.5% showed a response, defined as a reduction of ≥50% in the MADRS total score from baseline. We performed smallRNA sequencing in blood samples that were taken before the first ECT, after the first and the last ECT. The microRNAome was compared between responders and non-responders. Co-expression network analysis identified three significant microRNA modules with reverse correlation between ECT- responders and non-responders, that were amongst other biological processes linked to inflammation. A candidate microRNA, namely miR-223-3p was down-regulated in ECT responders when compared to non-responders at baseline. In line with data suggesting a role of miR-223-3p in inflammatory processes we observed higher expression levels of proinflammatory factors Il-6, Il-1b, Nlrp3 and Tnf-α in ECT responders at baseline when compared to non-responders. ROC analysis of confirmed the diagnostic power of miR-223-3p demarcating ECT-responders from non-responder subjects (AUC = 0.76, p = 0.0031). Our data suggest that miR-223-3p expression and related cytokine levels could serve as predictors of response to ECT in individuals with treatment-resistant depressive disorders.

Dexmedetomidine in the Treatment of Depression: An Up-to-date Narrative Review

Depressive disorders (DD) are common, and their prevalence is expected to rise over the next decade. Depressive disorders are linked to significant morbidity and mortality. The clinical conundrum of depressive disorders lies in the heterogeneity of their phenomenology and etiology. Further, the currently available antidepressants have several limitations, including a delayed onset of action, limited efficacy, and an unfavorable side effect profile. In this review, Dexmedetomidine (DEX), a highly selective and potent α2-adrenergic receptor (α2-AR) agonist, is proposed as a potentially novel antidepressant with multiple mechanisms of action targeting various depression pathophysiological processes. These mechanisms include modulation of the noradrenergic system, regulation of neuroinflammation and oxidative stress, influence on the Brain-Derived Neurotrophic Factor (BDNF) levels, and modulation of neurotransmitter systems, such as glutamate. The review begins with an introduction before moving on to a discussion of DEX's pharmacological features. The pathophysiological and phenomenological targets of DD are also explored, along with the review of the existing preclinical and clinical evidence for DEX's putative anti-depressant effects. Finally, the review ends by presenting the pertinent conclusions and future directions.

Difficult decision-making in major depressive disorder: Practical guidance based on clinical research and experience

OBJECTIVES

To extend current published guidance regarding the management of major depression in clinical practice, by examining complex cases that reflect real-world patients, and to integrate evidence and experience into recommendations.

METHODS

The authors who contributed to recently published clinical practice guidelines were invited to identify important gaps in extant guidance. Drawing on clinical experience and shared knowledge, they then generated four fictional case studies to illustrate the real-world complexities of managing mood disorders. The cases focussed specifically on issues that are not usually addressed in clinical practice guidelines.

RESULTS

The four cases are discussed in detail and each case is summarised using a life chart and accompanying information. The four cases reflect important real-world challenges that clinicians face when managing mood disorders in day-to-day clinical practice. To partly standardise the presentation of each case and for ease of reference we provide a Time Line, History Box and Management Chart, along with a synopsis where relevant. Discussion and formulation of the cases illustrate how to manage the complexities of each case and provide one possible pathway to achieving functional recovery.

CONCLUSION

These cases draw on the combined clinical experience of the authors and illustrate how to approach diagnostic decision-making when treating major depressive disorder and having to contend with complex presentations. The cases are designed to stimulate discussion and provide a real-world context for the formulation of mood disorders.

Varied Composition and Underlying Mechanisms of Gut Microbiome in Neuroinflammation

The human gut microbiome has been implicated in a host of bodily functions and their regulation, including brain development and cognition. Neuroinflammation is a relatively newer piece of the puzzle and is implicated in the pathogenesis of many neurological disorders. The microbiome of the gut may alter the inflammatory signaling inside the brain through the secretion of short-chain fatty acids, controlling the availability of amino acid tryptophan and altering vagal activation. Studies in Korea and elsewhere highlight a strong link between microbiome dynamics and neurocognitive states, including personality. For these reasons, re-establishing microbial flora of the gut looks critical for keeping neuroinflammation from putting the whole system aflame through probiotics and allotransplantation of the fecal microbiome. However, the numerosity of the microbiome remains a challenge. For this purpose, it is suggested that wherever possible, a fecal microbial auto-transplant may prove more effective. This review summarizes the current knowledge about the role of the microbiome in neuroinflammation and the various mechanism involved in this process. As an example, we have also discussed the autism spectrum disorder and the implication of neuroinflammation and microbiome in its pathogenesis.

Intramuscular ketamine vs. escitalopram and aripiprazole in acute and maintenance treatment of patients with treatment-resistant depression: A randomized double-blind clinical trial

OBJECTIVE

Ketamine, an N-methyl D-aspartate (NMDA) receptor antagonist, can promote rapid action in the management of individuals with treatment-resistant depression (TRD) at sub-anesthetic doses. However, few studies have investigated the long-term use of ketamine administered intravenously (IV) and intranasally (IN). We report the design and rationale of a therapeutic trial for assessing the efficacy, safety, and tolerability of repeated-dose intramuscular (IM) ketamine vs. active treatment (escitalopram and aripiprazole) in TRD patients.

METHODS

A comparative, parallel-group, randomized double-blind trial assessing the efficacy, safety, and tolerability of acute (4 weeks) and maintenance (24 weeks) use of IM ketamine (0.75 mg/kg) vs. active control (escitalopram 15 mg and aripiprazole 5 mg) in individuals with moderate-severe intensity TRD (no psychotic symptoms) with or without suicide risk will be conducted. Patients with TRD (18-40 years) will be randomized and blinded to receive ketamine IM or active treatment at a 1:1 ratio for 4 weeks (active treatment) and 24 weeks (maintenance treatment). Subjects will be assessed using clinical scales, monitored for vital signs (VS) after application of injectable medication, and undergo neuropsychological tests. The primary outcome will be changed on the Montgomery-Åsberg Depression Rating Scale (MADRS) during the course of the trial. The study is in running.

RESULTS

This study can potentially yield evidence on the use of IM ketamine in the treatment of depressive disorders as an ultra-rapid low-cost therapy associated with less patient discomfort and reduced use of medical resources, and can elucidate long-term effects on different outcomes, such as neuropsychological aspects.

CONCLUSIONS

The trial can help promote the introduction of a novel accessible approach for the treatment of complex disease (TRD) and also allow refinement of its long-term use.

CLINICAL TRIAL REGISTRATION

https://clinicaltrials.gov/ct2/show/NCT04234776, identifier: NCT04234776.

Associations of Suicide Risk and Community Integration Among Patients With Treatment-Resistant Depression

INTRODUCTION

Treatment-resistant depression (TRD) is one of the primary causes of disability and a major risk for suicide among patients living in the community. However, the suicide risks and care needs for safety among patients with TRD during the community reintegration process appear to be underestimated. This study aimed to investigate the association between community integration and suicide risks among patients with treatment-resistant depression (TRD) with sub-analysis by gender.

METHODS

Patients diagnosed with major depressive disorder were recruited upon psychiatrists' referral in two general hospitals in northern Taiwan during 2018-2019. The participants who experienced more than two failed treatments of antidepressants with partial remission were defined as TRD. A structured questionnaire was used to collect socio-demographic, suicidality, and psychosocial information.

RESULTS

In a total of 125 participants, gender difference was identified in certain community integration aspects such as home integration, productivity, and electronic social networking. The male participants appeared to have better involvement in social contact with internet but slightly less video link than women, while women had higher level of home integration in the past month. The participants who performed worse in the social integration and better home-based activity or productivity levels had higher suicide risks including suicide ideation and overall suicide risks.

CONCLUSIONS

Community integration levels of home, social, and productivity were associated with suicidality in terms of overall suicide risk and recent suicide ideation. Facilitation of community integration at home and life arrangements might reduce suicide risks in TRD patients.

A Southeast Asia Consensus on the Definition and Management of Treatment-Resistant Depression

INTRODUCTION

Despite the abundance of literature on treatment-resistant depression (TRD), there is no universally accepted definition of TRD and available treatment pathways for the management of TRD vary across the Southeast Asia (SEA) region, highlighting the need for a uniform definition and treatment principles to optimize the management TRD in SEA.

METHODS

Following a thematic literature review and pre-meeting survey, a SEA expert panel comprising 13 psychiatrists with clinical experience in managing patients with TRD convened and utilized the RAND/UCLA Appropriateness Method to develop consensus-based recommendations on the appropriate definition of TRD and principles for its management.

RESULTS

The expert panel agreed that "pharmacotherapy-resistant depression" (PRD) is a more suitable term for TRD and defined it as "failure of two drug treatments of adequate doses, for 4-8 weeks duration with adequate adherence, during a major depressive episode". A stepwise treatment approach should be employed for the management of PRD - treatment strategies can include maximizing dose, switching to a different class, and augmenting or combining treatments. Non-pharmacological treatments, such as electroconvulsive therapy and repetitive transcranial magnetic stimulation, are also appropriate options for patients with PRD.

CONCLUSION

These consensus recommendations on the operational definition of PRD and treatment principles for its management can be adapted to local contexts in the SEA countries but should not replace clinical judgement. Individual circumstances and benefit-risk balance should be carefully considered while determining the most appropriate treatment option for patients with PRD.

Mortality Risk of Antipsychotic Augmentation for Adult Depression

(Reprinted with permission from PLOS ONE 2020).

A clinical approach to treatment resistance in depressed patients: What to do when the usual treatments don't work well enough?

BACKGROUND

Major depressive disorder is a common, recurrent, disabling and costly disorder that is often severe and/or chronic, and for which non-remission on guideline concordant first-line antidepressant treatment is the norm. A sizeable percentage of patients diagnosed with MDD do not achieve full remission after receiving antidepressant treatment. How to understand or approach these 'refractory', 'TRD' or 'difficult to treat' patients need to be revisited. Treatment resistant depression (TRD) has been described elsewhere as failure to respond to adequate treatment by two different antidepressants. This definition is problematic as it suggests that TRD is a subtype of major depressive disorder (MDD), inferring a boundary between TRD and depression that is not treatment resistant. However, there is scant evidence to suggest that a discrete TRD entity exists as a distinct subtype of MDD, which itself is not a discrete or homogeneous entity. Similarly, the boundary between TRD and other forms of depression is predicated at least in part on regulatory and research requirements rather than biological evidence or clinical utility.

AIM

This paper aims to investigate the notion of treatment failure in order to understand (i) what is TRD in the context of a broader formulation based on the understanding of depression, (ii) what factors make an individual patient difficult to treat, and (iii) what is the appropriate and individualised treatment strategy, predicated on an individual with refractory forms of depression?

METHOD

Expert contributors to this paper were sought internationally by contacting representatives of key professional societies in the treatment of MDD - World Federation of Societies for Biological Psychiatry, Australasian Society for Bipolar and Depressive Disorders, International Society for Affective Disorders, Collegium Internationale Neuro-Psychopharmacologium and the Canadian Network for Mood and Anxiety Treatments. The manuscript was prepared through iterative editing.

OUTCOMES

The concept of TRD as a discrete subtype of MDD, defined by failure to respond to pharmacotherapy, is not supported by evidence. Between 15 and 30% of depressive episodes fail to respond to adequate trials of 2 antidepressants, and 68% of individuals do not achieve remission from depression after a first-line course of antidepressant treatment. Failure to respond to antidepressant treatment, somatic therapies or psychotherapies may often reflect other factors including; biological resistance, diagnostic error, limitations of current therapies, psychosocial variables, a past history of exposure to childhood maltreatment or abuse, job satisfaction, personality disorders, co-morbid mental and physical disorders, substance use or non-adherence to treatment. Only a subset of patients not responding to antidepressant treatment can be explained through pharmacokinetic or pharmacodynamics mechanisms. We propose that non remitting MDD should be personalised, and propose a strategy of 'deconstructing depression'. By this approach, the clinician considers which factors contribute to making this individual both depressed and 'resistant' to previous therapeutic approaches. Clinical formulation is required to understand the nature of the depression. Many predictors of response are not biological, and reflect a confluence of biological, psychological, and sociocultural factors, which may influence the illness in a particular individual. After deconstructing depression at a personalised level, a personalised treatment plan can be constructed. The treatment plan needs to address the factors that have contributed to the individual's hard to treat depression. In addition, an individual with a history of illness may have a lot of accumulated life issues due to consequences of their illness, and these should be addressed in a recovery plan.

LIMITATIONS

A 'deconstructing depression' qualitative rubric does not easily provide clear inclusion and exclusion criteria for researchers wanting to investigate TRD.

CONCLUSIONS

MDD is a polymorphic disorder and many individuals who fail to respond to standard pharmacotherapy and are considered hard to treat. These patients are best served by personalised approaches that deconstruct the factors that have contributed to the patient's depression and implementing a treatment plan that adequately addresses these factors. The existence of TRD as a discrete and distinct subtype of MDD, defined by two treatment failures, is not supported by evidence.

Ketogenic diet for depression: A potential dietary regimen to maintain euthymia?

Approximately 30% of patients with major depressive disorder (MDD) present resistance to current pharmacological therapies. There is the possibility that an appropriate nutritional regimen can maintain euthymia. Poor dietary pattern and lack of nutritional knowledge are common among today's population; nutrient-rich foods are being replaced by highly processed foods that lead to a higher risk of developing chronic diseases such as metabolic syndrome, hypercholesterolemia, and diabetes. There is growing evidence of the beneficial role of vitamins and dietary supplements for improving symptoms in a range of affective disorders by regulating the gut microbiome, gut-brain axis, and neurotransmitter levels. Reduced GABA neurotransmission is regularly observed in MDD. Moreover, positive allosteric GABA modulators (i.e benzodiazepines) are widely prescribed to alleviate depression symptoms, but their use needs to be limited, as it can lead to addiction. An alternative option may be the adherence to a ketogenic diet, which consists of low-carbohydrate, moderate-protein, and high-fat intake. It is mainly known for its beneficial role in weight-loss, refractory epilepsy treatment, and balancing glucose levels. A ketogenic diet can also increase GABA levels to aid the mechanism of action of monoaminergic drugs. Thus, it could potentially be used in the treatment for affective disorders due to its potential role in GABA/glutamate balance. While more research is needed before this regimen can be regularly recommended to patients, here we discuss evidence that may encourage physicians to prescribe ketogenic diet as an adjuvant for patients receiving psychotherapy and pharmacology.

Practical recommendations for the management of treatment-resistant depression with esketamine nasal spray therapy: Basic science, evidence-based knowledge and expert guidance

OBJECTIVES

Despite the available therapies for treatment-resistant depression (TRD), there are a limited number that are evidence-based and effective in this hard-to-treat population. Esketamine nasal spray, an intranasal N-methyl-d-aspartate (NMDA) glutamate receptor antagonist, is a novel, fast-acting option in this patient population. This manuscript provides expert guidance on the practicalities of using esketamine nasal spray.

METHODS

A group of six European experts in major depressive disorder (MDD) and TRD, with clinical experience of treating patients with esketamine nasal spray, first generated practical recommendations, before editing and voting on these to develop consensus statements during an online meeting.

RESULTS

The final consensus statements encompass not only pre-treatment considerations for patients with TRD, but also specific guidelines for clinicians to consider during and post-administration of esketamine nasal spray.

CONCLUSIONS

Esketamine nasal spray is a novel, fast-acting agent that provides an additional treatment option for patients with TRD who have previously failed several therapies. The guidance here is based on the authors' experience and the available literature; however, further real-world use of esketamine nasal spray will add to existing knowledge. The recommendations offer practical guidance to clinicians who are unfamiliar with esketamine nasal spray.

Lithium and Therapeutic Targeting of GSK-3

Lithium salts have been in the therapeutic toolbox for better or worse since the 19th century, with purported benefit in gout, hangover, insomnia, and early suggestions that lithium improved psychiatric disorders. However, the remarkable effects of lithium reported by John Cade and subsequently by Mogens Schou revolutionized the treatment of bipolar disorder. The known molecular targets of lithium are surprisingly few and include the signaling kinase glycogen synthase kinase-3 (GSK-3), a group of structurally related phosphomonoesterases that includes inositol monophosphatases, and phosphoglucomutase. Here we present a brief history of the therapeutic uses of lithium and then focus on GSK-3 as a therapeutic target in diverse diseases, including bipolar disorder, cancer, and coronavirus infections.

Economic burden of treatment-resistant depression in privately insured US patients with co-occurring anxiety disorder and/or substance use disorder

OBJECTIVE

To assess the burden of treatment-resistant depression (TRD) among privately insured patients with anxiety disorder and/or substance use disorders (SUD).

METHODS

Adults <65 years old were identified in the Optum Health Care Solutions Inc. database (July 2009-March 2017). Among those with major depressive disorder (MDD) and antidepressant use, patients who initiated a third antidepressant (index date) after two regimens at adequate dose and duration were classified in the TRD cohort and patients without evidence of TRD were classified in the non-TRD MDD control cohort. The non-MDD control cohort comprised patients without MDD. In the non-TRD MDD and non-MDD cohorts, the index date was imputed to mimic the distribution of time in the TRD cohort from the first antidepressant to the index date or from the start of eligibility to the index date, respectively. Patients with <6 months of continuous insurance eligibility pre-/post-index, psychosis, schizophrenia, bipolar disorder and related conditions, dementia, and development disorders, and/or no baseline anxiety disorder and/or SUD were excluded. Patients with TRD were matched 1:1 to patients with non-TRD MDD and patients without MDD, based on exact matching factors (i.e. availability of work loss data) and propensity scores computed based on characteristics measured pre-index. Outcomes, including healthcare resource use (HRU) and costs, work productivity loss and related costs measured per patient per year ≤24 months post-index were compared between matched TRD, non-TRD MDD and non-MDD cohorts.

RESULTS

A total of 3166 patients were identified in the TRD cohort and matched to non-TRD MDD and non-MDD cohorts. Among patients with TRD (mean age 39 years, 60.5% female), 87.3% had an anxiety disorder, 24.1% had SUD. The TRD cohort had higher HRU vs non-TRD MDD and non-MDD cohorts: 0.32 vs 0.20 and 0.14 inpatient admissions, 0.91 vs 0.73 and 0.58 emergency department visits, and 23.8 vs 16.8 and 11.6 outpatient visits, respectively (all p < .01). The TRD cohort had higher healthcare costs ($16,674) vs non-TRD MDD ($10,945) and non-MDD ($6493) cohorts (all p < .01). Among patients with work loss data (N = 310/cohort), patients with TRD had more work loss days (54) and higher work loss-related costs ($13,674) vs patients with non-TRD MDD (32 days; $7131) and without MDD (17 days; $4798; all p < .01).

CONCLUSIONS

In patients with an anxiety disorder and/or SUD, TRD was associated with higher HRU, healthcare costs, work loss days and work loss-related costs.

Mortality risk of antipsychotic augmentation for adult depression

Importance

Randomized controlled trials have demonstrated increased all-cause mortality in elderly patients with dementia treated with newer antipsychotics. It is unknown whether this risk generalizes to non-elderly adults using newer antipsychotics as augmentation treatment for depression.

Objective

This study examined all-cause mortality risk of newer antipsychotic augmentation for adult depression.

Design

Population-based new-user/active comparator cohort study.

Setting

National healthcare claims data from the US Medicaid program from 2001–2010 linked to the National Death Index.

Participants

Non-elderly adults (25–64 years) diagnosed with depression who after ≥3 months of antidepressant monotherapy initiated either augmentation with a newer antipsychotic or with a second antidepressant. Patients with alternative indications for antipsychotic medications, such as schizophrenia, psychotic depression, or bipolar disorder, were excluded.

Exposure

Augmentation treatment for depression with a newer antipsychotic or with a second antidepressant.

Main outcome

All-cause mortality during study follow-up ascertained from the National Death Index.

Results

The analytic cohort included 39,582 patients (female = 78.5%, mean age = 44.5 years) who initiated augmentation with a newer antipsychotic (n = 22,410; 40% = quetiapine, 21% = risperidone, 17% = aripiprazole, 16% = olanzapine) or with a second antidepressant (n = 17,172). The median chlorpromazine equivalent starting dose for all newer antipsychotics was 68mg/d, increasing to 100 mg/d during follow-up. Altogether, 153 patients died during 13,328 person-years of follow-up (newer antipsychotic augmentation: n = 105, follow-up = 7,601 person-years, mortality rate = 138.1/10,000 person-years; antidepressant augmentation: n = 48, follow-up = 5,727 person-years, mortality rate = 83.8/10,000 person-years). An adjusted hazard ratio of 1.45 (95% confidence interval, 1.02 to 2.06) indicated increased all-cause mortality risk for newer antipsychotic augmentation compared to antidepressant augmentation (risk difference = 37.7 (95%CI, 1.7 to 88.8) per 10,000 person-years). Results were robust across several sensitivity analyses.

Conclusion

Augmentation with newer antipsychotics in non-elderly patients with depression was associated with increased mortality risk compared with adding a second antidepressant. Though these findings require replication and cannot prove causality, physicians managing adults with depression should be aware of this potential for increased mortality associated with newer antipsychotic augmentation.

Antidepressant efficacy and side effect burden: an updated guide for clinicians

Antidepressant treatment has been evolving and changing since the 1950s following the discovery of the classic antidepressant treatments including tricyclic antidepressants and monoamine oxidase inhibitors. The heterogeneity of the disorder became apparent in the beginning when individuals remained symptomatic despite medication compliance. This spurred further research in order to understand the neurobiology underlying the disorder. Subsequently, newer medications were designed to target specific neurotransmitters and areas of the brain involved in symptom development and maintenance. Our original review article looked at both classic and modern antidepressant medications used in the treatment of major depressive disorder. This manuscript is an update to the original review and serves to provide clinicians with information about novel antidepressant medications, augmentation strategies with atypical antipsychotics, over-the-counter medications, as well as nonpharmaceutical treatments that should be considered when treating each individual patient who remains symptomatic despite treatment efforts.

Epidemiology of pharmaceutically treated depression and treatment resistant depression in South Korea

Background

The epidemiology of pharmaceutically treated depression (PTD) and treatment resistant depression (TRD) is largely unknown in South Korea. The aim of this study was to develop a greater understanding of the characteristics of PTD and TRD in nearly the entire adult population in South Korea using the Health Insurance Review and Assessment Service (HIRA).

Method

Diagnostic codes and prescription data for South Korean adults were extracted from the HIRA. Subjects were included in the PTD cohort if they received at least one prescription for antidepressants and were diagnosed with depression. TRD was defined as PTD having two or more regimen failures of antidepressants or antipsychotics.

Results

In 2012, there were 41,256,396 adults in South Korea with 834,694 meeting the criteria for PTD (2.0%). Among subjects with PTD, 57% stopped treatment in less than 28 days of antidepressant supply. Tricyclic and tetracyclic antidepressants were the most frequently used antidepressants as a first-line regimen for PTD (44.3% of PTD) followed by selective serotonin reuptake inhibitors (32.1% of PTD). Results also indicated that 34,812 subjects developed TRD (4.2% of PTD). Median PTD and TRD durations were 28 and 623 days respectively. Proportions of psychiatric and non-psychiatric comorbidities were higher in TRD cases than in PTD cases that were not treatment resistant.

Conclusions

Despite a small proportion of patients with TRD, the prolonged duration of illness and higher comorbidity implies the need for better treatment.

TAK-137, an AMPA receptor potentiator with little agonistic effect, produces antidepressant-like effect without causing psychotomimetic effects in rats

Ketamine produces a rapid-onset antidepressant effect in patients with treatment-resistant depression (TRD), although it concurrently causes undesirable psychotomimetic side effects. Accumulating evidence suggests that ketamine produces antidepressant effects via activation of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPA-R), with consequent activation of the mammalian target of rapamycin (mTOR) pathway and up-regulation of brain-derived neurotrophic factor (BDNF). We previously reported that TAK-137, an AMPA-R potentiator with little agonistic effect, had potent procognitive effects with lower risks of bell-shaped dose-response and seizure induction. In this study, we characterized the potential of TAK-137 as a novel antidepressant in rats. In rat primary cortical neurons, TAK-137 increased the phosphorylated form of Akt, extracellular signal-regulated kinase, mTOR, and p70S6 kinase, and dose-dependently increased the expression level of BDNF protein. The antidepressant-like effects of ketamine and TAK-137 were assessed on the day after final administration using the novelty-suppressed feeding test in rats. A single intraperitoneal administration of ketamine shortened the latency to feed. Under these conditions, oral administration of TAK-137 for 3 days shortened the feeding latency. Ketamine induced hyperlocomotion and reduced prepulse inhibition, which may be associated with psychotomimetic effects, while TAK-137 did not. TAK-137 may be a safer and rapid-onset therapeutic drug for the treatment of major depressive disorder, including TRD.

The assessment of resistance to antidepressant treatment: Rationale for the Antidepressant Treatment History Form: Short Form (ATHF-SF)

There is considerable diversity in how treatment-resistant depression (TRD) is defined. However, every definition incorporates the concept that patients with TRD have not benefited sufficiently from one or more adequate trials of antidepressant treatment. This review examines the issues fundamental to the systematic evaluation of antidepressant treatment adequacy and resistance. These issues include the domains of interventions deemed effective in treatment of major depressive episodes (e.g., pharmacotherapy, brain stimulation, and psychotherapy), the subgroups of patients for whom distinct adequacy criteria are needed (e.g., bipolar vs. unipolar depression, psychotic vs. nonpsychotic depression), whether trials should be rated dichotomously as adequate or inadequate or on a potency continuum, whether combination and augmentation strategies require specific consideration, and the criteria used to evaluate the adequacy of treatment delivery (e.g., dose, duration), trial adherence, and clinical outcome. This review also presents the Antidepressant Treatment History Form: Short-Form (ATHF-SF), a completely revised version of an earlier instrument, and details how these fundamental issues were addressed in the ATHF-SF.

Number of illness episodes as predictor of residual symptoms in major depressive disorder

Notwithstanding major depressive disorder (MDD) is a recurring and chronic condition, relatively few variables have consistently been shown to predict its course. Residual depressive symptoms may be associated with disability and functional impairment but few studies evaluated clinical correlates associated with these symptoms and their impact on functioning after adjustment for potential confounders. Therefore, our study aimed to investigate factors associated with residual depressive symptoms and their impact on the course of MDD. The sample consisted of 210 consecutive MDD euthymic outpatients (67.6% females; mean age = 52.1 ± 15.5), admitted to the Section of Psychiatry, University of Genoa (Italy). Residuals depressive symptoms were significantly associated with female gender; use of short half-life benzodiazepines; longer duration of the current depressive episode; higher number of illness episodes; and higher duration of illness. Conversely, prior treatment with first-generation antipsychotics, later age of illness onset and first hospitalization were less frequently observed among patients with residual symptoms. After multivariate analyses, only duration of current illness episodes (ß = 0.003; p = <0.005) and substance abuse (ß = 0.042; p = <0.05) remained significantly associated with residual symptoms. Our findings indicate that residual depressive symptoms conferred a pernicious illness course in this specific cohort of MDD patients. Future trials mainly targeting these burdensome symptoms are warranted.

Absence of Claudin 11 in CNS Myelin Perturbs Behavior and Neurotransmitter Levels in Mice

Neuronal origins of behavioral disorders have been examined for decades to construct frameworks for understanding psychiatric diseases and developing useful therapeutic strategies with clinical application. Despite abundant anecdotal evidence for white matter etiologies, including altered tractography in neuroimaging and diminished oligodendrocyte-specific gene expression in autopsy studies, mechanistic data demonstrating that dysfunctional myelin sheaths can cause behavioral deficits and perturb neurotransmitter biochemistry have not been forthcoming. At least in part, this impasse stems from difficulties in identifying model systems free of degenerative pathology to enable unambiguous assessment of neuron biology and behavior in a background of myelin dysfunction. Herein we examine myelin mutant mice lacking expression of the Claudin11 gene in oligodendrocytes and characterize two behavioral endophenotypes: perturbed auditory processing and reduced anxiety/avoidance. Importantly, these behaviors are associated with increased transmission time along myelinated fibers as well as glutamate and GABA neurotransmitter imbalances in auditory brainstem and amygdala, in the absence of neurodegeneration. Thus, our findings broaden the etiology of neuropsychiatric disease to include dysfunctional myelin, and identify a preclinical model for the development of novel disease-modifying therapies.

Intranasal Cotinine Plus Krill Oil Facilitates Fear Extinction, Decreases Depressive-Like Behavior, and Increases Hippocampal Calcineurin A Levels in Mice

Failure in fear extinction is one of the more troublesome characteristics of posttraumatic stress disorder (PTSD). Cotinine facilitates fear memory extinction and reduces depressive-like behavior when administered 24 h after fear conditioning in mice. In this study, it was investigated the behavioral and molecular effects of cotinine, and other antidepressant preparations infused intranasally. Intranasal (IN) cotinine, IN krill oil, IN cotinine plus krill oil, and oral sertraline were evaluated on depressive-like behavior and fear retention and extinction after fear conditioning in C57BL/6 mice. Since calcineurin A has been involved in facilitating fear extinction in rodents, we also investigated changes of calcineurin in the hippocampus, a region key on contextual fear extinction. Short-term treatment with cotinine formulations was superior to krill oil and oral sertraline in reducing depressive-like behavior and fear consolidation and enhancing contextual fear memory extinction in mice. IN krill oil slowed the extinction of fear. IN cotinine preparations increased the levels of calcineurin A in the hippocampus of conditioned mice. In the light of the results, the future investigation of the use of IN cotinine preparations for the extinction of contextual fear memory and treatment of treatment-resistant depression (TRD) in PTSD is discussed.

Antipsychotic Prescriptions Among Adults With Major Depressive Disorder in Office-Based Outpatient Settings: National Trends From 2006 to 2015

OBJECTIVE

A recent moderately long-term study found an antipsychotic to be more effective than an antidepressant as the next-step treatment of unresponsive major depressive disorder (MDD). It is thus timely to examine recent trends in the pharmacoepidemiology of antipsychotic treatment of MDD.

METHODS

Data from the 2006-2015 National Ambulatory Medical Care Survey, nationally representative samples of office-based outpatient visits in adults with MDD (ICD-9-CM codes 296.20-296.26 and 296.30-296.36) (n = 4,044 unweighted), were used to estimate rates of antipsychotic prescribing over these 10 years. Multivariable logistic regression analysis identified demographic and clinical factors independently associated with antipsychotic use in MDD.

RESULTS

Antipsychotic prescribing for MDD increased from 18.5% in 2006-2007 to 24.9% in 2008-2009 and then declined to 18.9% in 2014-2015. Visits with adults 75 years or older showed the greatest decline from 27.0% in 2006-2007 to 10.7% in 2014-2015 (OR for overall trend = 0.73; 95% CI, 0.56-0.95). The most commonly prescribed antipsychotic agents were aripiprazole, olanzapine, quetiapine, and risperidone. Antipsychotic prescription was associated with being black or Hispanic, having Medicare among adults under 65 years or Medicaid as a primary source of payment, and receiving mental health counseling, 3 or more concomitant medications, and diagnosis of cannabis use disorder (P < .01).

CONCLUSIONS

Antipsychotics, prescribed for about one-fifth of adults with MDD, increased and then declined from 2006 to 2015, reflecting, first, FDA approval and then concern about adverse effects in the elderly. Future research should track evolving trends following the publication of evidence of greater long-term effectiveness of antipsychotic than antidepressant next-step therapy in adults with MDD.

Antipsychotic Medication Treatment Patterns in Adult Depression

OBJECTIVE

To characterize the role of antipsychotic medications in the community treatment of adult depression.

METHODS

We identified adults (aged 18-64 years) with new episodes of depression treatment (ICD-9-CM 296.2, 296.3, 300.4, or 311) in US national Medicaid data (2001-2010). Patients with alternative ICD-9-CM antipsychotic indications, such as schizophrenia or bipolar disorder, were excluded. Each patient was followed for at least 1 year to characterize antipsychotic and antidepressant treatment and emerging alternative antipsychotic indications. For patients without alternative indications through day 45 following start of antipsychotic treatment, antipsychotics were considered to be intended for treatment of depression. Among this group, we determined whether antipsychotic initiation was preceded by minimally adequate treatment with antidepressants, defined as active antidepressant treatment for ≥ 31 days prior to and including the day of antipsychotic initiation.

RESULTS

Within 1 year following onset, 14.0% of patients started an antipsychotic medication. A total of 41.3% of antipsychotic initiators developed an antipsychotic indication other than depression through day 45 following antipsychotic initiation, most often bipolar disorder or depression with psychotic features. The remaining 58.7% of antipsychotic initiators presumably started antipsychotics for nonpsychotic depression. Of these, 71.3% did not have minimally adequate antidepressant treatment prior to starting the antipsychotic medication.

CONCLUSION

Antipsychotic medications are used in approximately 1 in 7 patients with a new episode of depression. For 1 in 12 patients, the antipsychotic was considered to be intended for nonpsychotic depression. Almost three-quarters of these patients did not receive minimally adequate treatment with antidepressants prior to antipsychotic initiation. This pattern suggests potentially inappropriate and premature initiation of a drug class with substantial adverse effects and medical risks.

Antidepressants and suicidal behaviour in late life: a prospective population-based study of use patterns in new users aged 75 and above

Purpose

To investigate associations between antidepressant use patterns and risk of fatal and non-fatal suicidal behaviours in older adults who initiated antidepressant therapy.

Method

A national population-based cohort study conducted among Swedish residents aged ≥ 75 years who initiated antidepressant treatment. Patients who filled antidepressant prescriptions between January 1, 2007 and December 31, 2013 (N = 185,225) were followed until December 31, 2014. Sub-hazard ratios of suicides and suicide attempts associated with use patterns of antidepressants, adjusting for potential confounders such as serious depression were calculated using the Fine and Gray regression models.

Results

During follow-up, 295 suicides and 654 suicide attempts occurred. Adjusted sub-hazard ratios (aSHRs) were increased for both outcomes in those who switched to another antidepressant (aSHR for suicide 2.42, 95% confidence interval 1.65 to 3.55, and for attempt 1.76, 1.32 to 2.34). Elevated suicide risks were also observed in those who concomitantly filled anxiolytics (1.54, 1.20 to 1.96) and hypnotics (2.20, 1.69 to 2.85). Similar patterns were observed for the outcome suicide attempt. Decreased risk of attempt was observed among those with concomitant use of anti-dementia drugs (0.40, 0.27 to 0.59).

Conclusion

Switching antidepressants, as well as concomitant use of anxiolytics or hypnotics, may constitute markers of increased risk of suicidal behaviours in those who initiate antidepressant treatment in very late life. Future research should consider indication biases and the clinical characteristics of patients initiating antidepressant therapy.

Electronic supplementary material

The online version of this article (10.1007/s00228-017-2360-x) contains supplementary material, which is available to authorized users.

Exploring a post-traumatic stress disorder paradigm in Flinders sensitive line rats to model treatment-resistant depression II: response to antidepressant augmentation strategies

OBJECTIVE

Post-traumatic stress disorder (PTSD) displays high co-morbidity with major depression and treatment-resistant depression (TRD). Earlier work demonstrated exaggerated depressive-like symptoms in a gene×environment model of TRD and an abrogated response to imipramine. We extended the investigation by studying the behavioural and monoaminergic response to multiple antidepressants, viz. venlafaxine and ketamine with/without imipramine.

METHODS

Male Flinders sensitive line (FSL) rats, a genetic model of depression, were exposed to a time-dependent sensitisation (TDS) model of PTSD and compared with stress naive controls. 7 days after the TDS procedures, immobility and coping (swimming and climbing), behaviours in the forced swim test (FST) as well as hippocampal and cortical 5-hydroxyindoleacetic acid (5HIAA) and noradrenaline (NA) levels were analysed. Response to imipramine, venlafaxine and ketamine treatment (all 10 mg/kg×7 days) alone and in combination were subsequently studied.

RESULTS

TDS exacerbated depressive-like behaviour of FSL rats in the FST. Imipramine, venlafaxine and ketamine were ineffective as monotherapy in TDS-exposed FSL rats. However, combining imipramine with either venlafaxine or ketamine resulted in significant anti-immobility effects and enhanced coping behaviours. Only ketamine+imipramine (frontal-cortical 5HIAA and NA), ketamine alone (frontal-cortical and hippocampal NA) and venlafaxine+imipramine (frontal-cortical NA) altered monoamine responses versus untreated TDS-exposed FSL rats.

CONCLUSION

Exposure of FSL rats to TDS inhibits antidepressant response at behavioural and neurochemical levels. Congruent with TRD, imipramine plus venlafaxine or ketamine overcame treatment resistance in these animals. These data further support the hypothesis that exposure of FSL rats to a PTSD-like paradigm produces a valid animal model of TRD and warrants further investigation.

Efficacy of off-label augmentation in unipolar depression: A systematic review of the evidence

Treatment of unipolar depression with currently available antidepressants is still unsatisfactory. Augmentation with lithium or second generation antipsychotics is an established practice in non-responders to antidepressant monotherapy, but is also associated with a substantial non-response rate and with non-tolerance. Based on a systematic review of the literature, including meta-analyses, randomized controlled trials (RCTs), non-randomized comparative studies and case studies, off-label augmentation agents (administered in addition to an antidepressant, without FDA approval for treatment of MDD) were identified and evaluated regarding their efficacy using levels of evidence. The agents had to be added to an existing antidepressant regime with the aim of achieving an improved clinical response to an ongoing antidepressant treatment (augmentation) or an earlier onset of effect when starting antidepressant and augmentation agent simultaneously (acceleration). Five substances, modafinil, ketamine, pindolol, testosterone and estrogen (the latter two in hormone-deficient patients) were shown to be clinically effective in high evidence studies. For the six drugs dexamethasone, mecamylamine, riluzole, amantadine, pramipexole and yohimbine clear proof of efficacy was not possible due to low levels of evidence, small sample sizes or discordant results. For the two agents methylphenidate and memantine only studies with negative outcomes could be found. Overall, the quality of study designs was low and results were often contradictory. However, the use of pindolol, ketamine, modafinil, estrogen and testosterone might be an option for depressed patients who are not responding to antidepressant monotherapy or established augmentation strategies. Further high quality studies are necessary and warranted.

Augmentation of antidepressant effects of venlafaxine by agomelatine in mice are independent of kynurenine pathway

Agomelatine is a novel antidepressant with agonistic actions at melatonergic (MT1 and MT2 receptors) and antagonistic actions at 5HT-2C receptors. Venlafaxine, a serotonin norepinephrine reuptake inhibitor, is a widely prescribed drug in depression. The present study evaluated the low dose combinations of venlafaxine and agomelatine in chronic forced swim test (chronic FST) and tail suspension test (TST) in mice. Further, the effect of above drugs and their combination was evaluated on serum pro-inflammatory cytokines and hippocampal indole amine 2, 3 dioxygenase (IDO) activity by calculating the ratios of kynurenine/tryptophan (KYN/TRP) and serotonin/tryptophan (5HT/TRP). Treatment of agomelatine (4 mg/kg, i.p.) in combination with venlafaxine (4 mg/kg, i.p.) for 3 weeks showed a significant augmenting effect on both swimming and immobility time in chronic FST and immobility time in TST as compared to animals treated with either drug alone. While venlafaxine (4 mg/kg) reversed the elevated serum levels of IL-1β and IL-6 found in chronically stressed mice, agomelatine (4 and 8 mg/kg) failed to show such a reversal. Agomelatine alone and in combination also failed to reverse the increased activity of IDO as observed by enhanced KYN/TRP and reduced 5HT/TRP seen in chronically stressed mice indicating that the augmented antidepressant effect of venlafaxine by agomelatine is not mediated by pro-inflammatory cytokine-induced activation of IDO and further, kynurenine pathway.

Pharmacologic approaches to treatment resistant depression: Evidences and personal experience

AIM: To review evidence supporting pharmacological treatments for treatment-resistant depression (TRD) and to discuss them according to personal clinical experience.

METHODS: Original studies, clinical trials, systematic reviews, and meta-analyses addressing pharmacological treatment for TRD in adult patients published from 1990 to 2013 were identified by data base queries (PubMed, Google Scholar e Quertle Searches) using terms: “treatment resistant depression”, “treatment refractory depression”, “partial response depression”, “non responder depression”, “optimization strategy”, “switching strategy”, “combination strategy”, “augmentation strategy”, selective serotonin reuptake inhibitors antidepressants (SSRI), tricyclic antidepressants (TCA), serotonin norepinephrine reuptake inhibitors antidepressants, mirtazapine, mianserine, bupropione, monoamine oxidase inhibitor antidepressant (MAOI), lithium, thyroid hormones, second generation antipsychotics (SGA), dopamine agonists, lamotrigine, psychostimulants, dextromethorphan, dextrorphan, ketamine, omega-3 fatty acids, S-adenosil-L-metionine, methylfolat, pindolol, sex steroids, glucocorticoid agents. Other citations of interest were further identified from references reported in the accessed articles. Selected publications were grouped by treatment strategy: (1) switching from an ineffective antidepressant (AD) to a new AD from a similar or different class; (2) combining the current AD regimen with a second AD from a different class; and (3) augmenting the current AD regimen with a second agent not thought to be an antidepressant itself.

RESULTS: Switching from a TCA to another TCA provides only a modest advantage (response rate 9%-27%), while switching from a SSRI to another SSRI is more advantageous (response rate up to 75%). Evidence supports the usefulness of switching from SSRI to venlafaxine (5 positive trials out 6), TCA (2 positive trials out 3), and MAOI (2 positive trials out 2) but not from SSRI to bupropione, duloxetine and mirtazapine. Three reviews demonstrated that the benefits of intra- and cross-class switch do not significantly differ. Data on combination strategy are controversial regarding TCA-SSRI combination (positive results in old studies, negative in more recent study) and bupropion-SSRI combination (three open series studies but not three controlled trails support the useful of this combination) and positive regard mirtazapine (or its analogue mianserine) combination with ADs of different classes. As regards the augmentation strategy, available evidences supported the efficacy of TCA augmentation with lithium salts and thyroid hormone (T3), but are conflicting regard the SSRI augmentation with these two drugs (1 positive trial out of 4 for lithium and 3 out of 5 for thyroid hormone). Double-blind controlled studies showed the efficacy of AD augmentation with aripiprazole (5 positive trials out 5), quetiapine (3 positive trials out 3) and, at less extent, of fluoxetine augmentation with olanzapine (3 positive trials out 6), so these drugs received the FDA indication for the acute treatment of TRD. Results on AD augmentation with risperidone are conflicting (2 short term positive trials, 1 short-term and 1 long-term negative trials). Case series and open-label trials showed that AD augmentation with pramipexole or ropinirole, two dopamine agonists, could be an effective treatment for TRD (response rate to pramipexole 48%-74%, to ropinirole 40%-44%) although one recent double-blind placebo-controlled study does not support the superiority of pramipexole over placebo. Evidences do not justify the use of psychostimulants, omega-3 fatty acids, S-adenosil-L-metionine, methylfolate, pindolol, lamotrigine, and sex hormone as AD augmentation for TRD. Combining the available evidences with our experience we suggest treating non-responders to one SSRI bupropion or mirtazapine trial by switching to venlafaxine, and non-responders to one venlafaxine trial by switching to a TCA or, if TCA are not tolerated, combining mirtazapine with SSRI or venlafaxine. In non-responders to two or more ADs (including at least one TCA if tolerated) current AD regimen could be augmented with lithium salts (mainly in patients with bipolar depression or suicidality), SGAs (mostly aripiprazole) or DA-agonists (mostly pramipexole). In patients with severe TRD, i.e., non-responders to combination and augmentation strategies as well as to electroconvulsive therapy if workable, we suggest to try a combination plus augmentation strategy.

CONCLUSION: Our study identifies alternative effective treatment strategies for TRD. Further studies are needed to compare the efficacy of different strategies in more homogeneous subpopulations.

Combination of agomelatine and bupropion for treatment-resistant depression: results from a chart review study including a matched control group

INTRODUCTION

Although a growing selection of antidepressants is available, a significant number of patients do not reach clinical remission, despite multiple trials. Data concerning the efficacy and safety of combination therapies with newer antidepressants are limited.

METHODS

Fifteen inpatients with treatment-resistant depression (TRD), defined as Beck Depression Inventory-2 (BDI-2) scores >14 despite treatment with adequate doses of ≥ 1 antidepressant classes for ≥ 6 weeks, were treated with agomelatine plus bupropion for ≥6 weeks, and compared to 15 patients on antidepressant monotherapy with TRD matched on age, sex, and TRD stage based on retrospective chart review. The primary outcome was change in BDI-2 scores. Secondary outcomes included treatment response (BDI-2 score decrease by ≥ 50%), remission (BDI-2 score <13), routinely measured cardiometabolic parameters and adverse effects.

RESULTS

After a mean of 6 ± 1 weeks, BDI-2 scores decreased by 20.3 ± 5.6 points in the combination group compared to 12.5 ± 15.1 points in the monotherapy group (P = 0.073; Cohen's d = 0.7). Altogether, 73.3% in the combination group responded compared to 53.3% on monotherapy (P = 0.27). About 60.0% on combination therapy reached remission compared to 40% on monotherapy (P = 0.28), a difference equivalent to a number-needed-to-treat = 4. Treatment response was independent of the degree of TRD (P = 0.27). Bupropion-agomelatine cotreatment was well tolerated and laboratory adverse effect parameters were not altered.

CONCLUSION

Despite the small sample and uncontrolled study design, the good remission rate in TRD patients receiving agomelatine plus bupropion, particularly in comparison to the monotherapy group, indicates that this combination treatment should be explored further as a potentially promising strategy for patients with TRD.

The BDNF Val(66)Met polymorphism is associated with escitalopram response in depressed patients

BACKGROUND

The brain-derived neurotrophic factor (BDNF) gene is a candidate gene in therapeutic responses to antidepressants. The aim of the study was to determine the effects of BDNF allelic variability on responses to escitalopram treatment at 3 weeks after treatment initiation and at a 6-week endpoint.

METHODS

We included 187 Caucasian subjects with depression; 153 completed the 6-week study. Clinical evaluation was performed using the Montgomery and Asberg Depression Rating Scale (MADRS) before and after 3-6 weeks of treatment.

RESULTS

After 3 weeks of treatment, we saw significantly better treatment responses in the Met carriers and greater antidepressant resistance among the Val/Val homozygotes. Relative to Val/Val homozygous (59.78 %), a significantly greater proportion of subjects Met-carriers (77.94 %) responded to escitalopram treatment (χ (2) = 5.88, p = 0.015). After 6 weeks, we found the same pattern of results but this effect did not reach statistical significance (χ (2) = 2.07, p = 0.15).

CONCLUSION

These findings highlight a significant association between the BDNF valine to methionine substitution (Val(66)Met) polymorphism and the treatment response to escitalopram in a Caucasian population of severely depressed inpatients.

Pharmacological approaches to manage persistent symptoms of major depressive disorder: rationale and therapeutic strategies

Major depressive disorder (MDD) is a highly prevalent chronic psychiatric illness associated with significant morbidity, mortality, loss of productivity, and diminished quality of life. Typically, only a minority of patients responds to treatment and meet criteria for remission as residual symptoms may persist, the result of an inadequate course of treatment and/or the presence of persistent side effects. The foremost goal of treatment should be to restore patients to full functioning and eliminate or relieve all MDD symptoms, while being virtually free of troublesome side effects. The current available pharmacological options to manage persistent depressive symptoms include augmentation or adjunctive combination strategies, both of which target selected psychobiological systems and specific mood and somatic symptoms experienced by the patient. As well, non-pharmacological interventions including psychotherapies may be used in either first-line or adjunctive approaches. However, the evidence to date with respect to available adjunct therapies is limited by few studies and those published have utilized only a small number of subjects and lack enough data to allow for a consensus of expert opinion. This underlines the need for further longer term, large population-based studies and those that include comorbid populations, all of which are seen in real world community psychiatry.

National trends in second-generation antipsychotic augmentation for nonpsychotic depression

OBJECTIVE

This study estimates national trends and patterns in use of second-generation antipsychotics (SGAs) for adjunctive treatment of nonpsychotic adult depression in office-based practice.

METHOD

Twelve consecutive years (1999-2010) of the National Ambulatory Medical Care Survey were analyzed to estimate trends and patterns of adjunctive SGA treatment for adult (≥ 18 years) nonpsychotic depression in office-based visits. Adjunctive SGA use was examined among all office visits in which depression was diagnosed (N = 7,767), excluding visits with diagnoses for alternative SGA indications (schizophrenia, bipolar disorder, pervasive development disorder, psychotic depression, dementia) and those without an active antidepressant prescription.

RESULTS

From 1999 to 2010, 8.6% of adult depression visits included an SGA. SGA use rates increased from 4.6% in 1999-2000 to 12.5% in 2009-2010, with an adjusted odds ratio (AOR) for time trend of 2.78 (95% CI, 1.84-4.20). The increase in SGA augmentation was broad-based, with no significant differences in time trends between demographic and clinical subgroups. For the most recent survey years (2005-2010), SGA use rates were higher in visits to psychiatrists than to other physicians (AOR = 5.08; 95% CI, 2.96-8.73), visits covered by public than private insurance (AOR = 3.20; 95% CI, 2.25-4.54), visits with diagnosed major depressive disorder than other depressive disorders (AOR = 1.49; 95% CI, 1.08-2.06), and visits with diabetes, hyperlipidemia, or cardiovascular disease (AOR = 2.13; 95% CI, 1.12-4.03) and lower in visits by patients > 65 years than 18-44 years (AOR = 0.51; 95% CI, 0.32-0.82) and visits that included psychotherapy (AOR = 0.68; 95% CI, 0.47-0.96).

CONCLUSIONS

Between 1999 and 2010, SGAs were increasingly accepted in the outpatient treatment of adult nonpsychotic depression.

Interactions between diabetes and anxiety and depression: implications for treatment

Anxiety or depression may be a risk factor for the development of diabetes. This relationship may occur through a combination of genetic predispositions; epigenetic contingencies; exacerbating conditions such as metabolic syndrome (a precursor to diabetes); and other serious medical conditions. Medications used to treat anxiety and depression have significant side effects, such as weight gain, further increasing the possibility of developing diabetes. These components combine, interact, and reassemble to create a precarious system for persons with, or predisposed to, diabetes. Clinicians must be aware of these interrelationships to adequately treat the disease.

Characterization of treatment resistant depression episodes in a cohort of patients from a US commercial claims database

CONTEXT

Treatment Resistant Depression (TRD) is a significant and burdensome health concern.

OBJECTIVE

To characterize, compare and understand the difference between TRD and non-TRD patients and episodes in respect of their episode duration, treatment patterns and healthcare resource utilization.

DESIGN AND SETTING

Patients between 18 and 64 years with a new diagnosis of major depressive disorder (MDD) and without a previous or comorbid diagnosis of schizophrenia or bipolar disease were included from PharMetrics Integrated Database, a claims database of commercial insurers in the US. Episodes of these patients in which there were at least two distinct failed regimens involving antidepressants and antipsychotics were classified as TRD.

PATIENTS

82,742 MDD patients were included in the analysis; of these patients, 125,172 episodes were identified (47,654 of these were drug-treated episodes).

MAIN OUTCOME MEASURES

Comparison between TRD and non-TRD episodes in terms of their duration, number and duration of lines of treatment, comorbidities, and medical resource utilization.

RESULTS

Of the treated episodes, 6.6% (N = 3,134) met the criteria for TRD. The median time to an episode becoming TRD was approximately one year. The mean duration of a TRD episode was 1,004 days (vs. 452 days for a non-TRD episode). More than 75% of TRD episodes had at least four lines of therapy; half of the treatment regimens included a combination of drugs. Average hospitalization costs were higher for TRD than non-TRD episodes: $6,464 vs. $1,734, as were all other health care utilization costs.

CONCLUSIONS

While this study was limited to relatively young and commercially covered patients, used a rigorous definition of TRD and did not analyze for cause or consequence, the results highlight high unmet medical need and burden of TRD on patients and health care resources.

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

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

Psychotropic drug-drug interactions involving P-glycoprotein

Multidrug resistance P-glycoprotein (P-gp; also known as MDR1 and ABCB1) is expressed in the luminal membrane of the small intestine and blood-brain barrier, and the apical membranes of excretory cells such as hepatocytes and kidney proximal tubule epithelia. P-gp regulates the absorption and elimination of a wide range of compounds, such as digoxin, paclitaxel, HIV protease inhibitors and psychotropic drugs. Its substrate specificity is as broad as that of cytochrome P450 (CYP) 3A4, which encompasses up to 50 % of the currently marketed drugs. There has been considerable interest in variations in the ABCB1 gene as predictors of the pharmacokinetics and/or treatment outcomes of several drug classes, including antidepressants and antipsychotics. Moreover, P-gp-mediated transport activity is saturable, and is subject to modulation by inhibition and induction, which can affect the pharmacokinetics, efficacy or safety of P-gp substrates. In addition, many of the P-gp substrates overlap with CYP3A4 substrates, and several psychotropic drugs that are P-gp substrates are also CYP3A4 substrates. Therefore, psychotropic drugs that are P-gp substrates may cause a drug interaction when P-gp inhibitors and inducers are coadministered, or when psychotropic drugs or other medicines that are P-gp substrates are added to a prescription. Hence, it is clinically important to accumulate data about drug interactions through studies on P-gp, in addition to CYP3A4, to assist in the selection of appropriate psychotropic medications and in avoiding inappropriate combinations of therapeutic agents. There is currently insufficient information available on the psychotropic drug interactions related to P-gp, and therefore we summarize the recent clinical data in this review.

Meta-review of depressive subtyping models

BACKGROUND

Increasing dissatisfaction with the non-specificity of major depression has led many to propose more specific depressive subtyping models. The present meta-review seeks to map dominant depressive subtype models, and highlight definitions and overlaps.

METHODS

A database search in Medline and EMBASE of proposed depressive subtypes, and limited to reviews published between 2000 and 2011, was undertaken. Of the more than four thousand reviews, 754 were judged as potentially relevant and provided the base for the present selective meta-review.

RESULTS

Fifteen subtype models were identified. The subtypes could be divided into five molar categories of (1) symptom-based subtypes, such as melancholia, psychotic depression, atypical depression and anxious depression, (2) aetiologically-based subtypes, exemplified by adjustment disorders, early trauma depression, reproductive depression, perinatal depression, organic depression and drug-induced depression, (3) time of onset-based subtypes, as illustrated by early and late onset depression, as well as seasonal affective disorder, (4) gender-based (e.g. female) depression, and (5) treatment resistant depression. An overview considering definition, bio-psycho-social correlates and the evidence base of treatment options for each subtype is provided.

LIMITATIONS

Despite the large data base, this meta-review is nevertheless narrative focused.

CONCLUSIONS

Subtyping depression is a promising attempt to overcome the non-specificity of many diagnostic constructs such as major depression, both in relation to their intrinsic non-specificity and failure to provide treatment-specific information. If a subtyping model is to be advanced it would need, however, to demonstrate differential impacts of causes and treatments.

The hidden third: improving outcome in treatment-resistant depression

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

Interactions between antidepressants and P-glycoprotein at the blood-brain barrier: clinical significance of in vitro and in vivo findings

The drug efflux pump P-glycoprotein (P-gp) plays an important role in the function of the blood-brain barrier by selectively extruding certain endogenous and exogenous molecules, thus limiting the ability of its substrates to reach the brain. Emerging evidence suggests that P-gp may restrict the uptake of several antidepressants into the brain, thus contributing to the poor success rate of current antidepressant therapies. Despite some inconsistency in the literature, clinical investigations of potential associations between functional single nucleotide polymorphisms in ABCB1, the gene which encodes P-gp, and antidepressant response have highlighted a potential link between P-gp function and treatment-resistant depression (TRD). Therefore, co-administration of P-gp inhibitors with antidepressants to patients who are refractory to antidepressant therapy may represent a novel therapeutic approach in the management of TRD. Furthermore, certain antidepressants inhibit P-gp in vitro, and it has been hypothesized that inhibition of P-gp by such antidepressant drugs may play a role in their therapeutic action. The present review summarizes the available in vitro, in vivo and clinical data pertaining to interactions between antidepressant drugs and P-gp, and discusses the potential relevance of these interactions in the treatment of depression.

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

BACKGROUND

Patients with major depression respond to antidepressant treatment, but 10%-30% of them do not improve or show a partial response coupled with functional impairment, poor quality of life, suicide ideation and attempts, self-injurious behavior, and a high relapse rate. The aim of this paper is to review the therapeutic options for treating resistant major depressive disorder, as well as evaluating further therapeutic options.

METHODS

In addition to Google Scholar and Quertle searches, a PubMed search using key words was conducted, and relevant articles published in English peer-reviewed journals (1990-2011) were retrieved. Only those papers that directly addressed treatment options for treatment-resistant depression were retained for extensive review.

RESULTS

Treatment-resistant depression, a complex clinical problem caused by multiple risk factors, is targeted by integrated therapeutic strategies, which include optimization of medications, a combination of antidepressants, switching of antidepressants, and augmentation with non-antidepressants, psychosocial and cultural therapies, and somatic therapies including electroconvulsive therapy, repetitive transcranial magnetic stimulation, magnetic seizure therapy, deep brain stimulation, transcranial direct current stimulation, and vagus nerve stimulation. As a corollary, more than a third of patients with treatment-resistant depression tend to achieve remission and the rest continue to suffer from residual symptoms. The latter group of patients needs further study to identify the most effective therapeutic modalities. Newer biomarker-based antidepressants and other drugs, together with non-drug strategies, are on the horizon to address further the multiple complex issues of treatment-resistant depression.

CONCLUSION

Treatment-resistant depression continues to challenge mental health care providers, and further relevant research involving newer drugs is warranted to improve the quality of life of patients with the disorder.

Intravenous Ketamine for Treatment-Resistant Major Depressive Disorder

OBJECTIVE:

To evaluate the literature regarding the efficacy and safety of intravenous ketamine for treatment-resistant major depressive disorder (MDD).

DATA SOURCES:

A MEDLINE search (1966-September 2011) was performed using the terms treatment-resistant depression and ketamine. The search was restricted to articles published in English and reporting on use of ketamine in humans.

STUDY SELECTION AND DATA EXTRACTION:

All English-language articles identified from the data search were evaluated. Data were eligible for inclusion if they were primary literature and evaluated the efficacy of ketamine for depressive symptoms in treatment-resistant MDD. One case report, 3 case series, 3 open-label trials, and 1 randomized crossover trial were included.

DATA SYNTHESIS:

Several medications are available for treatment-resistant MDD; however, they are often limited by a slow onset of therapeutic effect and tolerability. It has been suggested that ketamine, a rapid-acting, N-methyl-D-aspartate glutamate receptor antagonist, may have antidepressant effects. Case reports, case series, and select trials evaluating ketamine use for depressive symptoms in treatment-resistant MDD have demonstrated a rapid effect for reductions of scores on a number of depression scales; however, its sustainability effect remains unknown. Several studies reported a large or moderate to large effect size for ketamine. Additionally, these studies showed that ketamine use in this patient population is associated with relatively well-tolerated adverse effects.

CONCLUSIONS:

Ketamine for treatment-resistant MDD requires further evaluation before it can be considered a viable treatment option.

Linking neurodevelopmental and synaptic theories of mental illness through DISC1

Recent advances in our understanding of the underlying genetic architecture of psychiatric disorders has blown away the diagnostic boundaries that are defined by currently used diagnostic manuals. The disrupted in schizophrenia 1 (DISC1) gene was originally discovered at the breakpoint of an inherited chromosomal translocation, which segregates with major mental illnesses. In addition, many biological studies have indicated a role for DISC1 in early neurodevelopment and synaptic regulation. Given that DISC1 is thought to drive a range of endophenotypes that underlie major mental conditions, elucidating the biology of DISC1 may enable the construction of new diagnostic categories for mental illnesses with a more meaningful biological foundation.

Toward affective circuit-based preclinical models of depression: sensitizing dorsal PAG arousal leads to sustained suppression of positive affect in rats

Little is known about why clinical depression feels so bad, perhaps because optimal neural circuit-based animal models of depression do not yet exist. Our goal here was to develop a strategy of inducing and measuring depressive-like states in the rat using neural circuits as both the independent and major dependent variables. We hypothesized that repeated electrical stimulation of the brain (ESB) within the dorsal periaqueductal gray (dPAG) aversion circuits would lead to a long-lasting suppression of 50kHz ultrasonic vocalizations (USVs), a validated measure of positive social affect. Fifteen consecutive daily 10min sessions of intermittent PAG-ESB reduced systematically evoked 50kHz USVs for up to 29 days following termination of ESB treatment, along with altering traditional measures of negative affect, including behavioral agitation, sucrose intake, and decreased exploratory behavior. These findings suggest a new affective circuit-based preclinical model of depression.

Nicotinic acetylcholine receptors and depression: a review of the preclinical and clinical literature

Many patients with depression fail to derive sufficient benefit from available treatment options, with up to a third never reaching remission despite multiple trials of appropriate treatment. Novel antidepressant agents are needed, and drugs targeting nicotinic acetylcholine receptors (nAChRs) appear to hold promise in this regard. nAChRs are involved in a variety of neurobiological systems implicated in the pathophysiology of depression. In addition to their role in cholinergic neurotransmission, they modulate dopamine function and influence inflammation and hypothalamic-pituitary-adrenal axis activity. Preclinical studies have suggested antidepressant-like effects of drugs targeting nAChRs, with the most consistent results observed with alpha4beta2 nAChR modulators such as varenicline and nonspecific nAChR antagonists such as mecamylamine. These agents appear to offer the most potential antidepressant-like efficacy when used in conjunction with other established antidepressant treatments. nAChR modulators also influence neural processes that appear to mediate the behavioral effects of antidepressants, such as hippocampal cell proliferation. Clinical evidence, while limited, shows preliminary efficacy for mecamylamine and varenicline. Taken together, the preclinical and clinical evidence suggests that drugs targeting nAChRs may represent an important new approach to the treatment of depression.

Separating hope from hype: some ethical implications of the development of deep brain stimulation in psychiatric research and treatment

Major depression is the most common serious brain disorder with a lifetime prevalence of up to 17%. Despite numerous options currently available for the treatment of depression, ~2 million people in the United States may experience an inadequate response to treatment (treatment-resistant depression [TRD]) at some point in their lives. The definition of TRD is variable, ranging from a failure to respond to two or more trials of antidepressant monotherapy to a failure to respond to four or more trials of different antidepressant therapies, including augmentation, combination therapy, and electroconvulsive therapy. It has been reported that as many as one-third of patients experience only a partial response to initial therapy, while nearly one-fifth are considered nonresponders. In addition to the obvious quality of life issues for the patient with TRD, the economic cost of TRD is significant. Annual healthcare costs increase significantly for patients with TRD with each successive change in antidepressant medication. Early in treatment (two medication changes), the annual costs are <$7,000/Year. By the eighth medication change, annual costs double to nearly $14,000/year.

There is a well-documented need for better long-term treatments for TRD, as witnessed by multiple efforts to establish treatment algorithms and best treatment steps when first and subsequent treatment measures prove inadequate. The Sequenced Treatment Alternatives to Relieve Depression (STAR*D) study, which analyzed outcome following several standardized antidepressive treatment steps, reported that 33% of patients did not respond even after four evidence-based treatment steps. A substantial proportion of patients are inadequately treated and some of these will go on to suffer from chronic, debilitating, and life-threatening symptoms.