Results of the European Group for the Study of Resistant Depression (GSRD) - basis for further research and clinical practice

Comparison between accelerated and standard or sham rTMS in the treatment of depression: A systematic review

Major depressive disorder (MDD) represents a major global health challenge, with a significant proportion of patients being resistant to drug treatment (TRD). Repetitive transcranial magnetic stimulation (rTMS) has shown promise in the treatment of MDD/TRD, with a single stimulation session per day for five days per week over several weeks (the "standard" protocol). The two main paradigms used are high-frequency rTMS and intermittent theta burst stimulation (iTBS) delivered to the left dorsolateral prefrontal cortex (DLPFC). Accelerated TMS (aTMS) protocols aim to make the treatment more effective, or at least more rapidly effective, by delivering more stimulations in a shorter time, which could also facilitate the implementation of the protocols for a larger number of patients. In this systematic literature review, articles comparing in the same study an aTMS protocol to a standard or sham rTMS protocol were retained for analysis. Thus, 23 articles were retained and the analysis focused on the efficacy of aTMS protocols used for the treatment of depression (MDD/TRD) as well as on the impact of various stimulation parameters, such as stimulation pattern, intersession interval, dosage, and methods of cortical targeting. Although some studies did not report significant differences between aTMS and standard or sham protocols, others suggested potential advantages of aTMS, such as twice-daily HF-rTMS of the left DLPFC or more intensive iTBS protocols with a long interval between two sessions and personalized cortical targeting. Our results highlight the influence of the number of sessions or pulses per session (dosage), the duration of the interval between sessions, and the precision of target localization (using image-guided neuronavigation) on therapeutic efficacy. However, limitations in sample size, few independent studies replicating the same methodology, and variability in the clinical profile of treated patients, given different definitions of treatment resistance or the presence of comorbidities, hamper definitive conclusions.

HPA axis in psychotic and non-psychotic major depression: Cortisol plasma levels and hippocampal volume

BACKGROUND

Psychotic major depression (PMD) differs from non-psychotic MD (NPMD) in psychopathology and is linked to changes in brain volumetry and hypothalamic-pituitary-adrenal (HPA) axis function that can be reflected by its principal output - the glucocorticoid cortisol. NPMD patients exhibit smaller hippocampi than healthy controls (HC), purportedly representing exposure to chronic stress. However, the relationship between the individual clinical phenotype, hippocampal volume and diurnal cortisol signaling remains unclear.

METHODS

Since understanding the interplay among symptoms, neuroimaging and HPA function is crucial for discerning biological differences between PMD and NPMD, this study explored the link between clinical phenotype, hippocampal structural MRI and circadian plasma cortisol levels in 32 HC, 27 NPMD and 26 PMD patients.

RESULTS

PMD patients showed significantly elevated evening (6 p.m. - 1 a.m.) cortisol levels compared to NPMD and HC, while NPMD and HC did not differ. No group differences in hippocampal volume were observed, but a significant interaction effect emerged between overnight (1 a.m. - 9 a.m.) cortisol levels, hippocampal volume, and clinical phenotype. NPMD patients displayed a negative correlation between overnight cortisol levels and hippocampal volume, which was specific to the ascending cortisol curve (2 a.m. - 5 a.m.) and absent in PMD and HC. The hippocampus-cortisol interaction was associated with depressive symptom severity in NPMD but not PMD, where cortisol alone predicted greater severity.

CONCLUSIONS

These findings imply a time-dependent relationship between hippocampal volume and overnight cortisol in NPMD, which is absent in PMD and HC. In contrast, PMD patients exhibited increased evening cortisol levels. In an exploratory analysis, these effects were also related to symptom severity at similar timepoints. While correlational, these results point to distinct neurobiological mechanisms underlying NPMD and PMD, which are potentially related to the heterogeneous clinical manifestations.

Specific symptomatology profile associated with treatment resistant depression: A multicentric study from the Group for the Study of Resistant Depression with a focus on sex

BACKGROUND

Clinical predictors of treatment-resistant depression could improve treatment strategies. Depressive symptom profiles at baseline are potential outcome predictors, but little evidence is available, and sex-specific profiles have been scarcely investigated.

METHODS

Baseline symptom scores of 1294 patients with major depressive disorder were assessed by the Montgomery-Åsberg depression rating scale (MADRS) as part of a multicenter study by the "Group for the Studies of Resistant Depression". Treatment outcomes were assessed according to the MADRS after ≥4 weeks of naturalistic treatment. We tested if individual MADRS item scores at baseline were associated with treatment outcome in the whole sample and in sex-stratified subgroups.

RESULTS

A specific baseline symptom profile was associated with non-response in the whole sample. In particular, apparent and reported sadness, reduced sleep, lassitude, inability to feel, and pessimistic thoughts were the only MADRS items that scored higher at baseline in patients with subsequent lack of response. In the sex-stratified analysis, females showed a similar profile overall, however they showed higher baseline levels of inner tension, inability to feel, and pessimistic thoughts compared to males, and these symptoms were associated with lack of response in females but not in males. Neurovegetative symptoms were poorly predictive. Overall baseline severity related to poor response.

LIMITATIONS

This is a post-hoc analysis. The naturalistic design of the study with a retrospective assessment is potential limitations.

CONCLUSION

A specific baseline symptom profile characterized by higher sadness, reduced sleep and anhedonic features may be indicative of poor treatment outcome. Females showed a distinctive baseline profile associated with poor response.

Emerging strategies and clinical recommendations for the management of novel depression subtypes

INTRODUCTION

The phenomenology of depression is characterized by a wide array of emotional, cognitive, and physical symptoms that significantly disrupt an individual's life. Societal changes, driven by technological advancements, economic pressures, environmental concerns including climate change, and shifting cultural norms, have influenced how depression manifests and is understood. These developments have led to the identification of new depression subtypes, highlighting the need for personalized treatment approaches based on individual symptoms and underlying causes.

AREAS COVERED

The authors provide a comprehensive narrative review of the literature on managing novel depression subtypes, focusing on both pharmacological and non-pharmacological treatments. Specifically, scenarios recorded were related to i) depression in adolescents and young adults; ii) depression and social disconnection; iii) depression and alcohol/substance use disorder; iv) depression and gender dysphoria; v) depression, stressful events, and other environmental factors.

EXPERT OPINION

In the novel depression subtypes discussed, individualized treatment approaches tailored to the individual's specific circumstances are necessary. While selective serotonin reuptake inhibitors (SSRIs) and serotonin and noradrenaline reuptake inhibitors (SNRIs) remain the cornerstone of treatment for many forms of depression, atypical antidepressants such as trazodone, and emerging therapies like ketamine, neuromodulation techniques, and personalized psychotherapy offer hope for those with complex or treatment-resistant presentations.

Trajectories of pharmacological therapies for treatment-resistant depression: a longitudinal study

BACKGROUND

Treatment-resistant depression (TRD) in major depressive disorder (MDD) is defined as the failure of two or more antidepressants. Few studies have characterized the natural history and treatment patterns of these patients. This study aims to identify the natural history of disease and treatment trajectories for patients with TRD.

METHODS

A retrospective longitudinal study used claims data linked to electronic health records (EHRs) from January 1, 2017, to October 31, 2021. Inclusion criteria were age ≥ 18 years, ≥ 1 MDD diagnosis, no antidepressant use at baseline, and an index date within 90 days of MDD diagnosis. Exclusions included psychiatric disorders other than MDD. TRD patients were defined as receiving third-line antidepressant treatment within two years of first-line initiation. Second- and third-line antidepressant treatment was defined as a switch to or addition of a different antidepressant with an adequate dose/duration or initiation of an augmentation treatment.

RESULTS

Out of 301,821 individuals with MDD using antidepressants or augmentation medications during the study, 2,409 incident TRD patients were selected out of 50,374 meeting the criteria. The median time to TRD (time from first to third line index date) was 11.5 months, and the TRD episode duration was 10.8 months. Initial treatment was predominantly antidepressant monotherapy, declining from 91.0% in the first line to 39.4% in the third line. Combination therapy including antidepressants and augmentation medications increased over lines, reaching 55.6% in the third line. During the TRD episode, SSRIs were the most prescribed antidepressants with the longest duration of use. Cognitive-behavioral therapy was used by 53.5% of TRD patients, while other nonpharmacological therapies were rarely used. Treatment trajectories varied by age, sex, and anxiety.

CONCLUSIONS

This study identified contemporary treatment patterns in TRD patients, with combination therapy and augmentation medications increasingly used, highlighting the need for precision treatment based on individual trajectories.

Perspectives in treatment-resistant depression: esketamine and electroconvulsive therapy

Modern electroconvulsive therapy (ECT) and the approval of nasal esketamine for clinical use have significantly improved the approach to treatment-resistant depression (TRD), which is defined as non-response to at least two different courses of antidepressants with verified adherence to treatment, adequate dosage, and duration of treatment. The goal of this literature review is to present the newest evidence regarding efficacy and safety. Furthermore, we aim to provide an overview of future perspectives in this field of research, for example, regarding structural and molecular effects. Both treatment methods will be critically evaluated for their individual advantages, disadvantages, and response rates. Firstly, we will discuss the well-established method of ECT and its different treatment modalities. Secondly, we will discuss the properties of ketamine, the discovery of its antidepressive effects and the route to clinical approval of the esketamine nasal spray. We will comment on research settings which have evaluated intravenous ketamine against ECT. The decision-making process between esketamine nasal spray or ECT should include the assessment of contraindications, age, severity of disease, presence of psychotic symptoms, patient preference and treatment accessibility. We conclude that both treatment options are highly effective in TRD. If both are indicated, pragmatically esketamine will be chosen before ECT; however, ECT studies in ketamine non-responders are missing.

Hypomanic symptoms in major depressive disorder: Prognostic impact and treatment issues

BACKGROUND

Mixed depression (MXD), defined as (hypo)manic symptoms occurring within major depressive episodes, is common in both bipolar and unipolar disorders, but its prognostic and treatment implications remain unclear. This study aimed to examine the relationship between hypomanic symptoms, treatment response and remission of suicidal thoughts.

METHODS

We analyzed 1243 adults with major depressive disorder (MDD), recruited for a naturalistic study on treatment-resistant depression. Data were gathered cross-sectionally and retrospectively through structured interviews and clinical rating scales including the Young Mania Rating Scale (YMRS) and Montgomery-Asberg Depression Rating Scale (MADRS); statistical analyses were performed using univariate and multivariate methods.

RESULTS

Hypomanic symptoms were present in 651 patients (45 %), while 307 patients (25 %) responded to treatment. Both treatment responders (p < 0.0001) and those who achieved remission from suicide ideation (p = 0.0085) showed lower hypomanic (YMRS) scores. Multivariate analysis showed that hypomanic symptoms were negatively linked to treatment response (O.R. 0.71-0.87), while bipolar spectrum markers such as age at illness onset (O.R. 1.00-1.03) and MDD recurrence (O.R. 0.47-0.89) predicted remission from suicidal thoughts. Medications commonly used to treat bipolar disorder showed some benefits, with dopamine/serotonin antagonists improving suicide ideation (p < 0.0001) and mood stabilizers being associated with reduced hypomanic symptoms (p = 0.0003).

LIMITATIONS

The study lacked prospective clinical assessments and treatment randomization.

CONCLUSION

Hypomanic symptoms are common in unipolar depression; their assessment is essential to identify challenging-to-treat cases and select the best pharmacological options.

Compassionate use of esketamine intranasal in patients with severe major depressive disorder resistant to the treatment

BACKGROUND

Treatment-resistant depression (TRD) is defined as the failure of at least two antidepressants in adequate doses and timing during a major depressive episode. Esketamine intranasal (ESK-IN) has been approved by the Food and Drug Administration and the European Medicines Agency for the treatment of TRD in combination with other antidepressants.

AIMS

To assess the effectiveness and tolerability of a sample of TRD patients who received treatment with ESK-IN as part of the compassionate use program.

METHODS

A retrospective, observational study was carried out on patients with a diagnosis of TRD enrolled in the early access program of ESK-IN in nine centers. Effectiveness was assessed with the Montgomery-Asberg depression rating scale (MADRS) at four time points: baseline, 28, 90, and 180 days of treatment.

RESULTS

The sample included 71 patients (70% women) with a mean baseline MADRS score of 38.27 ± 5.9 and total or partial work disability rates of 85%. ESK-IN treatment was associated with a statistically and clinically significant reduction in the severity of depressive symptoms at all time points assessed. The presence of side effects was common but the majority were mild in severity and resolved after the observation period. Those patients who received psychotherapy in combination with ESK-IN showed a significantly lower MADRS score at 90 and 180 days than those patients who did not undergo psychotherapy.

CONCLUSION

ESK-IN has proven to be effective and safe in a clinical sample of patients with severe TRD. To optimize clinical outcomes, the pharmacological treatment for TRD should always be integrated into a comprehensive therapeutic plan that encompasses strategies such as psychotherapy, social support, and family interventions.

Clinical associations with treatment resistance in depression: An electronic health record study

Treatment resistance is common in major depressive disorder (MDD), yet clinical risk factors are not well understood. Using a discovery-replication design, we conducted phenome-wide association studies (PheWASs) of MDD treatment resistance in two electronic health record (EHR)-linked biobanks. The PheWAS included participants with an MDD diagnosis in the EHR and at least one antidepressant (AD) prescription. Participant lifetime diagnoses were mapped to phecodes. PheWASs were conducted for three treatment resistance outcomes based on AD prescription data: number of unique ADs prescribed, ≥1 and ≥2 CE switches. Of the 180 phecodes significantly associated with these outcomes in the discovery cohort (n = 12,558), 71 replicated (n = 8,206). In addition to identifying known clinical factors for treatment resistance in MDD, the total unique AD prescriptions was associated with additional clinical variables including irritable bowel syndrome, gastroesophageal reflux disease, symptomatic menopause, and spondylosis. We calculated polygenic risk of specific-associated conditions and tested their association with AD outcomes revealing that genetic risk for many of these conditions is also associated with the total unique AD prescriptions. The number of unique ADs prescribed, which is easily assessed in EHRs, provides a more nuanced measure of treatment resistance, and may facilitate future research and clinical application in this area.

Anhedonia is associated with a specific depression profile and poor antidepressant response

BACKGROUND

Anhedonic features within major depressive disorder (MDD) have been associated with worse course and outcome and may predict nonresponse to treatment. However, a detailed clinical profile of anhedonia in MDD is still lacking.

MATERIALS AND METHODS

One thousand two hundred ninety-four patients with MDD were selected from the cross-sectional European multicenter Group for the Study of Resistant Depression study. Anhedonia was assessed through the Montgomery-Åsberg Depression Rating Scale anhedonia item "inability to feel." Clinical and demographic features were then analyzed.

RESULTS

The presence of anhedonia related to a distinct demographical (living alone) and clinical profile (thyroid diseases, diabetes, suicide risk, high number of previous depressive episodes, more severe MDD, and more frequent inpatient status). Furthermore, anhedonia was associated with nonresponse to treatment and treatment resistance, even after adjusting for confounding variables.

CONCLUSIONS

Our findings support the role of anhedonia as a modulating feature of MDD, being associated with a more severe depression profile. Moreover, anhedonic features are independent predictors of poor treatment response.

Does depression with current suicidal ideation lead to treatment-resistant depression? Two large naturalistic cohorts of outpatients with depression and current suicidal ideation

As treatment-resistant depression (TRD) is linked to suicidal behaviors and suicidal risk is a predictor of TRD, depression with current suicidal ideation (SI) may lead to TRD. Early identification of TRD risk factors in patients with depression and current SI is crucial. The aims of our study were: i) to identify risk factors for depression non-remission and TRD in patients with depression and current SI; ii) to assess if SI at baseline mediated the relationship between depression severity at baseline and depression remission at week 6. We analyzed data from two large, prospective, naturalistic French cohorts of adult outpatients with depression (DSM-IV criteria) followed for 6 weeks after starting or changing antidepressants (LUEUR and GENESE). Sociodemographic and clinical characteristics, along with early symptom improvement, were compared between patients with and without current SI using logistic regression models (univariate and multivariate). Patients with antidepressant change or initiation were analyzed separately. Those without depression remission at week 6 after an antidepressant change were considered TRD cases. In patients with antidepressant change, the major predictor of non-remission was poorer early improvement (at week 2) of anxiety. For patients with treatment initiation, SI at baseline mediated the relation between depression severity at baseline and depression remission. Depression severity at baseline alone did not explain depression remission. Clinicians should systematically target with specific pharmacological and non-pharmacological treatments anxiety and SI and assess their changes in the short term to increase the chance of depression remission in depressed patients with current SI.

Treatment-resistant depression: molecular mechanisms and management

Due to the heterogeneous nature of depression, the underlying etiological mechanisms greatly differ among individuals, and there are no known subtype-specific biomarkers to serve as precise targets for therapeutic efficacy. The extensive research efforts over the past decades have not yielded much success, and the currently used first-line conventional antidepressants are still ineffective for close to 66% of patients. Most clinicians use trial-and-error treatment approaches, which seem beneficial to only a fraction of patients, with some eventually developing treatment resistance. Here, we review evidence from both preclinical and clinical studies on the pathogenesis of depression and antidepressant treatment response. We also discuss the efficacy of the currently used pharmacological and non-pharmacological approaches, as well as the novel emerging therapies. The review reveals that the underlying mechanisms in the pathogenesis of depression and antidepressant response, are not specific, but rather involve an interplay between various neurotransmitter systems, inflammatory mediators, stress, HPA axis dysregulation, genetics, and other psycho-neurophysiological factors. None of the current depression hypotheses sufficiently accounts for the interactional mechanisms involved in both its etiology and treatment response, which could partly explain the limited success in discovering efficacious antidepressant treatment. Effective management of treatment-resistant depression (TRD) requires targeting several interactional mechanisms, using subtype-specific and/or personalized therapeutic modalities, which could, for example, include multi-target pharmacotherapies in augmentation with psychotherapy and/or other non-pharmacological approaches. Future research guided by interaction mechanisms hypotheses could provide more insights into potential etiologies of TRD, precision biomarker targets, and efficacious therapeutic modalities.

Basolateral amygdala parvalbumin and cholecystokinin-expressing GABAergic neurons modulate depressive and anxiety-like behaviors

The basolateral amygdala (BLA) is increasingly recognized as a key regulator of depression and anxiety-like behaviors. However, the specific contribution of individual BLA neurons to these behaviors remains poorly understood. Building on our previous study, which demonstrated increased activity in glutamatergic BLA neurons in response to aversive stimuli and that enhancing inhibition in the BLA can alleviate depressive-like behaviors, we investigated the role of individual BLA GABAergic neurons (BLAGABA) in depressive and anxiety-like phenotypes. To address this question, we employed a comprehensive array of techniques, including c-fos staining, fiber photometry recording, optogenetic and chemogenetic manipulation, and behavior analysis. Our findings indicate that BLAGABA neurons show decreased activity during tail suspension and after chronic social defeat stress (CSDS) during social interaction. High-frequency activation of BLAGABA neurons attenuated depressive and anxiety-like behaviors, while low-frequency activation had no effect. Fiber photometry recordings revealed increased activity in BLA GABAergic neurons expressing somatostatin (SST), parvalbumin (PV), and cholecystokinin (CCK) during footshock aversive stimuli. Moreover, we found increased activity in PV and SST neurons and decreased activity in CCK-GABA neurons in the BLA during tail suspension stress. However, after CSDS, BLAPV neurons displayed decreased activity, while SST and CCK neurons showed no changes during the social interaction test. Behavioral analysis demonstrated that chemogenetic inhibition of PV and CCK-GABA neurons induced depressive and anxiety-like behaviors. whereas SST neuron inhibition had no effect. Conversely, chemogenetic activation of BLAPV neurons alleviated depressive behaviors, and activation of BLACCK-GABA neurons alleviated at least partly both depressive and anxiety-like behaviors. This study provides compelling evidence that BLAPV neurons play a critical role in regulating depressive-like behaviors, and that BLACCK-GABA neurons are involved, at least in part, in modulating both depressive-like and anxiety-like behaviors in mice.

Neural signatures of emotional biases predict clinical outcomes in difficult-to-treat depression

Background

Neural predictors underlying variability in depression outcomes are poorly understood. Functional MRI measures of subgenual cortex connectivity, self-blaming and negative perceptual biases have shown prognostic potential in treatment-naïve, medication-free and fully remitting forms of major depressive disorder (MDD). However, their role in more chronic, difficult-to-treat forms of MDD is unknown.

Methods

Forty-five participants (n = 38 meeting minimum data quality thresholds) fulfilled criteria for difficult-to-treat MDD. Clinical outcome was determined by computing percentage change at follow-up from baseline (four months) on the self-reported Quick Inventory of Depressive Symptomatology (16-item). Baseline measures included self-blame-selective connectivity of the right superior anterior temporal lobe with an a priori Brodmann Area 25 region-of-interest, blood-oxygen-level-dependent a priori bilateral amygdala activation for subliminal sad vs happy faces, and resting-state connectivity of the subgenual cortex with an a priori defined ventrolateral prefrontal cortex/insula region-of-interest.

Findings

A linear regression model showed that baseline severity of depressive symptoms explained 3% of the variance in outcomes at follow-up (F[3,34] = .33, p = .81). In contrast, our three pre-registered neural measures combined, explained 32% of the variance in clinical outcomes (F[4,33] = 3.86, p = .01).

Conclusion

These findings corroborate the pathophysiological relevance of neural signatures of emotional biases and their potential as predictors of outcomes in difficult-to-treat depression.

Can the potential benefit of individualizing treatment be assessed using trial summary statistics alone?

Individualizing treatment assignment can improve outcomes for diseases with patient-to-patient variability in comparative treatment effects. When a clinical trial demonstrates that some patients improve on treatment while others do not, it is tempting to assume that treatment effect heterogeneity exists. However, if outcome variability is mainly driven by factors other than variability in the treatment effect, investigating the extent to which covariate data can predict differential treatment response is a potential waste of resources. Motivated by recent meta-analyses assessing the potential of individualizing treatment for major depressive disorder using only summary statistics, we provide a method that uses summary statistics widely available in published clinical trial results to bound the benefit of optimally assigning treatment to each patient. We also offer alternate bounds for settings in which trial results are stratified by another covariate. Our upper bounds can be especially informative when they are small, as there is then little benefit to collecting additional covariate data. We demonstrate our approach using summary statistics from a depression treatment trial. Our methods are implemented in the rct2otrbounds R package.

Major challenges in youth psychopathology: treatment-resistant depression. A narrative review

Major depressive disorder (MDD) represents a major health issue in adolescents and young adults, leading to high levels of disability and profoundly impacting overall functioning. The clinical presentation of MDD in this vulnerable age group may slightly differ from what can be observed in adult populations, and psychopharmacological strategies do not always lead to optimal response. Resistance to antidepressant treatment has a prevalence estimated around 40% in youths suffering from MDD and is associated with higher comorbidity rates and suicidality. Several factors, encompassing biological, environmental, and clinical features, may contribute to the emergence of treatment-resistant depression (TRD) in adolescents and young adults. Furthermore, TRD may underpin the presence of an unrecognized bipolar diathesis, increasing the overall complexity of the clinical picture and posing major differential diagnosis challenges in the clinical practice. After summarizing current evidence on epidemiological and clinical correlates of TRD in adolescents and young adults, the present review also provides an overview of possible treatment strategies, including novel fast-acting antidepressants. Despite these pharmacological agents are promising in this population, their usage is expected to rely on risk-benefit ratio and to be considered in the context of integrated models of care.

The clinical perspective on late-onset depression in European real-world treatment settings

The clinical phenotype of the so-called late-onset depression (LOD) affecting up to 30% of older adults and yielding heterogeneous manifestations concerning symptoms, severity and course has not been fully elucidated yet. This European, cross-sectional, non-interventional, naturalistic multicenter study systematically investigated socio-demographic and clinical correlates of early-onset depression (EOD) and LOD (age of onset ≥ 50 years) in 1410 adult in- and outpatients of both sexes receiving adequate psychopharmacotherapy. In a total of 1329 patients (94.3%) with known age of disease onset, LOD was identified in 23.2% and was associated with unemployment, an ongoing relationship, single major depressive episodes, lower current suicidal risk and higher occurrence of comorbid hypertension. In contrast, EOD was related to higher rates of comorbid migraine and additional psychotherapy. Although the applied study design does not allow to draw any causal conclusions, the present results reflect broad clinical settings and emphasize easily obtainable features which might be characteristic for EOD and LOD. A thoughtful consideration of age of onset might, hence, contribute to optimized diagnostic and therapeutic processes in terms of the globally intended precision medicine, ideally enabling early and adequate treatment allocations and implementation of respective prevention programs.

Facts and myths about use of esketamine for treatment-resistant depression: a narrative clinical review

Introduction and aims

Treatment-resistant depression (TRD) occurs when at least two different antidepressants, taken at the right dosage, for adequate period of time and with continuity, fail to give positive clinical effects. Esketamine, the S-enantiomer of ketamine, was recently approved for TRD treatment from U.S. Food and Drug Administration and European Medicine Agency. Despite proved clinical efficacy, many misconceptions by clinicians and patients accompany this medication. We aimed to review the most common "false myths" regarding TRD and esketemine, counterarguing with evidence-based facts.

Methods

The keywords "esketamine", "treatment resistance depression", "depression", "myth", "mythology", "pharmacological treatment", and "misunderstanding" were entered in the main databases and combined through Boolean operators.

Results

Misconceptions regarding the TRD prevalence, clinical features and predictors have been found. With respect of esketamine, criteria to start treatment, dissociative symptoms, potential addiction and aspects of administration and monitoring, were found to be affected by false beliefs by clinicians and patients.

Discussion and conclusion

TRD represents a challenging condition, requiring precise diagnosis in order to achieve patient's full recovery. Esketamine has been proved as an effective medication to treat TRD, although it requires precautions. Evidence can inform clinical practice, in order to offer this innovative treatment to all patients with TRD.

[Clinical management of treatment-resistant depression]

Treatment-resistant depression (TRD) is a complex disorder. Although no standardized definition has been established to date, there are promising and well-established treatment options for the condition. Looking at the current pharmacological and neuromodulatory strategies, there is an urgent need for fast-acting and well-tolerated treatment options. The search for new mechanisms of action goes beyond the monoamine hypothesis. For example, esketamine is already an established treatment method that is fast-acting and well tolerated, while psychedelics or esmethadone are currently still undergoing clinical trials. Compounds that can be used off-label, such as dextromethorphan or anti-inflammatory strategies are also presented. Pharmacological approaches that focus on the modulation of the glutamatergic system or belong to the class of psychedelics, appear to be of particular importance for current research and development. These particularly include substances that rapidly exert clinical effects and have a favorable side-effect profile.

A genetic risk score to predict treatment nonresponse in psychotic depression

Psychotic depression is a severe and difficult-to-treat subtype of major depressive disorder for which higher rates of treatment-resistant depression were found. Studies have been performed aiming to predict treatment-resistant depression or treatment nonresponse. However, most of these studies excluded patients with psychotic depression. We created a genetic risk score (GRS) based on a large treatment-resistant depression genome-wide association study. We tested whether this GRS was associated with nonresponse, nonremission and the number of prior adequate antidepressant trials in patients with a psychotic depression. Using data from a randomized clinical trial with patients with a psychotic depression (n = 122), we created GRS deciles and calculated positive prediction values (PPV), negative predictive values (NPV) and odds ratios (OR). Nonresponse and nonremission were assessed after 7 weeks of treatment with venlafaxine, imipramine or venlafaxine plus quetiapine. The GRS was negatively correlated with treatment response (r = -0.32, p = 0.0023, n = 88) and remission (r = -0.31, p = 0.0037, n = 88), but was not correlated with the number of prior adequate antidepressant trials. For patients with a GRS in the top 10%, we observed a PPV of 100%, a NPV of 73.7% and an OR of 52.4 (p = 0.00072, n = 88) for nonresponse. For nonremission, a PPV of 100%, a NPV of 51.9% and an OR of 21.3 (p = 0.036, n = 88) was observed for patients with a GRS in the top 10%. Overall, an increased risk for nonresponse and nonremission was seen in patients with GRSs in the top 40%. Our results suggest that a treatment-resistant depression GRS is predictive of treatment nonresponse and nonremission in psychotic depression.

The neurobiological mechanisms and therapeutic prospect of extracellular ATP in depression

BACKGROUND

Depression is a prevalent psychiatric disorder with high long-term morbidities, recurrences, and mortalities. Despite extensive research efforts spanning decades, the cellular and molecular mechanisms of depression remain largely unknown. What's more, about one third of patients do not have effective anti-depressant therapies, so there is an urgent need to uncover more mechanisms to guide the development of novel therapeutic strategies. Adenosine triphosphate (ATP) plays an important role in maintaining ion gradients essential for neuronal activities, as well as in the transport and release of neurotransmitters. Additionally, ATP could also participate in signaling pathways following the activation of postsynaptic receptors. By searching the website PubMed for articles about "ATP and depression" especially focusing on the role of extracellular ATP (eATP) in depression in the last 5 years, we found that numerous studies have implied that the insufficient ATP release from astrocytes could lead to depression and exogenous supply of eATP or endogenously stimulating the release of ATP from astrocytes could alleviate depression, highlighting the potential therapeutic role of eATP in alleviating depression.

AIM

Currently, there are few reviews discussing the relationship between eATP and depression. Therefore, the aim of our review is to conclude the role of eATP in depression, especially focusing on the evidence and mechanisms of eATP in alleviating depression.

CONCLUSION

We will provide insights into the prospects of leveraging eATP as a novel avenue for the treatment of depression.

Routine treatment pathways in a cohort of patients with major depression and suicidality in Italy: the ARIANNA observational study

BACKGROUND

Major Depressive Disorder (MDD) with suicidal ideation, intent, or behavior is a psychiatric emergency with controversial care management. Our study describes the comprehensive treatment pathways of this population in Italian routine clinical practice.

METHODS

ARIANNA [NCT04463108] is an observational prospective and retrospective cohort study involving both primary data collection and secondary data extract. A total of 137 adult MDD patients with suicidality were enrolled from 24 Italian care sites and followed for 90 days. Other than the description of treatment patterns, the impact of treatment on depressive symptoms and suicidality, the burden on the patient's and caregiver's quality of life, healthcare resource utilization and costs were described.

RESULTS

Of the 133 eligible patients, 68.4% were female, and the median age was 47. Approximately half of the study population had a current severe major depressive episode. Treatment strategies at the time of active suicidal ideation with intent definition/confirmation (t0) were heterogeneous, increasing in complexity during observation. According to the MADRS, patients with remission at t0+1 day were 2.6%, with the mean total score decreasing from 37.2 at t0 to 32.3.

LIMITATIONS

The study sites were not randomly selected.

CONCLUSIONS

To the best of our knowledge, this is the first cohort study that prospectively describes the characteristics of patients with MDD and suicide risk in Italy, and how they are treated in clinical practice. The study confirms this is a difficult-to-treat population. In addition, a lack of rapid, effective treatment for reducing depressive symptoms and suicidality is observed.

ICEBERG study: an indirect adjusted comparison estimating the long-term benefit of esketamine nasal spray when compared with routine treatment of treatment resistant depression in general psychiatry

Background

Treatment resistant depression (TRD) affects 10-30% of patients with major depressive disorder. In 4-week trials, esketamine nasal spray (NS) was efficacious vs. placebo when both were initiated in addition to a new selective serotonin or serotonin norepinephrine reuptake inhibitor. However, comparison with an extended range of real-world treatments (RWT) is lacking.

Methods

ICEBERG was an adjusted indirect treatment comparison using propensity score-based inverse probability weighting, performed on 6-month response and remission data from patients receiving esketamine NS plus oral antidepressant from the SUSTAIN-2 (NCT02497287; clinicaltrials.gov) study, compared with patients receiving other RWT from the European Observational TRD Cohort (EOTC; NCT03373253; clinicaltrials.gov) study. SUSTAIN-2 was a long-term open-label study of esketamine NS, while the EOTC was conducted at a time when esketamine NS was not available as RWT. Threshold and sensitivity analyses were conducted to assess how robust the primary analyses were.

Results

Patients receiving esketamine NS had a higher probability of 6-month response (49.7% [95% confidence interval (CI) 45.6-53.9]) and remission (33.6% [95% CI 29.7-37.6]) vs. patients receiving RWT (26.4% [95% CI 21.5-31.4] and 18.2% [95% CI 13.9-22.5], respectively), according to rescaled average treatment effect among treated estimates. Resulting adjusted odds ratios (OR) and relative risk (RR) favoured esketamine NS over RWT for 6-month response (OR 2.756 [95% CI 2.034-3.733], p < 0.0001; RR 1.882 [95% CI 1.534-2.310], p < 0.0001) and remission (OR 2.276 [95% CI 1.621-3.196], p < 0.0001; RR 1.847 [95% CI 1.418-2.406], p < 0.0001). Threshold analyses suggested that differences between the two studies were robust, and results were consistent across extensive sensitivity analyses.

Conclusion

ICEBERG supports that, at 6 months, esketamine NS has a substantial and significant benefit over RWT for patients with TRD. While results may be affected by unobserved confounding factors, threshold analyses suggested these were unlikely to impact the study conclusions.To view an animated summary of this publication, please click on the Supplementary video.

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.

Brain-Derived Neurotrophic Factor (BDNF) as a Predictor of Treatment Response in Major Depressive Disorder (MDD): A Systematic Review

Brain-derived neurotrophic factor (BDNF) has been studied as a biomarker of major depressive disorder (MDD). Besides diagnostic biomarkers, clinically useful biomarkers can inform response to treatment. We aimed to review all studies that sought to relate BDNF baseline levels, or BDNF polymorphisms, with response to treatment in MDD. In order to achieve this, we performed a systematic review of studies that explored the relation of BDNF with both pharmacological and non-pharmacological treatment. Finally, we reviewed the evidence that relates peripheral levels of BDNF and BDNF polymorphisms with the development and management of treatment-resistant depression.

Esketamine in treatment-resistant depression patients comorbid with substance-use disorder: A viewpoint on its safety and effectiveness in a subsample of patients from the REAL-ESK study

Esketamine, the S-enantiomer of ketamine, has recently emerged as a therapy for treatment-resistant depression (TRD), showing both rapid antidepressant action and good efficacy and high safety. It is also indicated for the acute short-term treatment of psychiatric emergency due to major depressive disorder (MDD) and for depressive symptoms in adults with MDD with acute suicidal thoughts/behavior. We here provide preliminary insights on esketamine nasal spray (ESK-NS) effectiveness and safety among patients with a substance use disorder (SUD) within the sample of patients with TRD collected for the observational, retrospective, multicentre REAL-ESK study. Twenty-six subjects were retrospectively selected according to the presence of a SUD in comorbidity. Subjects enrolled completed the three different follow-up phases (T0/baseline, T1/after one month, and T2/after three months) and there were no dropouts. A decrease in Montgomery-Asberg depression rating scale (MADRS) scores was recorded, thus highlighting the antidepressant efficacy of ESK-NS (MADRS decreased from T0 to T1, t = 6.533, df=23, p<0.001, and from T1 to T2, t = 2.029, df=20, p = 0.056). Considering tolerability and safety issues, one or more side effects were reported by 19/26 subjects (73%) after treatment administration. All reported side effects were time-dependent and did not cause significant sequelae; among them, dissociative symptoms (38%) and sedation (26%) were the most frequently reported. Finally, no cases of abuse or misuse of ESK-NS were reported. Despite study limitations related to the inherent nature of the study, a limited number of patients, and a short follow-up period, ESK-NS showed to be effective and safe in patients diagnosed with TRD comorbid with a SUD.

Body mass index and clinical outcomes in individuals with major depressive disorder: Findings from the GSRD European Multicenter Database

BACKGROUND

Individuals with major depressive disorder (MDD) are at higher risk for obesity. In turn, weight gain is a predisposing factor for depression. Although clinical data are sparse, suicide risk also appears to be elevated in obese patients. This study used data from the European Group for the Study of Resistant Depression (GSRD) to investigate clinical outcomes associated with body mass index (BMI) in MDD.

METHODS

Data were drawn from 892 participants with MDD over the age of 18 years (580 female, 50.5 ± 13.6 years). Response and resistance to antidepressant medication, depression rating scale scores, and further clinical and sociodemographic variables were compared using multiple logistic and linear regressions controlled for age, sex, and risk of weight gain due to psychopharmacotherapy.

RESULTS

Of the 892 participants, 323 were categorized as treatment-responsive and 569 as treatment-resistant. Within this cohort, 278 (31.1 %) were overweight (BMI = 25-29.9 kg/m2) and 151 (16.9 %) were obese (BMI > 30 kg/m2). Elevated BMI was significantly associated with higher suicidality, longer duration of psychiatric hospitalizations over their lifetimes, earlier age of onset of MDD, and comorbidities. There was a trend-wise association of BMI with treatment resistance.

LIMITATIONS

Data were analyzed in a retrospective, cross-sectional design. BMI was used as an exclusive measure of overweight and obesity.

CONCLUSIONS

Participants with comorbid MDD and overweight/obesity were at risk for worse clinical outcomes, suggesting that weight gain should be closely monitored in individuals with MDD in daily clinical practice. Further studies are needed to explore the neurobiological mechanisms linking elevated BMI to impaired brain health.

Depressive symptoms and neuroticism-related traits are the main factors associated with wellbeing independent of the history of lifetime depression in the UK Biobank

BACKGROUND

Wellbeing has a fundamental role in determining life expectancy and major depressive disorder (MDD) is one of the main modulating factors of wellbeing. This study evaluated the modulators of wellbeing in individuals with lifetime recurrent MDD (RMDD), single-episode MDD (SMDD) and no MDD in the UK Biobank.

METHODS

Scores of happiness, meaningful life and satisfaction about functioning were condensed in a functioning-wellbeing score (FWS). We evaluated depression and anxiety characteristics, neuroticism-related traits, physical diseases, lifestyle and polygenic risk scores (PRSs) of psychiatric disorders. Other than individual predictors, we estimated the cumulative contribution to FWS of each group of predictors. We tested the indirect role of neuroticism on FWS through the modulation of depression manifestations using a mediation analysis.

RESULTS

We identified 47 966, 21 117 and 207 423 individuals with lifetime RMDD, SMDD and no MDD, respectively. Depression symptoms and personality showed the largest impact on FWS (variance explained ~20%), particularly self-harm, worthlessness feelings during the worst depression, chronic depression, loneliness and neuroticism. Personality played a stronger role in SMDD. Anxiety characteristics showed a higher effect in SMDD and no MDD groups. Neuroticism played indirect effects through specific depressive symptoms that modulated FWS. Physical diseases and lifestyle explained only 4-5% of FWS variance. The PRS of MDD showed the largest effect on FWS compared to other PRSs.

CONCLUSIONS

This was the first study to comprehensively evaluate the predictors of wellbeing in relation to the history of MDD. The identified variables are important to identify individuals at risk and promote wellbeing.

Real-world characteristics of European patients receiving SNRIs as first-line treatment for major depressive disorder

BACKGROUND

Serotonin-norepinephrine reuptake inhibitors (SNRIs) are among the most frequently prescribed antidepressants (ADs) for major depressive disorder (MDD), with an increasing trend in the last decade. Given the relative dearth of information regarding rationales for their preferred use as first-line ADs in the broad clinical routine, the present study systematically investigated real-world characteristics of MDD patients prescribed either SNRIs or other AD substances across different countries and treatment settings.

METHODS

In the present secondary analyses based on a large European, multi-site, naturalistic and cross-sectional investigation with a retrospective assessment of treatment outcome, we firstly defined the proportion of MDD patients receiving SNRIs as first-line AD psychopharmacotherapy and secondly compared their sociodemographic and clinical characteristics to those patients prescribed alternative first-line ADs during their current major depressive episode (MDE).

RESULTS

Within the total sample of 1410 MDD patients, 336 (23.8 %) received first-line SNRIs. Compared to other ADs, SNRIs were significantly associated with inpatient care, suicidality and treatment resistance during the current MDE, and a longer lifetime duration of psychiatric hospitalizations. Moreover, greater severity of depressive symptoms at study entry, higher daily doses of the administered ADs, as well as more frequent prescriptions of psychopharmacotherapeutic add-on strategies in general and antipsychotic augmentation in particular, were significantly related to first-line SNRIs.

CONCLUSIONS

Considering the limitations of a cross-sectional and retrospective study design, our data point towards a preferred use of first-line SNRIs in a generally more severely ill MDD patients, although they did not lead to superior treatment outcomes compared to alternative ADs.

Effects of bilateral sequential theta-burst stimulation on functional connectivity in treatment-resistant depression: First results

BACKGROUND

Previous studies suggest that transcranial magnetic stimulation exerts antidepressant effects by altering functional connectivity (FC). However, knowledge about this mechanism is still limited. Here, we aimed to investigate the effect of bilateral sequential theta-burst stimulation (TBS) on FC in treatment-resistant depression (TRD) in a sham-controlled longitudinal study.

METHODS

TRD patients (n = 20) underwent a three-week treatment of intermittent TBS of the left and continuous TBS of the right dorsolateral prefrontal cortex (DLPFC). Upon this trial's premature termination, 15 patients had received active TBS and five patients sham stimulation. Resting-state functional magnetic resonance imaging was performed at baseline and after treatment. FC (left and right DLPFC) was estimated for each participant, followed by group statistics (t-tests). Furthermore, depression scores were analyzed (linear mixed models analysis) and tested for correlation with FC.

RESULTS

Both groups exhibited reductions of depression scores, however, there was no significant main effect of group, or group and time. Anticorrelations between DLPFC and the subgenual cingulate cortex (sgACC) were observed for baseline FC, corresponding to changes in depression severity. Treatment did not significantly change DLPFC-sgACC connectivity, but significantly reduced FC between the left stimulation target and bilateral anterior insula.

CONCLUSIONS

Our data is compatible with previous reports on the relevance of anticorrelation between DLPFC and sgACC for treatment success. Furthermore, FC changes between left DLPFC and bilateral anterior insula highlight the effect of TBS on the salience network.

LIMITATIONS

Due to the limited sample size, results should be interpreted with caution and are of exploratory nature.

The update of self-identity: Importance of assessing autobiographical memory in major depressive disorder

Major depressive disorder is a leading global cause of disability. There is a growing interest for memory in mood disorders since it might constitute an original tool for prevention, diagnosis, and treatment. MDD is associated with impaired autobiographical memory characterized by a tendency to overgeneral memory, rather than vivid episodic self-defining memory, which is mandatory for problem-solving and projection in the future. This memory bias is maintained by three mechanisms: ruminations, avoidance, and impaired executive control. If we adopt a broader and comprehensive perspective, we can hypothesize that all those alterations have the potential to impair self-identity updating. We posit that this update requires a double referencing process: (1) to internalized self-representation and (2) to an externalized framework dealing with the representation of the consequence of actions. Diagnostic and therapeutic implications are discussed in the light of this model and the importance of assessing autobiographical memory in MDD is highlighted. This article is categorized under: Psychology > Memory Psychology > Brain Function and Dysfunction Neuroscience > Clinical.

Effects of bilateral sequential theta-burst stimulation on 5-HT1A receptors in the dorsolateral prefrontal cortex in treatment-resistant depression: a proof-of-concept trial

Theta-burst stimulation (TBS) represents a brain stimulation technique effective for treatment-resistant depression (TRD) as underlined by meta-analyses. While the methodology undergoes constant refinement, bilateral stimulation of the dorsolateral prefrontal cortex (DLPFC) appears promising to restore left DLPFC hypoactivity and right hyperactivity found in depression. The post-synaptic inhibitory serotonin-1A (5-HT1A) receptor, also occurring in the DLPFC, might be involved in this mechanism of action. To test this hypothesis, we performed PET-imaging using the tracer [carbonyl-11C]WAY-100635 including arterial blood sampling before and after a three-week treatment with TBS in 11 TRD patients compared to sham stimulation (n = 8 and n = 3, respectively). Treatment groups were randomly assigned, and TBS protocol consisted of excitatory intermittent TBS to the left and inhibitory continuous TBS to the right DLPFC. A linear mixed model including group, hemisphere, time, and Hamilton Rating Scale for Depression (HAMD) score revealed a 3-way interaction effect of group, time, and HAMD on specific distribution volume (VS) of 5-HT1A receptor. While post-hoc comparisons showed no significant changes of 5-HT1A receptor VS in either group, higher 5-HT1A receptor VS after treatment correlated with greater difference in HAMD (r = -0.62). The results of this proof-of-concept trial hint towards potential effects of TBS on the distribution of the 5-HT1A receptor. Due to the small sample size, all results must, however, be regarded with caution.

Melancholic features and typical neurovegetative symptoms of major depressive disorder show specific polygenic patterns

BACKGROUND

Major depressive disorder (MDD) is a highly prevalent psychiatric condition characterised by a heterogeneous clinical presentation and an estimated twin-based heritability of ~40-50 %. Different clinical MDD subtypes might partly reflect distinctive underlying genetics. This study aims to investigate if polygenic risk scores (PRSs) for different psychiatric disorders, personality traits, and substance use-related traits may be associated with different clinical subtypes of MDD (i.e., MDD with melancholic or psychotic features), higher symptom severity, or different clusters of depressive symptoms (i.e., sadness symptoms, typical neurovegetative symptoms, detachment symptoms, and negative thoughts).

METHODS

The target sample included 1149 patients with MDD, recruited by the European Group for the Study of Resistant Depression. PRSs for 25 psychiatric disorders and traits were computed based on the most recent publicly available summary statistics of the largest genome-wide association studies. PRSs were then used as predictors in regression models, adjusting for age, sex, population stratification, and recruitment sites.

RESULTS

Patients with MDD having higher PRS for MDD and loneliness were more likely to exhibit melancholic features of MDD (p = 0.0009 and p = 0.005, respectively). Moreover, patients with higher PRS for alcohol intake and post-traumatic stress disorder were more likely to experience greater typical neurovegetative symptoms (p = 0.0012 and p = 0.0045, respectively).

LIMITATIONS

The proportion of phenotypic variance explained by the PRSs was limited.

CONCLUSIONS

This study suggests that melancholic features and typical neurovegetative symptoms of MDD may show distinctive underlying genetics. Our findings provide a new contribution to the understanding of the genetic heterogeneity of MDD.

Beneficial effects of Silexan on co-occurring depressive symptoms in patients with subthreshold anxiety and anxiety disorders: randomized, placebo-controlled trials revisited

Silexan is a proprietary active substance produced from Lavandula angustifolia, with proven anxiolytic efficacy in subthreshold and generalized anxiety disorder as well as in mixed anxiety and depressive disorder with beneficial impact on anxiety-related sleep disturbances. The pharmacological profile and clinical observations suggest that Silexan may also have an antidepressant effect. To investigate the effect of Silexan on co-occurring depressive symptoms, we present a meta-analysis of the five placebo-controlled clinical trials hitherto performed with Silexan in subthreshold anxiety (n = 3) and anxiety disorders (n = 2). Patients of all trials received Silexan 1 × 80 mg/day or placebo for 10 weeks according to random assignment. Assessment of the antidepressant effect was based on item 'depressed mood' from the Hamilton Anxiety Rating Scale (HAMA) administered in all trials and on the total scores of the Montgomery Åsberg Depression Rating Scale (MADRS) or the Hamilton Depression Rating Scale (HAMD) used in three trials. After 10-week treatment, patients receiving Silexan showed significantly more pronounced score reduction for HAMA item 'depressed mood' than those in the placebo group (p = 0.01). Significant superiority of Silexan over placebo could also be shown for mean MADRS or HAMD total score reduction (three studies; p < 0.01). Silexan-treated patients with more severe depressive symptoms at baseline showed more pronounced improvements than those with milder symptoms. Our meta-analysis clearly shows that Silexan has a beneficial effect on co-occurring depressive symptoms in patients with subthreshold anxiety and anxiety disorders and may, hence, lead to important therapeutic implications for depressive disorders.

Dynorphin promotes stress-induced depressive behaviors by inhibiting ventral pallidal neurons in rats

AIM

Endogenous dynorphin signaling via kappa opioid receptors (KORs) plays a key role in producing the depressive and aversive consequences of stress. We investigated the behavioral effects of the dynorphin/KOR system in the ventral pallidum (VP) and studied the underlying mechanisms.

METHODS

To investigate the effects of dynorphin on the VP, we conducted behavioral experiments after microinjection of drugs or shRNA and brain-slice electrophysiological recordings. Histological tracing and molecular biological experiments were used to identify the distribution of KORs and the possible sources of dynorphin projections to the VP.

RESULTS

An elevated dynorphin concentration and increased KOR activity were observed in the VP after acute stress. Infusion of dynorphin-A into the VP produced depressive-like phenotypes including anhedonia and despair and anxiety behaviors, but did not alter locomotor behavior. Mechanistically, dynorphin had an inhibitory effect on VP neurons-reducing their firing rate and inhibiting excitatory transmission-through direct activation of KORs and modulation of downstream G-protein-gated inwardly rectifying potassium (GIRK) channels and high-voltage gated calcium channels (VGCCs). Tracing revealed direct innervation of VP neurons by dynorphin-positive projections; potential sources of these dynorphinergic projections include the nucleus accumbens, amygdala, and hypothalamus. Blockade of dynorphin/KOR signaling in the VP by drugs or viral knock-down of KORs significantly reduced despair behavior in rats.

CONCLUSIONS

Endogenous dynorphinergic modulation of the VP plays a critical role in mediating depressive reactions to stress.

Stratification of individuals with lifetime depression and low wellbeing in the UK Biobank

BACKGROUND

Previous studies stratified patients with major depressive disorder (MDD) based on their clinical characteristics. This study used this approach in individuals with lifetime MDD who reported low wellbeing, a group of high clinical relevance.

METHODS

We selected participants in the UK Biobank (UKB) with lifetime MDD and a wellbeing score in the lowest 25 %. A wellbeing score was previously created considering happiness, belief that own life is meaningful, health satisfaction and functioning in relevant areas. In the selected group, we applied latent class analysis using mood-spectrum symptoms and personality traits as input variables, then we compared the clinical-demographic and genetic (polygenic risk scores, PRSs) characteristics of the identified classes.

RESULTS

A total of 13,896 individuals were included and a model with five classes showed the best performance. The most common class (31.25 %) was characterised by periods of irritable mood and trait irritability with high neuroticism. A rarer class (16.49 %) showed depressive-manic mood fluctuations and risk-taking personality, higher percentage of males, atypical depressive symptoms, lower socio-economic status, higher PRS for attention-deficit hyperactivity disorder and lower PRS for education. The second most common class (29.79 %) showed worry as main personality trait with low risk of manic/irritable manifestations. The remaining classes showed an anxious-irritable personality profile and a purely depressive profile (4.92 % and 17.55 %, respectively).

LIMITATIONS

Our results may reflect the characteristics of UKB participants.

CONCLUSIONS

Subthreshold manic/irritable mood fluctuations and personality traits irritability and neuroticism may distinguish the most common groups with poor wellbeing in lifetime MDD.

Health care utilisation in treatment-resistant depression: a Swedish population-based cohort study

OBJECTIVE

To investigate the health care utilisation (HCU) among patients with treatment-resistant depression (TRD) compared to patients with depression not meeting TRD criteria.

METHODS

Nationwide Swedish registers were used to identify patients 18-69 years old with incident depression and antidepressant treatment. Patients were followed prospectively and defined as having TRD at start of the third distinct consecutive treatment episode. Each of the 16,329 identified TRD patients were matched with five comparators with depression not meeting criteria for TRD. Main outcome measure was total number of inpatient days and outpatient visits, and secondary outcome was HCU in connection with a main diagnosis of depression or suicide attempt.

RESULTS

TRD patients had a significantly higher risk of all-cause inpatient care than comparators (first year adjusted risk ratio [aRR] 3.03 [95%CI 3.01-3.05], years 1-3 aRR 2.15 [2.13-2.16]). This was more pronounced when the main diagnosis was depression (first year aRR 4.41 [4.36-4.45]), and after suicide attempt (first year aRR 4.43 [4.26-4.60]). Outpatient visits were also markedly more frequent for patients with TRD (first year aRR 2.05 [2.03-2.07]). Higher HCU among TRD patients persisted throughout follow-up.

CONCLUSIONS

Patients with TRD may have a twofold to fourfold higher HCU than other patients with depression.KEYPOINTSThis register-based prospective study investigated health care utilisation (HCU) among patients with treatment-resistant depression (TRD) compared to other patients with depression.Patients with TRD had a two to fourfold higher HCU regarding all measured outcomes, including inpatient hospital days and outpatient visits.The elevated HCU persisted for more than three years, although decreasing gradually. This should correspond to increased costs and individual burden for patients with TRD.

The Impact of Theta-Burst Stimulation on Cortical GABA and Glutamate in Treatment-Resistant Depression: A Surface-Based MRSI Analysis Approach

Background: Theta burst stimulation (TBS) belongs to one of the biological antidepressant treatment options. When applied bilaterally, excitatory intermittent TBS (iTBS) is commonly targeted to the left and inhibitory continuous TBS (cTBS) to the right dorsolateral prefrontal cortex. TBS was shown to influence neurotransmitter systems, while iTBS is thought to interfere with glutamatergic circuits and cTBS to mediate GABAergic neurotransmission. Objectives: We aimed to expand insights into the therapeutic effects of TBS on the GABAergic and glutamatergic system utilizing 3D-multivoxel magnetic resonance spectroscopy imaging (MRSI) in combination with a novel surface-based MRSI analysis approach to investigate changes of cortical neurotransmitter levels in patients with treatment-resistant depression (TRD). Methods: Twelve TRD patients (five females, mean age ± SD = 35 ± 11 years) completed paired MRSI measurements, using a GABA-edited 3D-multivoxel MEGA-LASER sequence, before and after 3 weeks of bilateral TBS treatment. Changes in cortical distributions of GABA+/tNAA (GABA+macromolecules relative to total N-acetylaspartate) and Glx/tNAA (Glx = mixed signal of glutamate and glutamine), were investigated in a surface-based region-of-interest (ROI) analysis approach. Results: ANCOVAs revealed a significant increase in Glx/tNAA ratios in the left caudal middle frontal area (p corr. = 0.046, F = 13.292), an area targeted by iTBS treatment. Whereas, contralateral treatment with cTBS evoked no alterations in glutamate or GABA concentrations. Conclusion: This study demonstrates surface-based adaptions in the stimulation area to the glutamate metabolism after excitatory iTBS but not after cTBS, using a novel surface-based analysis of 3D-MRSI data. The reported impact of facilitatory iTBS on glutamatergic neurotransmission provides further insight into the neurobiological effects of TBS in TRD.

Staging of unipolar depression: systematic review and discussion of clinical implications

Staging has been increasingly used in unipolar depression since its introduction in the nineties. Several models are available, but their differential features and implications are not completely clear. We systematically reviewed: (a) staging models of longitudinal development of unipolar depression; (b) staging models of treatment-resistant unipolar depression; (c) their applications. MEDLINE, PsycINFO, EMBASE, and Web of Science were examined according to PRISMA guidelines from inception to December 2021. Search terms were: 'stage/staging', combined using the Boolean 'AND' operator with 'psychiatric disorder/mental disorder/depressive/mood disorder'. A total of 169 studies were identified for inclusion: 18 described staging models or applications, 151 described treatment-resistant staging models or applications. Staging models of longitudinal development were found to play a key role in formulating sequential treatment, with particular reference to the use of psychotherapy after pharmacotherapy. Staging methods based on treatment resistance played a crucial role in setting entry criteria for randomized clinical trials and neurobiological investigations. Staging is part of clinimetrics, the science of clinical measurements, and its role can be enhanced by its association with other clinimetric strategies, such as repeated assessments, organization of problematic areas, and evaluation of phenomena that may affect responsiveness. In research, it may allow to identify more homogeneous populations in terms of treatment history that may diminish the likelihood of spurious results in comparisons. In clinical practice, the use of staging in a clinimetric perspective allows clinicians to make full use of the information that is available for an individual patient at a specific time.

Key considerations for the use of ketamine and esketamine for the treatment of depression: focusing on administration, safety, and tolerability

INTRODUCTION

Racemic ketamine, a derivative of phencyclidine, has been used as a dissociative anesthetic since 1970. In 2000, the first randomized controlled trial showed a rapid relief of depressive symptoms. Since then, intravenous ketamine and intranasal S-ketamine have been validated for the treatment of depression and suicidal ideation following dose-response and double-blind placebo-controlled clinical trials. In clinical practice, after dose titration and with repeated treatments, patients may experience approximately 2-3 weeks of symptomatic relief from depression.

AREAS COVERED

Areas covered in this narrative review include mechanism of action, dosing, safety, and tolerability. Some attention is paid to the possibility of R-ketamine as a future antidepressant.

EXPERT OPINION

We recommend further investigation into treatment dosing and frequency strategies as well as approaches that prolong the therapeutic effects. The current fixed dosing of esketamine for obese individuals may be insufficient. Additional investigation into co-administration with somatic and neuromodulation treatments needs investigation. Finally, continuing to monitor research subjects and patients long-term for the emergence of adverse effects on cognition or other organ systems is critical.

Association of Treatment With Antipsychotics, Antidepressants, or Both With Movement Disorders and Seizures Among Children and Adolescents With Depression in Korea

IMPORTANCE

Little evidence exists on neurological adverse events (movement disorders and seizures) that occur during adjuvant use of antipsychotics with antidepressants, especially in children and adolescents.

OBJECTIVE

To assess the association between neurological adverse events (movement disorders, including parkinsonism, dystonia, extrapyramidal symptoms, chorea, and tic, and seizures) and the adjuvant use of antipsychotics in children and adolescents with depression.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective cohort study using the Health Insurance Review and Assessment claims database in Korea between 2008 and 2018. The study population was children and adolescents aged 2 to 18 years with depression who began treatment with antidepressants between January 1, 2010, and December 31, 2018. Data were analyzed between December 9, 2020, and December 10, 2021.

EXPOSURE

Time-varying exposure to antidepressants, antipsychotics, and concomitant use of antidepressants and antipsychotics. Concomitant use was further subdivided according to the antipsychotic treatment status (dose and agent).

MAIN OUTCOMES AND MEASURES

The extended Cox proportional hazards regression model, with adjustment for sex, age, health insurance type, psychiatric comorbidities, psychiatric hospitalization, and comedication with other psychotropic drugs, was used to estimate adjusted hazard ratios (aHRs) and 95% CIs for the associations of movement disorders and seizures with use of antidepressants and antipsychotics.

RESULTS

A total of 9890 patients were included in the study: 9541 (mean [SD] age, 14.8 [2.8] years; 4956 [51.9%] female) and 7731 (mean [SD] age, 14.9 [2.7] years; 4150 [53.7%] female) met the inclusion criteria for movement disorders and seizures, respectively. For movement disorders, associations were found between concomitant use (aHR, 3.68; 95% CI, 3.06-4.44) and antipsychotic-only use (aHR, 3.84; 95% CI, 3.03-4.87) compared with antidepressant-only use, but their CIs overlapped. The associations with seizure were similar (concomitant use: aHR, 2.06; 95% CI, 1.66-2.55; antipsychotic-only use: aHR, 2.05; 95% CI, 1.53-2.75). With concomitant use, the aHRs gradually increased with increasing doses of antipsychotics. Haloperidol had the highest aHR, 7.15 (95% CI, 3.89-10.00) for movement disorders. The highest aHR for seizure was observed with quetiapine (aHR, 2.36; 95% CI, 1.55-3.59), followed by aripiprazole (aHR, 2.05; 95% CI, 1.52-2.77).

CONCLUSIONS AND RELEVANCE

In this cohort study, adjunctive antipsychotics with antidepressants were associated with movement disorders and seizures compared with antidepressant monotherapy in children and adolescents with depression. These results suggest that careful consideration of the risk-benefit profile of the antipsychotic use as adjuvant therapy in this population is needed.

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.

Accelerated HF-rTMS Modifies SERT Availability in the Subgenual Anterior Cingulate Cortex: A Canine [11C]DASB Study on the Serotonergic System

Repetitive transcranial magnetic stimulation (rTMS) is thought to partly exert its antidepressant action through the serotonergic system. Accelerated rTMS may have the potential to result in similar but faster onset of clinical improvement compared to the classical daily rTMS protocols, but given that delayed clinical responses have been reported, the neurobiological effects of accelerated paradigms remain to be elucidated including on this neurotransmitter system. This sham-controlled study aimed to evaluate the effects of accelerated high frequency rTMS (aHF-rTMS) over the left frontal cortex on the serotonin transporter (SERT) in healthy beagle dogs. A total of twenty-two dogs were randomly divided into three unequal groups: five active stimulation sessions (five sessions in one day, n = 10), 20 active stimulation sessions (five sessions/day for four days, n = 8), and 20 sham stimulation sessions (five sessions/day for four days, n = 4). The SERT binding index (BI) was obtained at baseline, 24 h post stimulation protocol, one month, and three months post stimulation by a [11C]DASB PET scan. It was found that one day of active aHF-rTMS (five sessions) did not result in significant SERT BI changes at any time point. For the 20 sessions of active aHF-rTMS, one month after stimulation the SERT BI attenuated in the sgACC. No significant SERT BI changes were found after 20 sessions of sham aHF-rTMS. A total of four days of active aHF-rTMS modified sgACC SERT BI one month post-stimulation, explaining to some extent the delayed clinical effects of accelerated rTMS paradigms found in human psychopathologies.

Evidence on sociodemographic and clinical correlates of antidepressant combination or augmentation with second-generation antipsychotics in major depressive disorder

About two thirds of the patients with major depressive disorder (MDD) do not sufficiently respond to monotherapy with antidepressants (ADs) which makes them reliant on further treatment approaches. Hereby, combination of different ADs and augmentation with second-generation antipsychotics (SGAs) are widely used and recommended psychopharmacotherapeutic strategies. The present secondary analyses are based on an international, naturalistic, cross-sectional multicenter study conducted by the European Group for the Study of Resistant Depression. Comparing socio-demographic and clinical characteristics of 436 adult MDD patients receiving either SGAs (N = 191, 43.8%) or ADs (N = 245, 56.2%), that were additionally administered to their first-line AD psychopharmacotherapy, we aimed to identify possible trajectories of decision-making for clinicians regarding which treatment option to prefer in individual patients. Our most robust findings represent an association of SGA augmentation with the presence of psychotic symptoms, longer mean duration of lifetime psychiatric hospitalizations, employment of further augmentation strategies with mood-stabilizers and benzodiazepines, and a trend towards higher mean daily dosages of their first-line ADs and current suicidal risk. Treatment outcome was not significantly different between patients receiving either SGA augmentation or AD combination. Being aware of limitations inherent to the cross-sectional study design and the lack of randomization, more severe and rather chronic conditions in MDD seemed to encourage clinicians to choose SGA augmentation over AD combination. The fact that mood-stabilizers and/or benzodiazepines were more frequently co-administered with SGAs may represent a requirement of an overall refined psychopharmacotherapy including additional fast-acting agents with potent AD, tranquilizing and anti-suicidal effects in MDD patients experiencing challenging clinical manifestations. New glutamatergic substances seem to be promising in this regard.

Metabolizing status of CYP2C19 in response and side effects to medications for depression: Results from a naturalistic study

Major depressive disorder (MDD) is one of the leading causes of disability worldwide. Polymorphisms in cytochrome P450 genes (CYP450) were demonstrated to play a significant role in antidepressant response and side effects, but their effect in real-world clinical practice is poorly known. We determined the metabolic status of CYP2C19 based on the combination of *1, *2, *3 and *17 alleles extracted from genome-wide data in 1239 patients with MDD, pharmacologically treated in a naturalistic setting. Symptom improvement and side effects were assessed using the Montgomery and Åsberg Depression Rating Scale and the Udvalg for Kliniske Undersøgelse scale, respectively. We tested if symptom improvement, response and side effects were associated with CYP2C19 metabolic status adjusting for potential confounders. We considered patients treated with drugs for depression having CYP2C19 genotyping recommended by guidelines (T1 Drugs); secondarily, with all psychotropic drugs having CYP2C19 as relevant metabolic path (T2 Drugs). In the group treated with T1 drugs (n = 540), poor metabolizers (PMs) showed higher response and higher symptom improvement compared to normal metabolizers (p = 0.023 and p = 0.009, respectively), but also higher risk of autonomic and neurological side effects (p = 0.022 and p = 0.022 respectively). In patients treated with T2 drugs (n = 801), similar results were found. No associations between metabolizer status and other types of side effects were found (psychic and other side effects). Our study suggests potential advantages of CYP2C19 pharmacogenetic testing to guide treatment prescription, that may not be limited to the drugs currently recommended by guidelines.