The Impact of (the Concept of) Treatment-Resistant Depression: An Opinion Review

The complexity of treatment-resistant depression: A data-driven approach

BACKGROUND

Recent systematic reviews highlight great variability in defining and assessing treatment-resistant depression (TRD). A key problem is that definitions are consensus rather than data-led. This study seeks to offer a comprehensive socio-demographic and clinical description of a relevant sample.

METHODS

As part of a pragmatic randomized controlled trial, patients (N = 129) were managed in primary care for persistent depression and diagnosed with TRD. Data included previous treatment attempts, characteristics of the depressive illness, functioning, quality of life, co-occurring problems including suicidality, psychiatric and personality disorders, physical health conditions, and adverse events.

RESULTS

Findings show a severe and chronic course of depression with a duration of illness of 25+ years. Overall, 82.9 % had at least one other psychiatric diagnosis and 82.2 % at least one personality disorder; 69.8 % had significant musculoskeletal, gastrointestinal, genitourinary, or cardiovascular and respiratory physical health problems. All but 14 had severe difficulties in social and occupational functioning and reported severely impaired quality of life. Suicidal ideation was high: 44.9 % had made at least one serious suicide attempt and several reported multiple attempts with 17.8 % reporting a suicide attempt during childhood or adolescence. Of the patients, 79.8 % reported at least one adverse childhood experience.

LIMITATIONS

Potential for recall bias, not examining possible interactions, and absence of a control group.

CONCLUSIONS

Our findings reveal a complex and multifaceted condition and call for an urgent reconceptualization of TRD, which encompasses many interdependent variables and experiences. Individuals with TRD may be at a serious disadvantage in terms of receiving adequate treatment.

Thalamocortical functional connectivity and rapid antidepressant and antisuicidal effects of low-dose ketamine infusion among patients with treatment-resistant depression

Previous studies have shown an association between the thalamocortical dysconnectivity and treatment-resistant depression (TRD). Whether a single subanesthetic dose of ketamine may change thalamocortical connectivity among patients with TRD is unclear. Whether these changes in thalamocortical connectivity is associated with the antidepressant and antisuicidal effects of ketamine treatment is also unclear. Two resting-state functional MRIs were collected in two clinical trials of 48 patients with TRD (clinical trial 1; 32 receiving ketamine, 16 receiving a normal saline placebo) and 48 patients with TRD and strong suicidal ideation (clinical trial 2; 24 receiving ketamine, 24 receiving midazolam), respectively. All participants underwent rs-fMRI before and 3 days after infusion. Seed-based functional connectivity (FC) was analyzed in the left/right thalamus. FCs between the bilateral thalamus and right middle frontal cortex (BA46) and between the left thalamus and left anterior paracingulate gyrus (BA8) increased among patients in the ketamine group in clinical trials 1 and 2, respectively. FCs between the right thalamus and bilateral frontal pole (BA9) and between the right thalamus and left rostral paracingulate gyrus (BA10) decreased among patients in the ketamine group in clinical trials 1 and 2, respectively. However, the associations between those FC changes and clinical symptom changes did not survive statistical significance after multiple comparison corrections. Whether ketamine-related changes in thalamocortical connectivity may be associated with ketamine's antidepressant and antisuicidal effects would need further investigation. Clinical trials registration: UMIN Clinical Trials Registry (UMIN-CTR): Registration number: UMIN000016985 and UMIN000033916.

Risk Phenotypes, Comorbidities, Pharmacotherapy, and Electroconvulsive Therapy (ECT) in a Cohort with Difficult-to-Treat Depression in Comparison to an Unmedicated Control Group

BACKGROUND

Approximately 15-25% of depressed patients suffer from difficult-to-treat depression (DTD). Patients with DTD require a thorough examination to avoid the oversight of treatable (psychiatric/somatic) comorbidities or (pseudo-)resistance to antidepressant drugs (ADs). Polymorphisms of the cytochrome P450 (CYP) enzymes 2D6 and 2C19, which play a major role in the metabolism of ADs, may contribute to resistance to ADs. Patients with DTD might benefit from electroconvulsive therapy (ECT).

METHODS

We enrolled 109 patients with DTD and 29 untreated depressed controls (UDC). We assessed risk phenotypes, comorbidities, and treatment, including ECT. We also performed pharmacokinetic analyses of CYP2D6 and CYP2C19.

RESULTS

DTD patients significantly more often suffered from comorbid psychiatric diseases, especially ICD-10: F40-F48 (DTD:40.4%, UDC:17.2%, OR 11.87, p=0.011) than UDC patients. DTD patients receiving ECT were more likely to achieve remission (37.7% vs. 11.8%, OR=3.96, p=0.023). Treatment with ADs did not differ between remitters and non-remitters. No significant differences were observed in the distribution of CYP2D6 and CYP2C19 variants between both groups.

CONCLUSION

Patients with DTD appear to experience comorbid neurotic stress and somatoform disorders (ICD-10: F40 - F48) more frequently. Therefore, a comprehensive differential diagnosis is crucial when patients do not respond sufficiently to antidepressant medication. Genotyping CYP2D6 and CYP2C19 should be considered.

The impact of ATP-binding cassette transporters in the diseased brain: Context matters

ATP-binding cassette (ABC) transporters facilitate the movement of diverse molecules across cellular membranes, including those within the CNS. While most extensively studied in microvascular endothelial cells forming the blood-brain barrier (BBB), other CNS cell types also express these transporters. Importantly, disruptions in the CNS microenvironment during disease can alter transporter expression and function. Through this comprehensive review, we explore the modulation of ABC transporters in various brain pathologies and the context-dependent consequences of these changes. For instance, downregulation of ABCB1 may exacerbate amyloid beta plaque deposition in Alzheimer's disease and facilitate neurotoxic compound entry in Parkinson's disease. Upregulation may worsen neuroinflammation by aiding chemokine-mediated CD8 T cell influx into multiple sclerosis lesions. Overall, ABC transporters at the BBB hinder drug entry, presenting challenges for effective pharmacotherapy. Understanding the context-dependent changes in ABC transporter expression and function is crucial for elucidating the etiology and developing treatments for brain diseases.

Update on the assessment of resistance to antidepressant treatment: Rationale for the Antidepressant Treatment History Form: Short Form-2 (ATHF-SF2)

All definitions of treatment-resistant depression (TRD) require that patients have experienced insufficient benefit from one or more adequate antidepressant trials. Thus, identifying "failed, adequate trials" is key to the assessment of TRD. The Antidepressant Treatment History Form (ATHF) was one of the first and most widely used instruments that provided objective criteria in making these assessments. The original ATHF was updated in 2018 to the ATHF-SF, changing to a checklist format for scoring, and including specific pharmacotherapy, brain stimulation, and psychotherapy interventions as potentially adequate antidepressant treatments. The ATHF-SF2, presented here, is based on the consensus of the ATHF workgroup about the novel interventions introduced since the last revision and which should/should not be considered effective treatments for major depressive episodes. This document describes the rationale for these choices and, for each intervention, the minimal criteria for determining the adequacy of treatment administration. The Supplementary Material that accompanies this article provide the Scoring Checklist, Data Collection Forms (current episode and composite of previous episodes), and Instruction Manual for the ATHF-SF2.

Feasibility and Acceptability of a Mobile App-Based TEAM-CBT (Testing Empathy Assessment Methods-Cognitive Behavioral Therapy) Intervention (Feeling Good) for Depression: Secondary Data Analysis

BACKGROUND

The Feeling Good App is an automated stand-alone digital mobile mental health tool currently undergoing beta testing with the goal of providing evidence-informed self-help lessons and exercises to help individuals reduce depressive symptoms without guidance from a mental health provider. Users work through intensive basic training (IBT) and ongoing training models that provide education regarding cognitive behavioral therapy principles from a smartphone.

OBJECTIVE

The key objective of this study was to perform a nonsponsored third-party academic assessment of an industry-generated data set; this data set focused on the safety, feasibility, and accessibility of a commercial automated digital mobile mental health app that was developed to reduce feelings associated with depression.

METHODS

The Feeling Good App development team created a waitlist cohort crossover design and measured symptoms of depression and anxiety using the Patient Health Questionnaire-9, Generalized Anxiety Disorder-7, and an app-specific measure of negative feelings called the 7 Dimension Emotion Slider (7-DES). The waitlist cohort crossover design divided the participants into 2 groups, where 48.6% (141/290) of the participants were given immediate access to the apps, while 51.4% (149/290) were placed on a 2-week waitlist before being given access to the app. Data collected by the Feeling Good App development team were deidentified and provided to the authors of this paper for analysis through a nonsponsored university data use agreement. All quantitative data were analyzed using SPSS Statistics (version 28.0; IBM Corp). Descriptive statistics were calculated for demographic variables. Feasibility and acceptability were descriptively assessed. All participants included in the quantitative data were given access to the Feeling Good App; this study did not include a control group.

RESULTS

In terms of safety, there was no statistically significant change in suicidality from preintervention to postintervention time points (t288=0.0; P>.99), and there was a statistically significant decrease in hopelessness from preintervention to postintervention time points (F289=30.16; P<.01). In terms of acceptability, 72.2% (166/230) of the users who started the initial 2-day IBT went on to complete it, while 34.8% (80/230) of the users who started IBT completed the entirety of the apps' 4-week protocol (150/230, 65.22% dropout rate over 4 weeks).

CONCLUSIONS

This study is the first reported proof-of-concept evaluation of the Feeling Good App in terms of safety, feasibility, and statistical trends within the data set. It demonstrates a feasible and novel approach to industry and academic collaboration in the process of developing a digital mental health technology translated from an existing evidence-informed treatment. The results support the prototype app as safe for a select nonclinical population. The app had acceptable levels of engagement and dropouts throughout the intervention. Those who stay engaged showed reductions in symptom severity of depression warranting further investigation of the app's efficacy.

miRNAs in treatment-resistant depression: a systematic review

BACKGROUND

Treatment-resistant depression (TRD) is a condition in a subset of depressed patients characterized by resistance to antidepressant medications. The global prevalence of TRD has been steadily increasing, yet significant advancements in its diagnosis and treatment remain elusive despite extensive research efforts. The precise underlying pathogenic mechanisms are still not fully understood. Epigenetic mechanisms play a vital role in a wide range of diseases. In recent years, investigators have increasingly focused on the regulatory roles of miRNAs in the onset and progression of TRD. miRNAs are a class of noncoding RNA molecules that regulate the translation and degradation of their target mRNAs via interaction, making the exploration of their functions in TRD essential for elucidating their pathogenic mechanisms.

METHODS AND RESULTS

A systematic search was conducted in four databases, namely PubMed, Web of Science, Cochrane Library, and Embase, focusing on studies related to treatment-resistant depression and miRNAs. The search was performed using terms individually or in combination, such as "treatment-resistant depression," "medication-resistant depression," and "miRNAs." The selected articles were reviewed and collated, covering the time period from the inception of each database to the end of February 2024. We found that miRNAs play a crucial role in the pathophysiology of TRD through three main aspects: 1) involvement in miRNA-mediated inflammatory responses (including miR-155, miR-345-5p, miR-146a, and miR-146a-5p); 2) influence on 5-HT transport processes (including miR-674,miR-708, and miR-133a); and 3) regulation of synaptic plasticity (including has-miR-335-5p,has-miR- 1292-3p, let-7b, and let-7c). Investigating the differential expression and interactions of these miRNAs could contribute to a deeper understanding of the molecular mechanisms underlying TRD.

CONCLUSIONS

miRNAs might play a pivotal role in the pathogenesis of TRD. Gaining a deeper understanding of the roles and interrelations of miRNAs in TRD will contribute to elucidating disease pathogenesis and potentially provide avenues for the development of novel diagnostic and therapeutic strategies.

Schema therapy versus treatment as usual for outpatients with difficult-to-treat depression: study protocol for a parallel group randomized clinical trial (DEPRE-ST)

BACKGROUND

About one third of patients with depression are in a condition that can be termed as "difficult-to-treat". Some evidence suggests that difficult-to-treat depression is associated with a higher frequency of childhood trauma and comorbid personality disorders or accentuated features. However, the condition is understudied, and the effects of psychotherapy for difficult-to-treat depression are currently uncertain. The aim of this trial is to investigate the beneficial and harmful effects of 30 sessions of individual schema therapy versus treatment as usual for difficult-to-treat depression in the Danish secondary, public mental health sector.

METHODS

In this randomized, multi-centre, parallel-group, superiority clinical trial, 129 outpatients with difficult-to-treat depression will be randomized (1:1) to 30 sessions of individual schema therapy or treatment as usual; in this context mainly group-based, short-term cognitive behaviour or psychodynamic therapy. The primary outcome is the change from baseline in depressive symptoms 12 months after randomization, measured on the observer-rated 6-item Hamilton Rating Scale for Depression. The secondary outcomes are health-related quality of life assessed with the European Quality of Life 5 Dimensions 5 Level Version, functional impairment assessed with the Work and Social Adjustment Scale, psychological wellbeing assessed with the WHO-5 Well-being Index, and negative effects of treatment assessed with the Negative Effects Questionnaire. Exploratory outcomes are improvement on patient self-defined outcomes, personal recovery, anxiety symptoms, anger reactions, metacognitive beliefs about anger, and perseverative negative thinking. Outcomes will be assessed at 6, 12, and 24 months after randomization; the 12-month time-point being the primary time-point of interest. Outcome assessors performing the depression-rating, data managers, statisticians, the data safety and monitoring committee, and conclusion makers for the outcome article will be blinded to treatment allocation and results. To assess cost-effectiveness of the intervention, a health economic analysis will be performed.

DISCUSSION

This trial will provide evidence on the beneficial and harmful effects, as well as the cost-effectiveness of schema therapy versus treatment as usual for outpatients with difficult-to-treat depression. The results can potentially improve treatment for a large and understudied patient group.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05833087. Registered on 15th April 2023 (approved without prompts for revision on 27th April 2023).

Multiomics and blood-based biomarkers of electroconvulsive therapy in severe and treatment-resistant depression: study protocol of the DetECT study

Electroconvulsive therapy (ECT) is commonly used to treat treatment-resistant depression (TRD). However, our knowledge of the ECT-induced molecular mechanisms causing clinical improvement is limited. To address this issue, we developed the single-center, prospective observational DetECT study ("Multimodal Biomarkers of ECT in TRD"; registered 18/07/2022, www.clinicalTrials.gov , NCT05463562). Its objective is to identify molecular, psychological, socioeconomic, and clinical biomarkers of ECT response in TRD. We aim to recruit n = 134 patients in 3 years. Over the course of 12 biweekly ECT sessions (± 7 weeks), participant blood is collected before and 1 h after the first and seventh ECT and within 1 week after the twelfth session. In pilot subjects (first n = 10), additional blood draws are performed 3 and 6 h after the first ECT session to determine the optimal post-ECT blood draw interval. In blood samples, multiomic analyses are performed focusing on genotyping, epigenetics, RNA sequencing, neuron-derived exosomes, purines, and immunometabolics. To determine clinical response and side effects, participants are asked weekly to complete four standardized self-rating questionnaires on depressive and somatic symptoms. Additionally, clinician ratings are obtained three times (weeks 1, 4, and 7) within structured clinical interviews. Medical and sociodemographic data are extracted from patient records. The multimodal data collected are used to perform the conventional statistics as well as mixed linear modeling to identify clusters that link biobehavioural measures to ECT response. The DetECT study can provide important insight into the complex mechanisms of ECT in TRD and a step toward biologically informed and data-driven-based ECT biomarkers.

Implementation strategies to build mental health-care capacity in Malawi: a health-economic evaluation

BACKGROUND

Depression is a major contributor to morbidity and mortality in sub-Saharan Africa. Due to low system capacity, three in four patients with depression in sub-Saharan Africa go untreated. Despite this, little attention has been paid to the cost-effectiveness of implementation strategies to scale up evidence-based depression treatment in the region. In this study, we investigate the cost-effectiveness of two different implementation strategies to integrate the Friendship Bench approach and measurement-based care in non-communicable disease clinics in Malawi.

METHODS

The two implementation strategies tested in this study are part of a trial, in which ten clinics were randomly assigned (1:1) to a basic implementation package consisting of an internal coordinator acting as a champion (IC-only group) or to an enhanced package that complemented the basic package with quarterly external supervision, and audit and feedback of intervention delivery (IC + ES group). We included material costs, training costs, costs related to project-wide meetings, transportation and medication costs, time costs related to internal champion activities and depression screening or treatment, and costs of external supervision visits if applicable. Outcomes included the number of patients screened with the patient health questionnaire 2 (PHQ-2), cases of remitted depression at 3 and 12 months, and disability-adjusted life-years (DALYs) averted. We compared the cost-effectiveness of both packages to the status quo (ie, no intervention) using a micro-costing-informed decision-tree model.

FINDINGS

Relative to the status quo, IC + ES would be on average US$10 387 ($1349-$17 365) more expensive than IC-only but more effective in achieving remission and averting DALYs. The cost per additional remission would also be lower with IC + ES than IC-only at 3 months ($119 vs $223) and 12 months ($210 for IC + ES; IC-only dominated by the status quo at 12 months). Neither package would be cost-effective under the willingness-to-pay threshold of $65 per DALY averted currently used by the Malawian Ministry of Health. However, the IC + ES package would be cost-effective in relation to the commonly used threshold of three times per-capita gross domestic product per DALY averted.

INTERPRETATION

Investing in supporting champions might be an appropriate use of resources. Although not currently cost-effective by Malawian willingness-to-pay standards compared with the status quo, the IC + ES package would probably be a cost-effective way to build mental health-care capacity in resource-constrained settings in which decision makers use higher willingness-to-pay thresholds.

FUNDING

National Institute of Mental Health.

Stanford neuromodulation therapy for treatment-resistant depression: a systematic review

Objective

This systematic review of randomized controlled studies (RCTs) and observational studies evaluated the efficacy and safety of stanford neuromodulation therapy (SNT) for patients with treatment-resistant depression (TRD).

Methods

A systematic search (up to 25 September, 2023) of RCTs and single-arm prospective studies was conducted.

Results

One RCT (n = 29) and three single-arm prospective studies (n = 34) met the study entry criteria. In the RCT, compared to sham, active SNT was significantly associated with higher rates of antidepressant response (71.4% versus 13.3%) and remission (57.1% versus 0%). Two out of the three single-arm prospective studies reported the percentage of antidepressant response after completing SNT, ranging from 83.3% (5/6) to 90.5% (19/21). In the three single-arm prospective studies, the antidepressant remission rates ranged from 66.7% (4/6) to 90.5% (19/21). No severe adverse events occurred in all the four studies.

Conclusion

This systematic review found SNT significantly improved depressive symptoms in patients with TRD within 5 days, without severe adverse events.

Treatment-Resistant Depression in America Latina study: one-year follow-up of treatment resistant depression patients under standard of care reveals insights on quality of life, disability, work impairment, and depressive symptoms

Introduction

Depressive Disorders are on the rise worldwide. This is also the case in Latin America (LatAm). Treatment-Resistant Depressive Disorder (TRD) poses additional burden to patients with depression. Impacts quality of life (QoL) and other dimensions, and standard of care (SOC) is insufficient to achieve the desired clinical outcomes. Evidence from LatAm is, however, lacking. The present study was devised as a 1-year follow-up of the SOC in TRD patients in LatAm to explore the burden of TRD.

Methods

This was an observational, multinational, longitudinal study. Patients with clinical diagnosis of TRD in LatAm were included in a 1-year follow-up with SOC. Beyond the Sociodemographic characterization, outcome measures were QoL (EQ-5D-5L), disability (Sheehan Disability Scale - SDS), work productivity (Work Productivity and Activity Incapacity Questionnaire: depression - WPAI:D) and depression severity (Patient Health Questionnaire-PHQ9). Patients were assessed every 3-months and comparison was performed based on change from baseline to each visit and end of study (EOS - 12 months).

Results

Patients averaged 48 (± 13.12) years, mostly female (80.9%) and married/consensual union (42.5%) or single patients (34.4%). Despite the SOC treatment, three-quarters of the patients remained symptomatic at EOS, regardless of the significant longitudinal decrease (p ≤ 0.001). Similar trends were found for disability (p ≤ 0.001) -82.2% of the patients reporting work/school disruption at EOS-, percentage of work (34%) and activity impairment (40%) at EOS (p ≤ 0.001) and only 29.2% of patients with depressive severity "none" at EOS (p ≤ 0.001). The results portray the need to improve clinical outcomes in this complex and burdensome disease in LatAm.

Discussion

Here we show that the burden of TRD remains significant in essential dimensions of everyday life at EOS underlining the need for better therapeutic solutions. The improvements in most patients do not provide the desired outcome of return to the state before the condition. Further research should focus on identifying which treatments provide better outcomes in a real-world context.

Treatment-resistant depression: definition, prevalence, detection, management, and investigational interventions

Treatment-resistant depression (TRD) is common and associated with multiple serious public health implications. A consensus definition of TRD with demonstrated predictive utility in terms of clinical decision-making and health outcomes does not currently exist. Instead, a plethora of definitions have been proposed, which vary significantly in their conceptual framework. The absence of a consensus definition hampers precise estimates of the prevalence of TRD, and also belies efforts to identify risk factors, prevention opportunities, and effective interventions. In addition, it results in heterogeneity in clinical practice decision-making, adversely affecting quality of care. The US Food and Drug Administration (FDA) and the European Medicines Agency (EMA) have adopted the most used definition of TRD (i.e., inadequate response to a minimum of two antidepressants despite adequacy of the treatment trial and adherence to treatment). It is currently estimated that at least 30% of persons with depression meet this definition. A significant percentage of persons with TRD are actually pseudo-resistant (e.g., due to inadequacy of treatment trials or non-adherence to treatment). Although multiple sociodemographic, clinical, treatment and contextual factors are known to negatively moderate response in persons with depression, very few factors are regarded as predictive of non-response across multiple modalities of treatment. Intravenous ketamine and intranasal esketamine (co-administered with an antidepressant) are established as efficacious in the management of TRD. Some second-generation antipsychotics (e.g., aripiprazole, brexpiprazole, cariprazine, quetiapine XR) are proven effective as adjunctive treatments to antidepressants in partial responders, but only the olanzapine-fluoxetine combination has been studied in FDA-defined TRD. Repetitive transcranial magnetic stimulation (TMS) is established as effective and FDA-approved for individuals with TRD, with accelerated theta-burst TMS also recently showing efficacy. Electroconvulsive therapy is regarded as an effective acute and maintenance intervention in TRD, with preliminary evidence suggesting non-inferiority to acute intravenous ketamine. Evidence for extending antidepressant trial, medication switching and combining antidepressants is mixed. Manual-based psychotherapies are not established as efficacious on their own in TRD, but offer significant symptomatic relief when added to conventional antidepressants. Digital therapeutics are under study and represent a potential future clinical vista in this population.

Association of Neurofilament Light Chain With the Antidepressant Effects of Low-Dose Ketamine Infusion Among Patients With Treatment-Resistant Depression

BACKGROUND

The role of neurofilament light chain (NFL) in treatment-resistant depression (TRD) is unclear. Whether baseline NFL concentrations are associated with the antidepressant effects of low-dose ketamine infusion has not been determined.

METHODS

The NFL concentrations of 71 patients with TRD and 17 healthy controls were assessed. Patients with TRD were randomly administered a single infusion of 0.5 mg/kg ketamine, 0.2 mg/kg ketamine, or normal saline. Depressive symptoms were assessed before infusion and sequentially at postinfusion timepoints (after 240 minutes and after 2-7 and 14 days) using the Hamilton Depression Rating Scale (HDRS).

RESULTS

After adjustment for age, sex, and body mass index, patients with TRD were more likely to have higher concentrations of NFL than healthy controls (P < .001). A generalized estimating equation model with adjustments for infusion group, age, sex, body mass index, and baseline HDRS scores showed that baseline NFL concentrations were positively associated with subsequent HDRS scores following low-dose ketamine infusion (P = .038).

DISCUSSION

Higher concentrations of NFL were observed among patients with TRD compared with healthy controls. Baseline NFL concentrations may predict the antidepressant effects of low-dose ketamine infusion.

The Montreal model: an integrative biomedical-psychedelic approach to ketamine for severe treatment-resistant depression

Background

Subanesthetic ketamine has accumulated meta-analytic evidence for rapid antidepressant effects in treatment-resistant depression (TRD), resulting in both excitement and debate. Many unanswered questions surround ketamine's mechanisms of action and its integration into real-world psychiatric care, resulting in diverse utilizations that variously resemble electroconvulsive therapy, conventional antidepressants, or serotonergic psychedelics. There is thus an unmet need for clinical approaches to ketamine that are tailored to its unique therapeutic properties.

Methods

This article presents the Montreal model, a comprehensive biopsychosocial approach to ketamine for severe TRD refined over 6 years in public healthcare settings. To contextualize its development, we review the evidence for ketamine as a biomedical and as a psychedelic treatment of depression, emphasizing each perspectives' strengths, weaknesses, and distinct methods of utilization. We then describe the key clinical experiences and research findings that shaped the model's various components, which are presented in detail.

Results

The Montreal model, as implemented in a recent randomized clinical trial, aims to synergistically pair ketamine infusions with conventional and psychedelic biopsychosocial care. Ketamine is broadly conceptualized as a brief intervention that can produce windows of opportunity for enhanced psychiatric care, as well as powerful occasions for psychological growth. The model combines structured psychiatric care and concomitant psychotherapy with six ketamine infusions, administered with psychedelic-inspired nonpharmacological adjuncts including rolling preparative and integrative psychological support.

Discussion

Our integrative model aims to bridge the biomedical-psychedelic divide to offer a feasible, flexible, and standardized approach to ketamine for TRD. Our learnings from developing and implementing this psychedelic-inspired model for severe, real-world patients in two academic hospitals may offer valuable insights for the ongoing roll-out of a range of psychedelic therapies. Further research is needed to assess the Montreal model's effectiveness and hypothesized psychological mechanisms.

Viewpoint: Difficult-to-treat depression versus treatment-resistant depression: A new integrative perspective for managing depression

In the STAR*D study, the efficacy of treatments for major depression was examined. It was found that, while many responded to the initial antidepressant treatment, only 30% of participants achieved complete remission. Concerning treatment resistance in depression, there is a recent distinction emerging between treatment-resistant depression (TRD) and difficult-to-treat depression (DTD). Historically, TRD and DTD have been conflated, but it is essential to recognize them as separate entities. While TRD is characterized by a patient's inadequate response to two or more consecutive antidepressant treatments given for an adequate duration and dosage without achieving acceptable therapeutic effects, DTD describes a clinical category where patients do not achieve full symptom control despite various therapeutic approaches. The recent shift in perspective proposes a more integrated approach for DTD, encompassing psychosocial, biological, and interactive factors. This multifactorial model calls for a multidisciplinary therapeutic intervention, not restricted to pharmacological treatments but also including psychotherapy, neurostimulation, and social interventions. Informing professionals and the general public about the significance of this new approach could mitigate the stigma associated with depression and enhance the quality of care. The future challenge will involve a deeper clinical understanding of DTD and its optimal management by refining available treatments.

Local neuroanatomical and tract-based proxies of optimal subcallosal cingulate deep brain stimulation

BACKGROUND

Deep brain stimulation of the subcallosal cingulate area (SCC-DBS) is a promising neuromodulatory therapy for treatment-resistant depression (TRD). Biomarkers of optimal target engagement are needed to guide surgical targeting and stimulation parameter selection and to reduce variance in clinical outcome.

OBJECTIVE/HYPOTHESIS

We aimed to characterize the relationship between stimulation location, white matter tract engagement, and clinical outcome in a large (n = 60) TRD cohort treated with SCC-DBS. A smaller cohort (n = 22) of SCC-DBS patients with differing primary indications (bipolar disorder/anorexia nervosa) was utilized as an out-of-sample validation cohort.

METHODS

Volumes of tissue activated (VTAs) were constructed in standard space using high-resolution structural MRI and individual stimulation parameters. VTA-based probabilistic stimulation maps (PSMs) were generated to elucidate voxelwise spatial patterns of efficacious stimulation. A whole-brain tractogram derived from Human Connectome Project diffusion-weighted MRI data was seeded with VTA pairs, and white matter streamlines whose overlap with VTAs related to outcome ('discriminative' streamlines; Puncorrected < 0.05) were identified using t-tests. Linear modelling was used to interrogate the potential clinical relevance of VTA overlap with specific structures.

RESULTS

PSMs varied by hemisphere: high-value left-sided voxels were located more anterosuperiorly and squarely in the lateral white matter, while the equivalent right-sided voxels fell more posteroinferiorly and involved a greater proportion of grey matter. Positive discriminative streamlines localized to the bilateral (but primarily left) cingulum bundle, forceps minor/rostrum of corpus callosum, and bilateral uncinate fasciculus. Conversely, negative discriminative streamlines mostly belonged to the right cingulum bundle and bilateral uncinate fasciculus. The best performing linear model, which utilized information about VTA volume overlap with each of the positive discriminative streamline bundles as well as the negative discriminative elements of the right cingulum bundle, explained significant variance in clinical improvement in the primary TRD cohort (R = 0.46, P < 0.001) and survived repeated 10-fold cross-validation (R = 0.50, P = 0.040). This model was also able to predict outcome in the out-of-sample validation cohort (R = 0.43, P = 0.047).

CONCLUSION(S)

These findings reinforce prior indications of the importance of white matter engagement to SCC-DBS treatment success while providing new insights that could inform surgical targeting and stimulation parameter selection decisions.

Irremediability in psychiatric euthanasia: examining the objective standard

BACKGROUND

Irremediability is a key requirement for euthanasia and assisted suicide for psychiatric disorders (psychiatric EAS). Countries like the Netherlands and Belgium ask clinicians to assess irremediability in light of the patient's diagnosis and prognosis and 'according to current medical understanding'. Clarifying the relevance of a default objective standard for irremediability when applied to psychiatric EAS is crucial for solid policymaking. Yet so far, a thorough examination of this standard is lacking.

METHODS

Using treatment-resistant depression (TRD) as a test case, through a scoping review in PubMed, we analyzed the state-of-the-art evidence for whether clinicians can accurately predict individual long-term outcome and single out irremediable cases, by examining the following questions: (1) What is the definition of TRD; (2) What are group-level long-term outcomes of TRD; and (3) Can clinicians make accurate individual outcome predictions in TRD?

RESULTS

A uniform definition of TRD is lacking, with over 150 existing definitions, mostly focused on psychopharmacological research. Available yet limited studies about long-term outcomes indicate that a majority of patients with long-term TRD show significant improvement over time. Finally, evidence about individual predictions in TRD using precision medicine is growing, but methodological shortcomings and varying predictive accuracies pose important challenges for its implementation in clinical practice.

CONCLUSION

Our findings support the claim that, as per available evidence, clinicians cannot accurately predict long-term chances of recovery in a particular patient with TRD. This means that the objective standard for irremediability cannot be met, with implications for policy and practice of psychiatric EAS.

The prevalence and economic burden of treatment-resistant depression in Thailand

BACKGROUND

The objectives of this study were to investigate the proportion of treatment-resistant depression (TRD) among patients with diagnosed major depressive disorder (MDD) and undergoing antidepressant treatment, to estimate the economic cost of MDD, TRD, and non-treatment-resistant depression (non-TRD), and to examine the differences between TRD and non-TRD MDD in a Thai public tertiary hospital.

METHODS

This was a combined study between retrospective review of medical records and a cross-sectional survey. The sample size was 500 dyads of antidepressant-treated MDD patients and their unpaid caregivers. MDD patients' medical records, the concept of healthcare resource utilization, the Work Productivity and Activity Impairment Questionnaire: depression and mood & mental state versions (WPAI: D, MM), the Class Impairment Questionnaire (CIQ), and the Family Experiences Interview Schedule (FEIS) were applied as the tools of the study. Pearson Chi's square, Fisher's Exact test, and independent T-test were employed for statistical analysis.

RESULTS

The proportion of TRD was 19.6% among antidepressant-treated MDD patients in a Thai tertiary public hospital. The results of the study indicated that several factors showed a statistically significant association with TRD criteria. These factors included younger age of MDD patients, a younger age of onset of MDD, lower body mass index (BMI), a history of suicide attempts and self-harm, as well as frequent smoking behavior. The annualized economic cost of TRD was 276,059.97 baht per person ($7,668.33), which was significantly higher than that of cost of non-TRD (173,487.04 baht or $4,819.08). The aggregated economic costs of MDD were 96.8 million baht annually ($2.69 M) if calculated from 500 MDD patients and unpaid caregivers. This contributed to the economic cost of TRD 27.05 million baht (98 respondents) and the economic cost of non-TRD 69.74 million baht (402 respondents).

CONCLUSIONS

The economic burden associated with TRD was significantly higher compared to non-TRD among antidepressant-treated MDD patients. Specifically, both direct medical costs and indirect costs were notably elevated in the TRD group.

Brain stimulation for treatment-resistant depression

Depression is one of the main public health problems in the world, having a high prevalence and being considered the main cause of disability. An important portion of patients does not respond to treatment with the initial trial of conventional antidepressants in the current depressive episode of moderate to severe intensity, which characterizes treatment-resistant depression. In this context, non-invasive neuromodulation procedures use an electric current or magnetic field to modulate the central nervous system, and they represent a new option for patients with treatment-resistant depression.

Immune Dysregulation in Treatment-Resistant Depression: Precision Approaches to Treatment Selection and Development of Novel Treatments

Owing to the link between immune dysfunction and treatment-resistant depression (TRD) and the overwhelming evidence that the immune dysregulation and major depressive disorder (MDD) are associated with each other, using immune profiles to identify the biological distinct subgroup may be the step forward to understanding MDD and TRD. This report aims to briefly review the role of inflammation in the pathophysiology of depression (and TRD in particular), the role of immune dysfunction to guide precision medicine, tools used to understand immune function, and novel statistical techniques.

Incidence of treatment-resistant depression during the first mood depressive episode

INTRODUCTION

In spite of several approaches and therapeutic measures, treatment-resistant depression (TRD) continues to inflict serious, individual and collective consequences. Therefore, there is a persistent need to scrutinize the concept of TRD in order to adapt the therapeutic strategies.

AIM

To estimate the incidence of TRD in patients with a first major depressive episode (MDD), and study factors associated with resistance.

METHODS

A descriptive prospective longitudinal study of outpatients with a first MDD, was conducted. Patients with a history of subthreshold hypomania were excluded. Eligible patients were put on a selective serotonin reuptake inhibitor (SSRI), either fluoxetine or sertraline. Participants were followed regularly until they had a therapeutic response or they met the criteria for TRD.

RESULTS

The study involved 82 adults. The incidence of treatment-resistant depression was 19.4% CI95%=[5.5-33.3]. Among the sociodemographic and clinical factors, family history of psychosis (p=0.038) and chronic respiratory comorbidities (p=0.016) were associated with TRD. The small size of the sample is a potential limitation of this study. Besides, the use of only two SSRIs could influence the results.

CONCLUSION

In this study, the incidence of TRD was at the lower limit of the rates reported in clinical studies. Clinical factors associated with TRD suggest the relevance of genotype analysis to identify patients with TRD. Furthermore, our results highlight the importance of heeding comorbidities to optimize care. Larger multicenter studies are needed to generalize.

Economic evaluation of interventions for treatment-resistant depression: A systematic review

Background

The extraordinarily high prevalence of treatment-resistant depression (TRD), coupled with its high economic burden to both healthcare systems and society, underscore how critical it is that resources are managed optimally to address the significant challenge it presents.

Objective

To review the literature on economic evaluation in TRD systematically, with the aim of informing future studies by identifying key challenges specific to the area, and highlighting good practices.

Methods

A systematic literature search across seven electronic databases was conducted to identify both within-trial and model-based economic evaluations in TRD. Quality of reporting and study design was assessed using the Consensus Health Economic Criteria (CHEC). A narrative synthesis was conducted.

Results

We identified 31 evaluations, including 11 conducted alongside a clinical trial and 20 model-based evaluations. There was considerable heterogeneity in the definition of treatment-resistant depression, although with a trend for more recent studies to use a definition of inadequate response to two or more antidepressive treatments. A broad range of interventions were considered, including non-pharmacological neuromodulation, pharmacological, psychological, and service-level interventions. Study quality as assessed by CHEC was generally high. Frequently poorly reported items related to discussion of ethical and distributional issues, and model validation. Most evaluations considered comparable core clinical outcomes - encompassing remission, response, and relapse. There was good agreement on the definitions and thresholds for these outcomes, and a relatively small pool of outcome measures were used. Resource criteria used to inform the estimation of direct costs, were reasonably uniform. Predominantly, however, there was a high level of heterogeneity in terms of evaluation design and sophistication, quality of evidence used (particularly health state utility data), time horizon, population considered, and cost perspective.

Conclusion

Economic evidence for interventions in TRD is underdeveloped, particularly so for service-level interventions. Where evidence does exist, it is hampered by inconsistency in study design, methodological quality, and availability of high quality long-term outcomes evidence. This review identifies a number of key considerations and challenges for the design of future economic evaluations. Recommendations for research and suggestions for good practice are made.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=259848&VersionID=1542096, identifier CRD42021259848.

Stigma as a barrier to early intervention among youth seeking mental health services in Ontario, Canada: a qualitative study

BACKGROUND

Stigma associated with mental health challenges is a major barrier to service seeking among youth. Understanding how stigma impacts service-seeking decisions from the perspectives of youth remains underexplored. Such research is necessary to inform effective stigma reduction.

OBJECTIVE

This study aims to understand how stigma influences service seeking among youth with mental health challenges.

METHODS

Qualitative inquiry was taken using youth engagement, underpinned by pragmatism. Data were collected via 4 virtual focus groups with 22 purposively selected youth participants with lived experience of mental health challenges in Ontario, Canada. Focus group guides were developed collaboratively among research team members, including youth co-researchers. Data were analyzed inductively using reflexive thematic analysis.

RESULTS

Three main themes were constructed from the data: point of entry into the system, being biomedicalized or trivialized, and paving the way for non-stigmatizing services. Initial contact with the mental healthcare system was seen to be affected by stigma, causing participants to delay contact or be refused services if they do not fit with an expected profile. Participants described a constant negotiation between feeling 'sick enough' and 'not sick enough' to receive services. Once participants accessed services, they perceived the biomedicalization or trivialization of their challenges to be driven by stigma. Lastly, participants reflected on changes needed to reduce stigma's effects on seeking and obtaining services.

CONCLUSION

A constant negotiation between being 'sick enough' or 'not sick enough' is a key component of stigma from the perspectives of youth. This tension influences youth decisions about whether to seek services, but also service provider decisions about whether to offer services. Building awareness around the invisibility of mental health challenges and the continuum of wellness to illness may help to break down stigma's impact as a barrier to service seeking. Early intervention models of care that propose services across the spectrum of challenges may prevent the sense of stigma that deters youth from accessing and continuing to access services.

Treatment patterns and healthcare utilization of patients with treatment-resistant depression estimated using health insurance database: A population-based study from Taiwan

BACKGROUND

Determining the proportion of patients with treatment-resistant depression (TRD) among patients with unipolar depression receiving adequate pharmacological treatment (pharmaceutically treated depression [PTD]) is clinically important and may affect health care utilization. In Taiwan, these issues can be assessed by analyzing population-based data.

METHODS

The present study included data from the Taiwan National Health Insurance Research Database from 2010 to 2017. Among patients with depression, PTD was defined by the receipt of at least one adequate antidepressant treatment, and TRD was defined as receiving a third adequate antidepressant treatment after failure to respond to two prior treatments. Time of progression from PTD to TRD was estimated via the Kaplan-Meier function. A propensity-matched case-comparison cohort approach was used to compare resource utilization between patients with non-TRD PTD and TRD.

RESULTS

TRD was defined in 11.2 % of patients with unipolar depression and 37.1 % of PTD patients. The time of progression from PTD to TRD was approximately 1 year. Most TRD patients were women, middle-aged, and treated in general practice clinics. Antidepressant monotherapy, followed by antidepressant with augmentation, was the most common treatment strategy applied to TRD patients. Medical utilization was significantly higher in patients with TRD than those with non-TRD PTD across most aspects.

LIMITATIONS

TRD was defined based on pharmacological treatment patterns, as the reasons for changes in antidepressant regimens were not available.

CONCLUSION

Approximately one-third of patients with PTD developed TRD, often soon after receiving adequate pharmacological treatment. Patients with TRD used more medical resources than patients with non-TRD PTD.

The Downstaging Concept in Treatment-Resistant Depression: Spotlight on Ketamine

Treatment-resistant depression is a pleomorphic phenomenon occurring in 30% of patients with depression. The chance to achieve remission decreases with every subsequent episode. It constitutes a significant part of the global disease burden, causes increased morbidity and mortality, and is associated with poor quality of life. It involves multiple difficult-to-treat episodes, with increasing resistance over time. The concept of staging captures the process of changes causing increasing treatment resistance and global worsening of functioning in all areas of life. Ketamine is a novel rapid-acting antidepressant with neuroplastic potential. Here, we argue that ketamine use as an add-on treatment of resistant major depressive disorder, based on its unique pharmacological properties, can reverse this process, give hope to patients, and prevent therapeutic nihilism.

Statins in depression: a repurposed medical treatment can provide novel insights in mental health

Depression has a large burden, but the development of new drugs for its treatment has proved difficult. Progresses in neuroscience have highlighted several physiopathological pathways, notably inflammatory and metabolic ones, likely involved in the genesis of depressive symptoms. A novel strategy proposes to repurpose established medical treatments of known safety and to investigate their potential antidepressant activity. Among numerous candidates, growing evidence suggests that statins may have a positive role in the treatment of depressive disorders, although some have raised concerns about possible depressogenic effects of these widely prescribed medications. This narrative review summarises relevant findings from translational studies implicating many interconnected neurobiological and neuropsychological, cardiovascular, endocrine-metabolic, and immunological mechanisms by which statins could influence mood. Also, the most recent clinical investigations on the effects of statins in depression are presented. Overall, the use of statins for the treatment of depressive symptoms cannot be recommended based on the available literature, though this might change as several larger, methodologically robust studies are being conducted. Nevertheless, statins can already be acknowledged as a driver of innovation in mental health, as they provide a novel perspective to the physical health of people with depression and for the development of more precise antidepressant treatments.

Irremediable Psychiatric Suffering in The Context of Medical Assistance in Dying: A Delphi-Study

OBJECTIVE

Patients with a psychiatric disorder are eligible to request medical assistance in dying (MAID) in a small but growing number of jurisdictions, including the Netherlands and Belgium. In Canada, MAID for mental illness will become possible in 2023. For this request to be granted, most of these jurisdictions demand that the patient is competent in her request, and that the suffering experienced is unbearable and irremediable. Especially the criterion of irremediability is challenging to establish in patients with psychiatric disorders. The aim of this research is to establish what criteria Dutch and Belgian experts agree to be necessary in characterising irremediable psychiatric suffering (IPS) in the context of MAID.

METHODS

A two-round Delphi procedure among psychiatrists with relevant experience.

RESULTS

Thirteen consensus criteria were established: five diagnostic and eight treatment-related criteria. Diagnostically, the participants deem a narrative description and attention to contextual and systemic factors necessary. Also, a mandatory second opinion is required. The criteria concerning treatment show that extensive biopsychosocial treatment is needed, and the suffering must be present for several years. Finally, in the case of refusal, the participants agree that there are limits to the number of diagnostic procedures or treatments a patient must undergo.

CONCLUSIONS

Consensus was found among a Dutch and Belgian expert group on potential criteria for establishing IPS in the context of MAID. These criteria can be used in clinical decision-making and can inform future procedural demands and research.

Comparative study of low-dose ketamine infusion and repetitive transcranial magnetic stimulation in treatment-resistant depression: A posthoc pooled analysis of two randomized, double-blind, placebo-controlled studies

BACKGROUND

This posthoc analysis compared the antidepressant and antisuicidal effects of low-dose ketamine infusion with those of repetitive transcranial magnetic stimulation (rTMS) on treatment-resistant depression (TRD).

METHODS

In the ketamine infusion trial, 48 patients with TRD were randomized to receive a single infusion of 0.5 mg/kg ketamine or normal saline. In the rTMS trial, 105 patients were randomly assigned to intermittent theta-burst stimulation (iTBS), 10-Hz rTMS, or sham stimulation. The 17-item Hamilton Rating Scale for Depression (HDRS) was administered.

RESULTS

The antidepressant effect was prominent at Day 7 postinfusion in the ketamine group but steadily accumulated with the treatment duration from Day 7 to 14 in the iTBS and 10-Hz rTMS groups, regardless of the level of treatment resistance (all p < .01). Low-dose ketamine infusion and iTBS exerted superior effects on suicidal symptoms (HDRS item 3) than the other three groups (p < .001). The antidepressant effect of iTBS/10-Hz rTMS may persist for up to 3 months; however, the antidepressant effect of a single low-dose ketamine infusion did not persist over a month.

DISCUSSION

Both low-dose ketamine infusion and rTMS/TBS must be included in TRD treatment but may be applied in different clinical situations.

Optimal dose of brexpiprazole for augmentation therapy of antidepressant-refractory depression: A systematic review and dose-effect meta-analysis

BACKGROUND

Brexpiprazole augmentation is an effective treatment strategy for antidepressant-refractory depression, but its optimal dosage remains unclear.

AIMS

To find the optimal dosage of brexpiprazole as augmentation of other antidepressants.

METHODS

We searched multiple electronic databases (from inception to September 16th, 2021) to identify double-blind, randomized placebo-controlled fixed-dose trials evaluating brexpiprazole augmentation therapy in adults (≥18 years old, both genders) with major depressive disorder not adequately responding to one or more antidepressant treatment. Our outcomes of interest at 8 weeks (range 4-12 weeks) were efficacy (treatment response defined as 50% or greater reduction in depression severity), tolerability (dropouts due to adverse effects) and acceptability (dropouts for any reason). We performed a random-effects, one-stage dose-effect meta-analysis with restricted cubic splines.

RESULTS

Six studies met the inclusion criteria, including 1671 participants in total. The dose-efficacy curve showed an increase up to doses around 2 mg (odds ratio [OR] 1.52, 95% confidence interval [CI] 1.12-2.06) and then a decreasing trend through the higher licensed dose up to 3 mg (OR 1.40, 95% CI 0.95-2.08). The shape of the dose-tolerability curve was comparable to that of the efficacy and the dose-acceptability curve showed a monotonic increasing trend but both had wide confidence bands.

CONCLUSIONS

One to two milligrams of brexpiprazole as augmentation treatment may achieve an optimal balance between efficacy, tolerability, and acceptability in the acute treatment of antidepressant-refractory depression. However, the small number of included studies limit the reliability of the results. Further research is required to validate the findings.

Prognostic Significance of Blood-Based Baseline Biomarkers in Treatment-Resistant Depression: A Literature Review of Available Studies on Treatment Response

Major depressive disorder is a leading cause of disability worldwide and a major contributor to the overall global burden of disease. While there are several options for antidepressant treatment, only about 40–60% of patients respond to initial monotherapy, while 30–40% of patients may even show resistance to treatment. This article offers a narrative review of those studies evaluating the predictive properties of various blood-based baseline biomarkers regarding treatment responses to the pharmacological, stimulation, or behavioral treatment of patients with treatment-resistant depression (TRD). Our results show that overall, there is only a very limited number of studies assessing baseline peripheral biomarkers regarding treatment response in TRD. Although there is some evidence for the predictive significance of particular biomarkers (e.g., IL-6, CRP, BDNF), the majority of the results are either single-study reports or studies with conflicting results. This may contribute to the wide variety of treatment protocols and different TRD definition criteria, the small number of patients included, and the existence of different biological phenotypes of the disorder used within the various studies. Taken together, there does not yet appear to be any specific baseline peripheral biomarker with sufficient discriminative predictive validity that can be used in the routine clinical practice of TRD. The discovery of new biomarkers and the better clinical characterization of known biomarkers could support the better classification and staging of TRD, the development of personalized treatment algorithms with higher rates of remission and fewer side effects, and the development of new precision drugs for specific subgroups of patients.

Treatment of difficult-to-treat depression - clinical guideline for selected interventions

BACKGROUND

Difficult-to-treat-depression (DTD) is a clinical challenge. The interventions that are well-established for DTD are not suitable or effective for all the patients. Therefore, more treatment options are highly warranted. We formulated an evidence-based guideline concerning six interventions not well-established for DTD in Denmark.

METHODS

Selected review questions were formulated according to the PICO principle with specific definitions of the patient population (P), the intervention (I), the comparison (C), and the outcomes of interest (O), and systematic literature searches were performed stepwise for each review question to identify relevant systematic reviews/meta-analyses, and randomized controlled trials. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) system was used to assess the methodological quality of the included studies. Clinical recommendations were formulated based on the evidence, the risk-benefit ratio, and perceived patient preferences.

RESULTS

We found sufficient evidence for a weak recommendation of repetitive transcranial magnetic stimulation (rTMS) and cognitive behavioural analysis system of psychotherapy (CBASP). The use of bright light therapy in DTD was not sufficiently supported by the evidence, but should be considered as good clinical practice. The interventions should be considered in addition to ongoing antidepressant treatment. We did not find sufficient evidence to recommend intravenous ketamine/esketamine, rumination-focused psychotherapy, or cognitive remediation to patients with DTD.

CONCLUSION

The evidence supported two of the six reviewed interventions, however it was generally weak which emphasizes the need for more good quality studies. This guideline does not cover all treatment options and should be regarded as a supplement to relevant DTD-guidelines.

Low-dose ketamine infusion in treatment-resistant double depression: Revisiting the adjunctive ketamine study of Taiwanese patients with treatment-resistant depression

BACKGROUND

Whether a single low-dose ketamine infusion may have rapid antidepressant and antisuicidal effects in patients with treatment-resistant double depression remains unclear.

METHODS

This study enrolled 35 patients with treatment-resistant double depression, 12 of whom received 0.5 mg/kg ketamine, 11 received 0.2 mg/kg ketamine, and 12 received normal saline as a placebo. The patients were assessed using the 17-item Hamilton Rating Scale for Depression (HDRS) prior to the initiation of infusions, at 40 and 240 min post-infusion, and sequentially on Days 2-7 and on Day 14 after ketamine or placebo infusions.

RESULTS

A single 0.5 mg/kg ketamine infusion had rapid antidepressant (p = 0.031, measured by the HDRS) and antisuicidal (p = 0.033, measured by the HDRS item 3 scores) effects in patients with treatment-resistant double depression. However, 0.2 mg/kg ketamine was insufficient to exert rapid antidepressant and antisuicidal effects in this patient population with severe and chronic illness.

DISCUSSION

In this patient population, the commonly used dose of 0.5 mg/kg was sufficient. Additional studies are required to investigate whether repeated infusions of low-dose ketamine may also maintain antidepressant and antisuicidal effects in patients with treatment-resistant double depression.

Transdiagnostic Symptom Subtypes to Predict Response to Therapeutic Transcranial Magnetic Stimulation in Major Depressive Disorder and Posttraumatic Stress Disorder

The diagnostic categories in psychiatry often encompass heterogeneous symptom profiles associated with differences in the underlying etiology, pathogenesis and prognosis. Prior work demonstrated that some of this heterogeneity can be quantified though dimensional analysis of the Depression Anxiety Stress Scale (DASS), yielding unique transdiagnostic symptom subtypes. This study investigated whether classifying patients according to these symptom profiles would have prognostic value for the treatment response to therapeutic transcranial magnetic stimulation (TMS) in comorbid major depressive disorder (MDD) and posttraumatic stress disorder (PTSD). A linear discriminant model was constructed using a simulation dataset to classify 35 participants into one of the following six pre-defined symptom profiles: Normative Mood, Tension, Anxious Arousal, Generalized Anxiety, Anhedonia and Melancholia. Clinical outcomes with TMS across MDD and PTSD were assessed. All six symptom profiles were present. After TMS, participants with anxious arousal were less likely to achieve MDD remission compared to other subtypes (FET, odds ratio 0.16, p = 0.034), exhibited poorer PTSD symptom reduction (21% vs. 46%; t (33) = 2.025, p = 0.051) and were less likely to complete TMS (FET, odds ratio 0.066, p = 0.011). These results offer preliminary evidence that classifying individuals according to these transdiagnostic symptom profiles may offer a simple method to inform TMS treatment decisions.

Treatment-Resistant Depression in Portugal: Perspective From Psychiatry Experts

Guidance about treatment-resistant depression (TRD) in Portugal is very limited, even though depression prevalence is among the highest in European countries. A questionnaire was conducted, followed by two advisory boards with seven Portuguese psychiatry experts, to characterize and discuss MDD and TRD epidemiology, diagnosis, patient journey, treatment options, and unmet clinical needs. Consensus was reached on the main issues. In daily practice, TRD can be defined as moderate to severe MDD episodes with insufficient clinical improvement after two antidepressant treatments, taken in adequate doses and duration. TRD diagnosis and treatment are mostly decided by psychiatrists at public hospitals. Treatment type and duration must be adjusted to characteristics of the patient and the depressive episode, including symptoms, number of previous episodes, comorbidities, and previous treatment response and side effects. The most relevant objectives of TRD treatment are reaching response and remission, prevention of suicide, and improvement of quality of life, functionality, and wellbeing. Regarding pharmacotherapy, antidepressant switch occurs more frequently with non-response, while optimization, combination, and augmentation are considered for patients with partial response. Psychotherapy should be considered in parallel to pharmacological treatment. Brain stimulation techniques are underused. Lifelong treatment is required for recurrent or more chronic TRD episodes, but patient adherence is also poorer in these cases. In Portugal, TRD management is limited by lack of access to specialist care and to many treatment options. These aspects highlight that conventional pharmacotherapy does not lead to remission in many patients and that optimization strategies are frequently necessary to achieve satisfactory treatment outcomes.

Is one or two infusions better in the first week of low-dose ketamine treatment for medication-resistant depression? A post hoc pooled analysis of randomized placebo-controlled and open-label trials

BACKGROUND

Whether a second ketamine infusion in the first week improves the antidepressant, antisuicidal, and anti-inflammatory effects of the first low-dose ketamine infusion remains unclear.

METHODS

A total of 78 patients with medication-resistant depression were allocated to receive two ketamine infusions (n = 30; days 1 and 4), a single ketamine infusion (n = 24; only day 1), or normal saline placebo infusion (n = 24; only day 1). The Montgomery-Asberg Depression Scale (MADRS) and 17-item Hamilton Rating Scale for Depression (HDRS) were administered before and at 40 min, 240 min, day 2, day 4, day 5, and day 7 after infusion. Serum concentrations of interleukin (IL)-2 and tumor necrosis factor (TNF)-α were assessed.

RESULTS

Two ketamine infusions improved the overall depressive symptoms (p < 0.001) and melancholic symptoms (p < 0.001) than a single ketamine or placebo infusion. The antisuicidal effect did not differ between the ketamine treatment groups. Two ketamine infusions increased TNF-α levels compared with a single ketamine or placebo infusion (p = 0.015). A single ketamine infusion improved the TNF-α-to-IL-2 ratio, an index of average anti-inflammatory effect, than two ketamine infusions or a single placebo infusion (p = 0.027).

DISCUSSION

Repeated low-dose ketamine infusions improved the antidepressant effect, but not the antisuicidal effect, compared with a single infusion. However, repeated ketamine infusions may exert a lesser anti-inflammatory effect than a single infusion.

Economic impact of treatment-resistant depression: A retrospective observational study

BACKGROUND

To determine the incidence of Treatment-Resistant Depression (TRD) in Spain and to estimate its economic burden, using real world data.

METHODS

A retrospective, observational-study was carried out using data from the BIG-PAC database®. Patients aged ≥18 years with a diagnosis of major depressive-disorder (MDD) who initiated a new antidepressant treatment in 2015-2017 were included. The patients were classified as TRD and non-TRD. Patients were classified as TRD if they had, during the first year of antidepressant treatment: a) failure with ≥2 antidepressants including the prescription of ≥3 antidepressants (N06A) or ≥2 antidepressant and ≥1 antipsychotic (N05A; including lithium) b) antidepressants administered for ≥ 4 weeks each, and c) the time between the end of one treatment and the initiation of the next was ≤ 90 days. Inherent limitations of data collection from databases should also be considered in this analysis (e.g., lack of information about adherence to treatment). Follow-up period: 18 months. The incidence rate was calculated as the number of TRD patients per 1,000 persons-year divided by the population attended.

OUTCOMES

direct healthcare and indirect costs. Two sensitivity analyses were performed varying the index date and the period used to define TRD patients (6 vs.12 months).

RESULTS

21,630 patients with MDD aged ≥ 18 years (mean age: 53.2 years; female: 67.2%) were analyzed, of whom 3,559 met TRD criteria, yielding a 3-year cumulative incidence of 16.5% (95%CI: 16%-17%) among MDD patients. The annual population incidence rate of TRD in 2015-2017, was 0.59, 1.02 and 1.18/1,000 person-years, respectively (mean: 0.93/1,000 person-year). Overall, mean total costs per MDD patient were €4,147.9, being higher for TRD than for non-TRD patients (€6,096 vs. €3,846; p<0.001): a) direct costs (€1,341 vs. €624; p<0.001), b) lost productivity (€1,274 vs. €821; p<0.001) and c) permanent disability (€3,481 vs. €2,401; p<0.001, adjusted). Sensitivity analyses showed no differences with the reported results.

CONCLUSIONS

The population based TRD incidence in Spain was similar to recent data from other European countries. TRD is associated with greater resource use and higher costs compared with non-TRD patients.

Polymorphisms of COMT and CREB1 are associated with treatment-resistant depression in a Chinese Han population

Genetic factors play a crucial role for the pathophysiology of treatment-resistant depression (TRD). It has been established that Catechol-O-methyltransferase (COMT) and cyclic amp-response element-binding protein (CREB) are associated with antidepressant response. The aim of this study was to explore the association between single nucleotide polymorphisms (SNPs) in COMT and CREB1 genes and TRD in a Chinese population. We recruited 181 patients with major depressive disorder (MDD) and 80 healthy controls, including 81 TRD patients. Depressive symptoms were assessed with the Hamilton Depression Rating Scale-17 (HDRS). Genotyping was performed using mass spectrometry. Genetic analyses were conducted by PLINK Software. The distribution of COMT SNP rs4818 allele and genotypes were significantly different between TRD and controls. Statistical differences in allele frequencies were observed between TRD and non-TRD groups, including rs11904814 and rs6740584 in CREB1 gene, rs4680 and rs4818 in COMT gene. There were differences in the distribution of HDRS total scores among different phenotypes of CREB1 rs11904814, CREB1 rs6740584, COMT rs4680 and rs4818. Gene-gene interaction effect of COMT-CREB1 (rs4680 × rs6740584) revealed significant epistasis in TRD. There findings indicate that COMT and CREB1 polymorphisms influence the risk of TRD and affect the severity of depressive symptoms of MDD.

Effects of treatment refractoriness and brain-derived neurotrophic factor Val66Met polymorphism on antidepressant response to low-dose ketamine infusion

Evidence suggests that levels of treatment refractoriness and brain-derived neurotrophic factor (BDNF) rs6265 polymorphism are related to the antidepressant effects of conventional antidepressants and repetitive transcranial magnetic stimulation. However, whether these factors are associated with the antidepressant effects of low-dose ketamine remains unclear. In total, 71 patients with treatment-resistant depression (TRD) were randomized to 0.5 mg/kg ketamine, 0.2 mg/kg ketamine, and saline control infusion groups. They were further divided into three treatment refractoriness groups according to the Maudsley staging method and were genotyped for Val66Met BDNF polymorphism. Participants' Hamilton Depression Rating Scale (HDRS) scores were assessed preinfusion, at 40, 80, 120, and 240 min postinfusion, and sequentially on days 2-7 and 14 after infusion. Patients with any Val allele exhibited an antidepressant response (p = 0.029) to 0.5 mg/kg ketamine vs. 0.2 mg/kg ketamine vs. saline control infusions. However, the trajectory of HDRS scores did not differ (p = 0.236) between the treatment groups among Met/Met carriers. In the low treatment refractoriness group, the 0.2 mg/kg ketamine infusion exhibited the optimal antidepressant effect (p = 0.002); in the moderate treatment refractoriness group, the 0.5 mg/kg ketamine infusion achieved the strongest antidepressant effect (p = 0.006); however, in the high treatment refractoriness group, the trajectory of depressive symptoms did not differ between treatments (p = 0.325). In future clinical practice, ketamine dose may be adjusted according to the level of treatment refractoriness and BDNF rs6265 polymorphism to achieve the optimal antidepressant effect for patients with TRD.

Baseline Working Memory Predicted Response to Low-Dose Ketamine Infusion in Patients with Treatment-Resistant Depression

INTRODUCTION

Pretreatment neurocognitive function may predict the treatment response to low-dose ketamine infusion in patients with treatment-resistant depression (TRD). However, the association between working memory function at baseline and the antidepressant efficacy of ketamine infusion remains unclear.

METHODS

A total of 71 patients with TRD were randomized to one of three treatment groups: 0.5 mg/kg ketamine, 0.2 mg/kg ketamine, or normal saline. Depressive symptoms were measured using the 17-item Hamilton Depression Rating Scale (HDRS) at baseline and after treatment. Cognitive function was evaluated using working memory and go-no-go tasks at baseline.

RESULTS

A generalized linear model with adjustments for demographic characteristics, treatment groups, and total HDRS scores at baseline revealed only a significant effect of working memory function (correct responses and omissions) on the changes in depressive symptoms measured by HDRS at baseline (F=12.862, p<0.05). Correlation analysis further showed a negative relationship (r=0.519, p=0.027) between pretreatment working memory function and changes in HDRS scores in the 0.5 mg/kg ketamine group.

DISCUSSION

An inverse relationship between pretreatment working memory function and treatment response to ketamine infusion may confirm that low-dose ketamine infusion is beneficial and should be reserved for patients with TRD.

Pathophysiology of Major Depression by Clinical Stages

The comprehension of the pathophysiology of the major depressive disorder (MDD) is essential to the strengthening of precision psychiatry. In order to determine the relationship between the pathophysiology of the MDD and its clinical progression, analyzed by severity of the depressive symptoms and sleep quality, we conducted a study assessing different peripheral molecular biomarkers, including the levels of plasma C-reactive protein (CRP), serum mature brain-derived neurotrophic factor (mBDNF), serum cortisol (SC), and salivary cortisol awakening response (CAR), of patients with MDD (n = 58) and a control group of healthy volunteers (n = 62). Patients with the first episode of MDD (n = 30) had significantly higher levels of CAR and SC than controls (n = 32) and similar levels of mBDNF of controls. Patients with treatment-resistant depression (TRD, n = 28) presented significantly lower levels of SC and CAR, and higher levels of mBDNF and CRP than controls (n = 30). An increased severity of depressive symptoms and worse sleep quality were correlated with levels low of SC and CAR, and with high levels of mBDNF. These results point out a strong relationship between the stages clinical of MDD and changes in a range of relevant biological markers. This can assist in the development of precision psychiatry and future research on the biological tests for depression.

Treatment-resistant bipolar depression: concepts and challenges for novel interventions

Treatment-resistant bipolar depression (TRBD) has been reported in about one-quarter of patients with bipolar disorders, and few interventions have shown clear and established effectiveness. We conducted a narrative review of the published medical literature to identify papers discussing treatment-resistant depression concepts and novel interventions for bipolar depression that focus on TRBD. We searched for potentially relevant English-language articles published in the last decade. Selected articles (based on the title and abstract) were retrieved for a more detailed evaluation. A number of promising new interventions, both pharmacological and non-pharmacological, are being investigated for TRBD treatment, including ketamine, lurasidone, D-cycloserine, pioglitazone, N-acetylcysteine, angiotensin-converting enzyme inhibitors, angiotensin II type 1 receptor blockers, cyclooxygenase 2 inhibitors, magnetic seizure therapy, intermittent theta-burst stimulation, deep transcranial magnetic stimulation, vagus nerve stimulation therapy, and deep brain stimulation. Although there is no consensus about the concept of TRBD, better clarification of the neurobiology associated with treatment non-response could help identify novel strategies. More research is warranted, mainly focusing on personalizing current treatments to optimize response and remission rates.

Interest-activity symptom severity predicts response to ketamine infusion in treatment-resistant depression

BACKGROUND

Interest and activity are part of the positive mood domain. Evidence suggests the symptom domain of interest-activity at baseline as a clinical predictor for treatment response to traditional antidepressants. However, whether this domain is related to the response to a single low-dose ketamine infusion remains unclear.

METHODS

Seventy-one patients with treatment-resistant depression were randomized to 3 treatment groups: a single 0.5 or 0.2 mg/kg ketamine or normal saline placebo infusion. Depressive symptoms were measured using the 17-item Hamilton Depression Rating Scale before infusions and at postinfusion period (at 40 min and up to 2 weeks). Low (mild) versus medium versus high (severe) interest-activity symptom domain groups were classified on the basis of the cutoff point of ± 0.4 standard deviation. The effect of baseline interest-activity symptoms on outcomes was tested using generalized estimating equation models.

RESULTS

The interest-activity symptom domain as a continuous variable (β = 8.413, p = .016) was related to the trajectory of depressive symptoms. Stratified by levels of the interest-activity symptom domain, in the low interest-activity, 0.2 mg/kg ketamine infusion (β = 0.013) demonstrated the greatest antidepressant effect (p < .01) compared with 0.5 mg/kg ketamine (β = 0.739) and placebo infusions; however, in the high interest-activity, 0.5 mg/kg ketamine infusion (β = 0.001) demonstrated the best antidepressant effect (p < .01) compared with 0.2 mg/kg ketamine (β = 1.372) and placebo infusions.

DISCUSSION

The symptom domain of interest-activity was an independent predictor for the treatment response to a single low-dose ketamine infusion.

Irremediable Psychiatric Suffering in the Context of Physician-assisted Death: A Scoping Review of Arguments: La souffrance psychiatrique irrémédiable dans le contexte du suicide assisté : Une revue étendue des arguments

OBJECTIVES

Physician-assisted death (PAD), also known as medical assistance in dying, of patients with a psychiatric disorder (PPD) is a global issue of debate. In most jurisdictions that allow PAD, irremediable suffering is a legal requirement, how to apply the concept of irremediability to PPD remains challenging. The aim of this article is to identify the main arguments concerning irremediability in the debate about PAD of PPD and give directions for further moral deliberation and empirical research.

METHODS

Systematic searches in MEDLINE, Embase, and PsycINFO were combined with 4 additional search strategies. All conceptual-ethical articles, quantitative and qualitative empirical studies, guidelines, case reports, and commentaries that met the inclusion criteria were included, and a qualitative data synthesis was used to identify recurring themes within the literature. The study protocol was preregistered at the Open Science Framework under registration code: thjg8.

RESULTS

A total of 50 articles met the inclusion criteria. Three main arguments concerning irremediability were found in the debate about PAD of PPD: uncertainty, hope, and treatment refusal.

CONCLUSIONS

Uncertainty about irremediability is inevitable, so which level of certainty is morally required should be the subject of moral deliberation. Whether PAD induces or resolves hopelessness is an empirical claim that deserves clarification. Treatment refusal in search of PAD raises questions about treatment efficacy in this patient group and about decision-making in the context of the physician-patient relationship. Going forward, more attention should be given to epidemiological research and to specific challenges posed by different psychiatric disorders.

Could ketamine be the answer to treating treatment-resistant major depressive disorder?

Major depressive disorder (MDD) is a common, serious, debilitating condition affecting 350 million people worldwide, which remains to be unsatisfactorily treated with 53% of patients still complaining of symptoms after completing their courses with the correct dosage. Ketamine, which was approved by the Food and Drug Administration in 2019, is a potential treatment option for those recalcitrant cases. The mechanism of ketamine is not fully understood, but as type it is classified as an N-methyl-D-aspartate (NMDA) glutamate receptor antagonist, and can be given intravenously, intranasally and orally. It is used to treat treatment-resistant depression, depression associated with suicidal ideation, mood and anxiety disorders and depressions associated with either type of bipolar disorder. Although ketamine is considered relatively safe, several side effects have been reported with the major ones being psychiatric in the form of worsening mood, anxiety and agitation; psychotomimetic in the form of dissociation, perceptual disturbance and abnormal sensations; cardiovascular in the form of increased blood pressure and increased heart rate; and neurological in the form of headache and dizziness. Ketamine is still not approved worldwide for usage in patients with treatment-resistant MDD, but if it is approved sometime in the future with relatively fewer side effects, it is expected to significantly save millions of dollars spent yearly on patients with treatment-resistant depression and that will lift this major burden off the shoulders of healthcare professionals. This study was designed to measure the effects of ketamine, an NMDA receptor antagonist, on patients with treatment-resistant MDD and to analyse the concept that makes it different and relatively safer than other major antidepressants like selective serotonin reuptake inhibitors, monoamine oxidase inhibitors and TCAs (tricyclic antidepressants).

Evaluation of the effects of rTMS on self-reported quality of life and disability in treatment-resistant depression: A THREE-D study

INTRODUCTION

Although the antidepressant efficacy of rTMS is well documented, patient reported outcomes (PROs) with rTMS are poorly characterized. The aim of the current study is to assess short and long-term changes in self-reported quality of life and disability following a 6-week course of rTMS.

METHODS

We performed a secondary analysis of data from the multi-centre THREE-D trial of 10 Hz high-frequency (HF) rTMS (n = 192) vs. intermittent theta-burst stimulation (iTBS) (n = 193) of the left dorsolateral prefrontal cortex (DLPFC). We assessed changes in the Quality of Life Enjoyment and Satisfaction Questionnaire and Sheehan Disability Scale pre-treatment, at 1-week post-rTMS treatment (Acute Follow-up), and at 12-weeks post-treatment (Long-Term Follow-Up).

RESULTS

PROs significantly improved with rTMS. There were no differences in PROs between iTBS and HF left DLPFC rTMS at either the Acute or Long-Term Follow-Up. The magnitude of the change in effect sizes seen for the PROs were significantly greater in those who achieved greater resolution their depressive symptoms, with remitters demonstrating very large effect size improvements in PROs compared to small-to-medium effect sizes in non-remitters.

CONCLUSIONS

This study is the largest in the literature exploring at the effect of rTMS on PROs. rTMS yielded acute and sustained improvements in PROs. The improvements in PROs were strongly associated with the degree of resolution of depressive symptoms. The magnitude of the change in remitters was comparable to those reported with ECT. The goal of a course of rTMS should be for full remission of depressive symptoms in order to achieve optimal functional outcomes.

Ketamine: Leading us into the future for development of antidepressants

Numerous randomized double-blind clinical trials have consistently shown that that a single intravenous administration of a subanesthetic dose of ketamine to treatment-resistant depressed patients significantly improved depressive symptomatology rapidly, within two hours, with the effect lasting up to seven days. Despite its very promising effects, ketamine has long been associated with potential for abuse as it can cause psychotropic side effects, such as hallucinations, false beliefs, and severe impairments in judgment and other cognitive processes. Consequently, within the last two decades preclinical research has been carried out aimed at understanding its mechanisms of action and the brain circuits involved in ketamine's antidepressant effects, both of which are discussed in this review. Furthermore, with the hippocampus being a key target for ketamine's beneficial antidepressant effects, we and others have begun to examine behavioral and neurochemical effects of drugs that act selectively on the hippocampus due to the preferential location of their receptor targets. Such drugs are negative allosteric modulators (NAMs) and positive allosteric modulator (PAM) of the α5-GABA_A receptor. Such compounds are discussed within the framework of how lessons learned with ketamine point to novel classes of drugs, targeting the GABAergic system, that can recapitulate the antidepressant effects of ketamine without its adverse effects.