A Delphi-method-based consensus guideline for definition of treatment-resistant depression for clinical trials

Middle frontal gyrus volume mediates the relationship between interleukin-1β and antidepressant response in major depressive disorder

Inflammation is a leading biological risk factor contributing to unfavorable outcomes of major depressive disorder (MDD). Both inflammation and depression are associated with similar alterations in brain structure, indicating that brain structural alterations could serve as a mediating factor in the adverse influence of inflammation on clinical outcomes in MDD. Nonetheless, longitudinal research has yet to confirm this hypothesis. Therefore, this study aimed at elucidating the relationships between peripheral inflammatory cytokines, gray matter volume (GMV) alterations, and antidepressant response in MDD. We studied 104 MDD patients treated with selective serotonin reuptake inhibitors and 85 healthy controls (HCs). Antidepressant response was assessed after 8-week antidepressant treatment by changes in 17-item Hamilton Depression Rating Scale (HAMD-17) scores. The GMV alterations were investigated using a voxel-based morphometry analysis. Inflammatory cytokines were measured using flow cytometry. Partial correlations were used to explore the relationships between inflammatory cytokines, GMV alterations, and antidepressant response. Compared to HCs, MDD patients showed reduced GMVs primarily in the frontal-limbic area, right insula, and right superior temporal gyrus. Furthermore, the alterations in GMVs, particularly in the right middle frontal gyrus and the left anterior cingulate gyrus, were associated with ΔHAMD-17 and inflammatory cytokines. Additionally, GMV alterations in the right middle frontal gyrus mediated the negative relationship between interleukin -1β and ΔHAMD-17. This study contributes to understanding the effect of inflammation on the brain and their relationships with antidepressant response, offering a potential explanation for the connection between inflammatory status and treatment efficacy.

Investigating novel pharmacological strategies for treatment-resistant depression: focus on new mechanisms and approaches

INTRODUCTION

A substantial number of patients exhibit treatment-resistant depression (TRD), posing significant challenges to clinicians. The discovery of novel molecules or mechanisms that may underlie TRD pathogenesis and antidepressant actions is highly needed.

AREAS COVERED

Using the PubMed database, the authors searched for emerging evidence of novel approaches for TRD based on experimental and human studies. Herein, the authors discuss the mechanisms underlying glutamatergic antagonists, modulators of the opioid system, and tryptamine-derivate psychedelics as well as the emerging platforms to investigate novel pharmacological targets for TRD. A search for clinical trials investigating novel agents and interventions for TRD was also conducted.

EXPERT OPINION

The understanding of the multiple pathophysiological mechanisms involved in TRD may add further value to the effective treatment, contributing to a more personalized approach. Esketamine was approved for the treatment of TRD and novel drugs with rapid antidepressant actions such as psilocybin and buprenorphine have also been investigated as potential therapeutic strategies. Over the past decades, technological advances such as omics approaches have broadened our knowledge regarding molecular and genetic underpinnings of complex conditions like TRD. Omics approaches could open new avenues for investigating glial-mediated mechanisms, including their crosstalk with neurons, as therapeutic targets in TRD.

Teratogenic Risk Impact and Mitigation (TRIM): Study Protocol for the Development of a Decision Support Tool to Prioritize Medications for Risk Mitigation

INTRODUCTION

Preventing prenatal exposure to teratogenic medications is an important goal of regulatory risk mitigation efforts. In the USA, as of March 2024, 11 teratogenic medications have a required Risk Evaluation and Mitigation Strategy (REMS) program. It is unclear whether these programs target those medications with the most significant impact on public health and adverse pregnancy outcomes.

OBJECTIVES

This study aims to develop an innovative decision support tool that uses explicit, quantifiable criteria to facilitate prioritization of teratogenic medications for risk mitigation strategies.

METHODS

The Teratogenic Risk Impact and Mitigation (TRIM) decision support tool will be developed by a national panel via a modified Delphi approach to define measurable criteria, and a multi-criteria decision analysis to estimate criteria weights within a discrete choice experiment. The TRIM scores will then be calculated for 12 teratogenic drugs with active or eliminated REMS programs and for 12 teratogenic drugs without REMS. These drugs will be identified based on highest prenatal exposure prevalence in claims data of privately and publicly insured individuals. Data for the TRIM criteria levels for these 24 drugs will be identified from evidence searches and ad hoc analyses of the same claims data.

CONCLUSIONS

Teratogenic Risk Impact and Mitigation is intended to inform regulatory decision making about the need for risk mitigation programs for teratogenic medications by providing explicit, quantifiable, evidence-based criteria. The TRIM scores of 24 teratogenic drugs may provide benchmarks for considering REMS for marketed and new teratogenic medications.

Abnormal choroid plexus, hippocampus, and lateral ventricles volumes as markers of treatment-resistant major depressive disorder

AIM

One-third of patients with major depressive disorder (MDD) do not achieve full remission and have high relapse rates even after treatment, leading to increased medical costs and reduced quality of life and health status. The possible specificity of treatment-resistant depression (TRD) neurobiology is still under investigation, with risk factors such as higher inflammatory markers being identified. Given recent findings on the role of choroid plexus (ChP) in neuroinflammation and hippocampus in treatment response, the aim of the present study was to evaluate inflammatory- and trophic-related differences in these regions along with ventricular volumes among patients with treatment-sensitive depression (TSD), TRD, and healthy controls (HCs).

METHODS

ChP, hippocampal, and ventricular volumes were assessed in 197 patients with MDD and 58 age- and sex-matched HCs. Volumes were estimated using FreeSurfer 7.2. Treatment resistance status was defined as failure to respond to at least two separate antidepressant treatments. Region of interest volumes were then compared among groups.

RESULTS

We found higher ChP volumes in patients with TRD compared with patients with TSD and HCs. Our results also showed lower hippocampal volumes and higher lateral ventricular volumes in TRD compared with both patients without TRD and HCs.

CONCLUSIONS

These findings corroborate the link between TRD and neuroinflammation, as ChP volume could be considered a putative marker of central immune activity. The lack of significant differences in all of the region of interest volumes between patients with TSD and HCs may highlight the specificity of these features to TRD, possibly providing new insights into the specific neurobiological underpinnings of this condition.

Ketamine and Esketamine in Clinical Trials: FDA-Approved and Emerging Indications, Trial Trends With Putative Mechanistic Explanations

Ketamine has a long and very eventful pharmacological history. Its enantiomer, esketamine ((S)-ketamine), was approved by the US Food and Drug Administration (FDA) and EMA for patients with treatment-resistant depression (TRD) in 2019. The number of approved indications for ketamine and esketamine continues to increase, as well as the number of clinical trials. This analysis provides a quantitative overview of the use of ketamine and its enantiomers in clinical trials during 2014-2024. A total of 363 trials were manually assessed from clinicaltrial.gov with the search term "Ketamine." The highest number of trials were found for the FDA-approved indications: anesthesia (~22%) and pain management (~28%) for ketamine and TRD for esketamine (~29%). Clinical trials on TRD for both ketamine and esketamine also comprised a large proportion of these trials, and interestingly, have reached phase III and phase IV status. Combinatorial treatment of psychiatric disorders and non-psychiatric conditions with pharmacological and non-pharmacological combinations (electroconvulsive therapy, psychotherapeutic techniques, virtual reality, and transcranial magnetic stimulation) is prevalent. Sub-anesthetic doses of ketamine may represent novel therapeutic avenues in neuropsychiatric conditions, that is, major depression, schizophrenia, and bipolar disorder, where glutamate excitotoxicity and oxidative stress are likely to be involved. The study suggests that the number of ketamine studies will continue to grow and possible ketamine variants can be approved for treatment of additional indications.

Is there a risk of esketamine misuse in clinical practice?

In 2019, intranasal esketamine gained approval as a promising therapy for those individuals grappling with treatment-resistant depression. Both clinical trials and real-world studies have underscored its efficacy in alleviating and remitting depressive symptoms, with sustained benefits observed for nearly 4.5 years. As the S-enantiomer of ketamine, esketamine's dosing guidelines and strict medical supervision stem from prior research on ketamine's use in depression and history as a recreational drug. Despite initial concerns, long-term clinical studies have not documented instances of abuse, misuse, addiction or withdrawal, and the same was found in case reports or subsamples of high-risk populations with comorbidities such as substance use disorder or alcohol use disorder. Esketamine has proven to be safe and well tolerated without fostering new-onset substance use in vulnerable groups. Real-world studies reinforced these observations, reporting no adverse events (AEs) related to pharmacological interactions of esketamine with any other substance, and no new-onset drug or alcohol misuse, craving, misuse or diversion of use. Reports of esketamine craving remain rare, with only one case report documented in 2022. Most drug-related AEs reported in pharmacovigilance databases are those identified in the product's technical data sheet and with known reported frequency. More importantly, no register of illicit acquisition of esketamine or its tampering for obtaining ketamine or other altered products was found in our search. Overall, our review confirms esketamine's safety across diverse patient populations, reassuring its responsible use and the scarcity of reports of abuse or misuse since its introduction to the market.

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.

Efficacy and safety of gut microbiome-targeted treatment in patients with depression: a systematic review and meta-analysis

BACKGROUND

The study aimed to comprehensively analyze and establish a framework for evaluating the efficacy of microbiome-targeted treatment (MTT) for depression.

METHODS

We searched PubMed, Embase, Cochrane Library, Web of Science, and the Chinese National Knowledge Infrastructure database for randomized controlled trials (RCTs) on MTT in treating depression until October 19, 2023. A meta-analysis was conducted to evaluate the efficacy and safety of MTT. Comprehensive subgroup analyses were undertaken to explore factors influencing MTT's efficacy in treating depression. This study was registered with PROSPERO (CRD42023483649).

RESULTS

The study selection process identified 51,570 studies, of which 34 met the inclusion criteria. The overall pooled estimates showed that MTT significantly improved depression symptoms (SMD -0.26, 95% CI [-0.32, -0.19], I2 = 54%) with acceptable safety. Subgroup analyses by geography showed that effectiveness was demonstrated in Asia (SMD -0.46, 95% CI [-0.56, -0.36], I2 = 36%), while no evidence of effectiveness was found in Europe (SMD -0.07, 95% CI [-0.19, 0.05], I2 = 55%), America (SMD -0.33, 95% CI [-0.67, 0.02], I2 = 60%), and Oceania (SMD 0.00, 95% CI [-0.18, 0.18], I2 = 0%). Besides, the efficacy was shown in depressed patients without comorbidities (SMD -0.31, 95% CI [-0.40, -0.22], I2 = 0%), whereas effectiveness was poor in those with digestive disorders, such as irritable bowel syndrome (SMD -0.37, 95% CI [-0.89, 0.16], I2 = 74%), chronic diarrhea (SMD -0.34, 95% CI [-0.73, 0.05]), and chronic constipation (SMD -0.23, 95% CI [-0.57, 0.11], I2 = 0%). In perinatal depressed patients, MTT was not effective (SMD 0.16, 95% CI [0.01, 0.31], I2 = 0%). It was found that < 8 weeks (SMD -0.33, 95% CI [-0.45, -0.22], I2 = 0%) and 8-12 weeks (SMD -0.34, 95% CI [-0.44, -0.23], I2 = 57%) MTT were effective, while > 12 weeks (SMD 0.02, 95% CI [-0.12, 0.17], I2 = 68%) MTT was ineffective.

CONCLUSIONS

Despite the overall effectiveness of MTT in treating depression and its acceptable safety profile, caution is warranted in drawing this conclusion due to limitations posed by the small sample size of included studies and heterogeneity. The efficacy of MTT for depression exhibits variation influenced by geography, patient comorbidities, and duration of administration.

Treatment-resistant depression: role of genetic factors in the perspective of clinical stratification and treatment personalisation

Treatment-resistant depression (TRD) is associated with chronic depression, suicidal behaviours, and reduced quality of life. TRD has a demonstrated genetic component, estimated around 8% based on common genetic variation in unrelated individuals. However, only six genome-wide association studies of TRD were published, and no replicated signals at locus or gene level have been identified; furthermore, apparently opposite results were reported in terms of genetic overlap between TRD and other traits. Other than limited power, an important issue of previous studies was the scarce consideration of TRD heterogeneity, as TRD likely comprises different groups and talking about TRDs could be more appropriate. This review points out important issues in the definition of TRD and differences across samples included in previous studies, which can be partly responsible for the inconsistency across results. Different definitions of TRD should not be expected to have similar genetic profiles, and the whole TRD group can partitioned into subgroups, based on clinical and biological features, to increase reproducibility, as exemplified by recent findings. This can be a key factor to develop/repurpose targeted treatments, or simply to aid a more personalised prescription of available medications compared to current clinical practice, that is largely concentrated on the prescription of a limited number of antidepressants compared to those available.

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.

Cause-specific mortality in treatment-resistant major depression: Population-based cohort study

BACKGROUND

Limited evidence-base on long-term prognosis of treatment-resistant major depression (TRD) is a barrier to clinical decision-making. Therefore, the purpose of this study was to establish cause-specific mortality in TRD compared to non-TRD major depression.

METHOD

We identified all individuals with a diagnosis of major depression (MDD) who were treated with an antidepressant aged 15 to 65 years during 2004-2016 in Finland. Persons with over two treatment trials were defined to have TRD. Data were analysed with Cox proportional hazard models.

RESULTS

176,942 individuals with MDD (63 % women, median age at index diagnosis 40 years), of whom 11 % (n = 19,305) fulfilled the TRD criteria, were followed-up for 1,525,646 person-years (median 8.9 years). There were 959 deaths (6.1 deaths/1000 person-years) in TRD and 7662 deaths (5.6/1000 person-years) in non-TRD. All-cause mortality was 17 % higher (adjusted hazard ratio (aHR), 1.17; 95 % confidence interval (CI), 1.09-1.25) in TRD compared to non-TRD, when sex and age at index antidepressant prescription were controlled for. In TRD, increased mortality was observed for suicides (aHR, 1.90; 95%CI, 1.64-2.20) and for accidental poisonings (aHR, 1.81; 95%CI, 1.48-2.22), but not for natural causes (aHR, 0.98; 95%CI, 0.90-1.07). A higher proportion of accidental drug overdoses was observed in TRD than in non-TRD (62 % vs 42 %, respectively).

LIMITATIONS

Definition of TRD lacks consensus. We used routine data to define TRD.

CONCLUSIONS

The markedly increased mortality due to suicides and accidental overdoses suggests that persons with TRD may experience higher intensity symptoms and more severe suicidal ideation than persons with non-TRD major depression.

Akrivia Health Database-deep patient characterisation using a secondary mental healthcare dataset in England and Wales: cohort profile

PURPOSE

The Akrivia Health cohort was created to extract data from electronic health records in secondary mental health and dementia care services in England and Wales. The data are anonymised, structured and harmonised from the source electronic health records across a range of information technology systems, enabling for unified, privacy-preserving access for research purposes.

PARTICIPANTS

The cohort contains data from electronic health records for over 4.6 million patients in England and Wales, as of January 2024. The data are refreshed with regularity, and the dataset expands whenever a new healthcare provider joins the Akrivia network. 13% of the database are patients under 18 years old (n=590 160), 56% are adults 18-65 years old (n=2 631 690) and 31% are older people (n=1 422 609). About 11.5% are deceased (n=538 371).

FINDINGS TO DATE

Structured data include patient demographics and service pathways. Akrivia Health also uses a bespoke natural language processing model to further extract the research-relevant information from free-text progress notes, including diagnoses, medications and clinical symptoms. This allows for an in-depth longitudinal description of patient journeys.

FUTURE PLANS

The anonymised data can be accessed in collaboration with Akrivia Health, following the National Health Service guidelines and without requiring a separate ethics application. There is no planned end date for data collection.

Flavonoids against depression: a comprehensive review of literature

Background

Depression is a state of low mood and aversion to activity, which affects a person's thoughts, behavior, motivation, feelings, and sense of wellbeing. Pharmacologic therapies are still the best effective treatment of depression. Still, most antidepressant drugs have low efficacy and delayed onset of therapeutic action, have different side effects, and even exacerbate depression. Such conditions make it possible to look for alternatives. Consequently, we decided to summarize the impact of flavonoids on depression in this review.

Methods

We searched scientific databases such as SCOPUS, PubMed, and Google Scholar to find relevant studies until July 2022.

Results

A wide variety of natural components have been shown to alleviate depression, one of which is flavonoids. Due to the growing tendency to use natural antidepressant drugs, scientific studies are increasingly being conducted on flavonoids. This study aims to review the latest scientific researches that indicate the antidepressant potential of flavonoids. Various mechanisms include neurotransmitter system modulation and dopaminergic, noradrenergic, and serotonergic pathways regulation in the central nervous system. Different compounds of flavonoids have antidepressant properties in vivo or in vitro experiments or clinical trials and can be used as alternative and complementary treatments for depression. In general, it was observed that there were no severe side effects.

Conclusion

Our study proves the antidepressant potential of flavonoids, and considering the limited side effects, they can be used as complementary medicine for depressed patients.

Developing guidelines for nursing management of epilepsy in Ghanaian schools

BACKGROUND

The absence of guidelines for the nursing management of individuals living with epilepsy, who are students in Ghana, has resulted in the high dropout rates of such students. It is our hope, that in the near future, these individuals living with epilepsy will receive the needed attention, experience less stigmatization and discrimination. This, we expect, will result in better retention of such students in schools, improved academic performance and successful graduation. To achieve this, there is the need to develop appropriate guidelines and implement same for their benefit. In line with this, the study aims to develop guidelines for nurses to manage individuals living with epilepsy in Ghanaian schools.

METHODOLOGY

Qualitative approach will be adopted to conduct this study in two phases. In the first phase, a case study design will be deployed in the Twifo Atti-Morkwa District of the Central Region of Ghana. The case is the nursing management of individuals living with epilepsy within the school context, and the sources of information will be the general nurses, psychiatric, or community psychiatric nurses working at the schools. Within the context of the case, parents or guardians of individuals living with epilepsy in the schools as well as their teachers will be included in the study. Data will be collected through individual interviews for nurses and parents while focus group discussions will be used for the teachers. Thematic analysis will be used to analyze the data. In the second phase, guidelines will be developed using the modified e-Delphi Technique. The study will be piloted in the Komenda-Edina-Eguafo-Abrem Municipality of the Central Region of Ghana. Ethics approval for this study has been obtained from the Ethical Review Committee of the University of Pretoria in South Africa. Additionally, Administrative approvals have been obtained from the Ghana Education Service.

DISCUSSION

The guidelines developed will form the basis for nursing management of individuals living with epilepsy in Ghanaian schools. This will help to improve educational outcomes for the individuals living with epilepsy.

Knowledge, attitudes, and practices among medical students toward depression management: a cross-sectional study in China

Background

The prevalence of depression among university and college students in China is nearly one-quarter. This study aimed to investigate the knowledge, attitudes and practices (KAP) among medical students toward depression management. Depression, a significant public health issue, has a substantial impact on students, with a reported prevalence of 23.8% among university and college students in China.

Methods

This web-based cross-sectional study was conducted between January 2023 and October 2023 at three medical universities in China. A self-administered questionnaire collected demographic information and assessed medical students' KAP on depression management.

Results

A total of 632 participants were enrolled in this study from three medical universities. Among them, 383 (60.60%) were female, and the participants were aged 20.17 years on average (SD ± 1.80). Most of their family members (521, 82.44%) were not in the medical profession. Using a validated 15-point knowledge scale, a 50-point attitude scale, and a 30-point practice scale, which covered areas such as symptom recognition, treatment approaches, and stigma related to depression, the mean knowledge, attitudes and practices scores were 10.55 ± 3.36 (possible range: 0-15), 41.72 ± 4.45 (possible range: 10-50) and 19.79 ± 5.44 (possible range: 6-30), respectively. Males had lower knowledge (p = 0.003). Only children had higher practice (p = 0.034). Urban residents had higher attitudes (p = 0.046). Higher income linked to better practice (p = 0.047). Freshmen scored higher across all KAP (p < 0.05). Medical family background linked to better knowledge (p = 0.005). The attitude scores were correlated with the practice scores (r = 0.403, p = 0.004). The structural equation model demonstrated that knowledge had direct effects on attitude and practice, as indicated by a path coefficient of 0.725 (p < 0.001) and 0.370 (p = 0.001), respectively. Furthermore, attitude had direct effects on practices, with a path coefficient of 0.509 (p < 0.001).

Conclusion

The study revealed that medical students possessed sufficient knowledge and demonstrated active attitudes but exhibited limited practical skills in managing depression. In investigating the KAP of medical students, it is essential to integrate specific practical applications, such as role-playing scenarios and case studies, into the curriculum. These methods will emphasize the importance of knowledge, foster positive attitudes, and promote peer collaboration to enhance practical skills in depression management.

Validation of the imperial psychedelic predictor scale

BACKGROUND

Access to psychedelic drugs is liberalizing, yet responses are highly unpredictable. It is therefore imperative that we improve our ability to predict the nature of the acute psychedelic experience to improve safety and optimize potential therapeutic outcomes. This study sought to validate the 'Imperial Psychedelic Predictor Scale' (IPPS), a short, widely applicable, prospective measure intended to be predictive of salient dimensions of the psychedelic experience.

METHODS

Using four independent datasets in which the IPPS was completed prospectively - two online surveys of 'naturalistic' use (N = 741, N = 836) and two controlled administration datasets (N = 30, N = 28) - we conducted factor analysis, regression, and correlation analyses to assess the construct, predictive, and convergent validity of the IPPS.

RESULTS

Our approach produced a 9-item scale with good internal consistency (Cronbach's α = 0.8) containing three factors: set, rapport, and intention. The IPPS was significantly predictive of 'mystical', 'challenging', and 'emotional breakthrough' experiences. In a controlled administration dataset (N = 28), multiple regression found set and rapport explaining 40% of variance in mystical experience, and simple regression found set explained 16% of variance in challenging experience. In another (N = 30), rapport was related to emotional breakthrough explaining 9% of variance.

CONCLUSIONS

Together, these data suggest that the IPPS is predictive of relevant acute features of the psychedelic experience in a broad range of contexts. We hope that this brief 9-item scale will be widely adopted for improved knowledge of psychedelic preparedness in controlled settings and beyond.

The Effects of Variation in the GABAA Receptor Gene on Anxious Depression are Mediated by the Functional Connectivity Between the Amygdala and Middle Frontal Gyrus

Background

γ-aminobutyric acid (GABA) and its main receptor, the GABAA receptor, are implicated in major depressive disorder (MDD). Anxious depression (AD) is deemed to be a primary subtype of MDD. The amygdala and the dorsolateral prefrontal cortex (DLPFC) are key brain regions involved in emotional regulation. These regions contain the most GABAA receptors. Although the GABAergic deficit hypothesis of MDD is generally accepted, few studies have demonstrated how GABAA receptor gene polymorphisms affect the functions of specific brain regions, in particular, the amygdala and the DLPFC.

Methods

The sample comprised 83 patients with AD, 70 patients with non-anxious depression (NAD), and 62 healthy controls (HC). All participants underwent genotyping for polymorphisms of GABAA receptor subunit genes, followed by a resting-state fMRI scan. The HAMD-17 was used to evaluate the severity of MDD. ANOVA was performed to obtain the difference in the imaging data, GABAA receptor multi-locus genetic profile scores (MGPS), and HAMD-17 scores among three groups, then the significant differences between AD and NAD groups were identified. Mediating effect analysis was used to explore the role of functional connectivity (FC) between the amygdala and DLPFC in the association between the GABAA receptor gene MGPS and AD clinical features.

Results

Compared with the NAD group, the AD group had a higher GABAA receptor MGPS. AD patients exhibited a negative correlation between the MGPS and FC of the right centromedial (CM) subregion, and the right middle frontal gyrus (MFG). A negative correlation was also observed between the MGPS and anxiety/somatic symptoms. More importantly, the right CM and right MFG connectivity mediated the association between the GABAA receptor MGPS and anxiety/somatic symptoms in patients with AD.

Conclusion

The decreased FC between the right MFG and right CM subregion mediates the association between GABAA receptor MGPS and AD.

Identification of Specific Plasma miRNAs as Potential Biomarkers for Major Depressive Disorder

BACKROUND

Depression is a significant concern in clinical and preclinical psychoneurobiological sciences due to its high prevalence and its individual and collective consequences. Identifying efficient biomarkers for accurate diagnosis is crucial, with ideal biomarkers having detectable serum levels and conformational and thermal stability. This study aims to identify stable plasma biomarkers for the diagnosis and prognosis of major depressive disorder, as the pathogenesis of the disorder remains incompletely understood, affecting diagnosis accuracy.

METHODS

Thus, this study included ten MDD patients and eight healthy controls. The present work analyzed miRNAs in patients with major depressive disorder compared to healthy controls.

RESULTS

Eleven specific miRNAs, particularly hsa-miR-874-3p; hsa-let-7d-5p; and hsa-miR-93-3p showed upregulation-type plasma variations in the group of patients with major depressive disorder. miRNA functionality is linked to depressive pathophysiology.

CONCLUSIONS

This study identifies a "bouquet" of miRNAs with significant upregulation variations in patients with major depressive disorder, suggesting further research to determine their suitability for personalization and evaluation, ultimately becoming integral components of major depression serological evaluations.

Hypericum perforatum L. attenuates depression by regulating Akkermansia muciniphila, tryptophan metabolism and NFκB-NLRP2-Caspase1-IL1β pathway

BACKGROUND

Gut microbiota dysbiosis significantly contributes to progression of depression. Hypericum perforatum L. (HPL) is traditionally used in Europe for treating depression. However, its mechanism remains largely underexplored.

PURPOSE

This study aims to investigate the pivotal gut microbiota species and microbial signaling metabolites associated with the antidepressant effects of HPL.

METHODS

Fecal microbiota transplantation was used to assess whether HPL mitigates depression through alterations in gut microbiota. Microbiota and metabolic profiling of control, chronic restraint stress (CRS)-induced depression, and HPL-treated CRS mice were examined using 16S rRNA gene sequencing and metabolomics analysis. The influence of gut microbiota on HPL's antidepressant effects was assessed by metabolite and bacterial intervention experiments.

RESULTS

HPL significantly alleviated depression symptoms in a manner dependent on gut microbiota and restored gut microbial composition by enriching Akkermansia muciniphila (AKK). Metabolomic analysis indicated that HPL regulated tryptophan metabolism, reducing kynurenine (KYN) levels derived from microbiota and increasing 5-hydroxytryptophan (5-HTP) levels. Notably, supplementation with KYN activated the NFκB-NLRP2-Caspase1-IL1β pathway and increased proinflammatory IL1β in the hippocampus of mice with depression. Interestingly, mono-colonization with AKK notably increased 5-hydroxytryptamine (5-HT) and decreased KYN levels, ameliorating depression symptoms through modulation of the NFκB-NLRP2-Caspase1-IL1β pathway.

CONCLUSIONS

The promising therapeutic role of HPL in treating depression is primarily attributed to its regulation of the NFκB-NLRP2-Caspase1-IL1β pathway, specifically by targeting AKK and tryptophan metabolites.

Ketamine's mechanism of action with an emphasis on neuroimmune regulation: can the complement system complement ketamine's antidepressant effects?

Over 300 million people worldwide suffer from major depressive disorder (MDD). Unfortunately, only 30-40% of patients with MDD achieve complete remission after conventional monoamine antidepressant therapy. In recent years, ketamine has revolutionized the treatment of MDD, with its rapid antidepressant effects manifesting within a few hours as opposed to weeks with conventional antidepressants. Many research endeavors have sought to identify ketamine's mechanism of action in mood disorders; while many studies have focused on ketamine's role in glutamatergic modulation, several studies have implicated its role in regulating neuroinflammation. The complement system is an important component of the innate immune response vital for synaptic plasticity. The complement system has been implicated in the pathophysiology of depression, and studies have shown increases in complement component 3 (C3) expression in the prefrontal cortex of suicidal individuals with depression. Given the role of the complement system in depression, ketamine and the complement system's abilities to modulate glutamatergic transmission, and our current understanding of ketamine's anti-inflammatory properties, there is reason to suspect a common link between the complement system and ketamine's mechanism of action. This review will summarize ketamine's anti- inflammatory roles in the periphery and central nervous system, with an emphasis on complement system regulation.

Understanding profiles of patients with treatment-resistant depression by stringency of health plan prior authorization criteria for approval of esketamine nasal spray

OBJECTIVES

In the United States (US), prescription drug coverage is subject to prior authorization (PA) criteria, which may vary between health plans and may exceed drug label requirements. This study aimed to characterize profiles and treatment history of patients with treatment-resistant depression (TRD) who initiated esketamine nasal spray, by stringency of their health plans' PA criteria relative to the esketamine label.

METHODS

Adults with evidence of TRD (≥2 antidepressant courses of adequate dose and duration) prior to initiating esketamine were identified using US insurance claims data (03/2016-02/2022). Based on health plan PA criteria for esketamine obtained from Managed Markets Insight & Technology data (05/2020-02/2022), patients were grouped into stringent (PA criteria exceeds label) and non-stringent (PA criteria less stringent or equal to label) cohorts. Patient treatment history before esketamine initiation was compared using Wilcoxon rank sum and Fisher's exact tests.

RESULTS

The stringent cohort included 168 patients (mean age: 45 years, 63% female) and the non-stringent cohort included 400 patients (mean age: 45 years, 70% female). During the ongoing major depressive episode before esketamine initiation, the stringent versus non-stringent cohort completed 3.9 versus 3.8 antidepressant treatment courses, on average (p = 0.217); 94.6% versus 96.8% used augmentation therapy (p = 0.240), including 59.3% versus 58.1% with an antipsychotic (p = 0.844), respectively.

CONCLUSIONS

Regardless of health plan stringency, on average, patients exceeded US label-mandated number of antidepressant trials before esketamine initiation, which questions the need for health insurance plans PA criteria above label.

Scientific guidelines for preclinical research on potentised preparations manufactured according to current pharmacopoeias-the PrePoP guidelines

OBJECTIVE

Pharmacopoeias regulate the manufacture of potentised pharmaceutical preparations used in different branches of complementary and integrative medicine. The physicochemical properties and biological activity of these preparations are often investigated in preclinical research, yet no guidelines for experimental research currently exist in this area. The present PrePoP guidelines aim to provide recommendations to promote high-quality, statistically sound, and reproducible preclinical research on potentised preparations.

METHODS

Input was gathered from researchers nominated by the relevant scientific societies using a simplified Delphi consensus approach covering the most relevant aspects of basic research methodology in the field including appropriate controls, sample preparation and handling, and statistics. After three rounds of feedback, a consensus was finally reached on the most important aspects and considerations for conducting high-quality research on potentised preparations.

RESULTS

We present a series of recommendations on a range of topics including experimental controls, system stability, blinding and randomisation, environmental influences, and procedures for the preparation of potentised samples and controls, and we address some specific challenges of this research field.

CONCLUSION

This expert consensus process resulted in a robust set of methodological guidelines for research on potentised preparations and provides a valuable framework that will inform and improve the quality of subsequent research in this emerging field.

PLEASE CITE THIS ARTICLE AS

Tournier AL, Bonamin LV, Buchheim-Schmidt S, Cartwright S, Dombrowsky C, Doesburg P, Holandino C, Kokornaczyk MO, van de Kraats EB, López-Carvallo JA, Nandy P, Mazón-Suástegui JM, Mirzajani F, Poitevin B, Scherr C, Thieves K, Würtenberger S, Baumgartner S. Scientific guidelines for preclinical research on potentised preparations manufactured according to current pharmacopoeias-the PrePoP guidelines. J Integr Med. 2024; 22(5): 533-544.

Ketamine treatment for anhedonia in unipolar and bipolar depression: a systematic review

Ketamine, an N-methyl-D-aspartate receptor antagonist, is a racemic mixture of esketamine and arketamine used to treat unipolar and bipolar depression. Preliminary reports indicate that it may be beneficial for depressed patients reporting symptoms of anhedonia. In this systematic review we aim to assess and analyze the existing body of evidence regarding the therapeutic effects of ketamine on the domain of anhedonia. Electronic databases (PubMed, APA Psycinfo and Web of Science) were searched from inception to November 2023. Protocol was registered in PROSPERO under the identifier CRD42023476603. A total of twenty-two studies, including four randomized-controlled trials and eighteen open-label trials were included. All studies reported alleviation of anhedonia symptoms following ketamine or esketamine administration, regardless of the number of infusions. Several important limitations were included, first and foremost low number of placebo-controlled randomized-controlled trials. This review indicates a potential anti-anhedonic effect of ketamine in patients with depression. Several trials used neuroimaging techniques which confirm ketamine's effect on functional connectivity correlating with the improvement in anhedonia. Despite considerable variations in methodology and the specific brain regions investigated, these studies collectively point towards ketamine's neuroplastic effects in mitigating anhedonia.

Genetic factors and symptom dimensions associated with antidepressant treatment outcomes: clues for new potential therapeutic targets?

Treatment response and resistance in major depressive disorder (MDD) show a significant genetic component, but previous studies had limited power also due to MDD heterogeneity. This literature review focuses on the genetic factors associated with treatment outcomes in MDD, exploring their overlap with those associated with clinically relevant symptom dimensions. We searched PubMed for: (1) genome-wide association studies (GWASs) or whole exome sequencing studies (WESs) that investigated efficacy outcomes in MDD; (2) studies examining the association between MDD treatment outcomes and specific depressive symptom dimensions; and (3) GWASs of the identified symptom dimensions. We identified 13 GWASs and one WES of treatment outcomes in MDD, reporting several significant loci, genes, and gene sets involved in gene expression, immune system regulation, synaptic transmission and plasticity, neurogenesis and differentiation. Nine symptom dimensions were associated with poor treatment outcomes and studied by previous GWASs (anxiety, neuroticism, anhedonia, cognitive functioning, melancholia, suicide attempt, psychosis, sleep, sociability). Four genes were associated with both treatment outcomes and these symptom dimensions: CGREF1 (anxiety); MCHR1 (neuroticism); FTO and NRXN3 (sleep). Other overlapping signals were found when considering genes suggestively associated with treatment outcomes. Genetic studies of treatment outcomes showed convergence at the level of biological processes, despite no replication at gene or variant level. The genetic signals overlapping with symptom dimensions of interest may point to shared biological mechanisms and potential targets for new treatments tailored to the individual patient's clinical profile.

Multimodal brain-derived subtypes of Major depressive disorder differentiate patients for anergic symptoms, immune-inflammatory markers, history of childhood trauma and treatment-resistance

An estimated 30 % of Major Depressive Disorder (MDD) patients exhibit resistance to conventional antidepressant treatments. Identifying reliable biomarkers of treatment-resistant depression (TRD) represents a major goal of precision psychiatry, which is hampered by the clinical and biological heterogeneity. To uncover biologically-driven subtypes of MDD, we applied an unsupervised data-driven framework to stratify 102 MDD patients on their neuroimaging signature, including extracted measures of cortical thickness, grey matter volumes, and white matter fractional anisotropy. Our novel analytical pipeline integrated different machine learning algorithms to harmonize data, perform data dimensionality reduction, and provide a stability-based relative clustering validation. The obtained clusters were characterized for immune-inflammatory peripheral biomarkers, TRD, history of childhood trauma and depressive symptoms. Our results indicated two different clusters of patients, differentiable with 67 % of accuracy: one cluster (n = 59) was associated with a higher proportion of TRD, and higher scores of energy-related depressive symptoms, history of childhood abuse and emotional neglect; this cluster showed a widespread reduction in cortical thickness (d = 0.43-1.80) and volumes (d = 0.45-1.05), along with fractional anisotropy in the fronto-occipital fasciculus, stria terminalis, and corpus callosum (d = 0.46-0.52); the second cluster (n = 43) was associated with cognitive and affective depressive symptoms, thicker cortices and wider volumes. Multivariate analyses revealed distinct brain-inflammation relationships between the two clusters, with increase in pro-inflammatory markers being associated with decreased cortical thickness and volumes. Our stratification of MDD patients based on structural neuroimaging identified clinically-relevant subgroups of MDD with specific symptomatic and immune-inflammatory profiles, which can contribute to the development of tailored personalized interventions for MDD.

The Impact of a Diet Rich in Omega-3 Fatty Acids on the Quality of Life of Patients with Squamous Cell Lung Cancer and Comorbid Depression: A Retrospective Study

BACKGROUND

Lung cancer is a significant health concern, and is often accompanied by comorbid depression, leading to worsened prognosis and decreased quality of life for patients. This study aimed to investigate the potential influence of a diet rich in Omega-3 fatty acids on the quality of life of patients with squamous cell lung cancer and comorbid depression.

METHODS

A retroactive analysis of clinical information from patients with squamous cell lung cancer and comorbid depression admitted to Hongqi Hospital Affiliated to Mudanjiang Medical University from June 2022 to June 2023 was conducted. The patients were classified into two groups on the basis of different dietary care approaches: the Routine Dietary Group and the Omega-3 Fatty Acids Group. Baseline characteristics, pulmonary function tests, dietary intake, depression scoring, and quality of life scores were compared between the two groups.

RESULTS

103 patients in total were included, with 51 in the Routine Dietary Group and 52 in the Omega-3 Fatty Acids Group. The Omega-3 Fatty Acids Group exhibited significantly higher ingestion of Omega-3 fatty acids in comparison with the Routine Dietary Group (3.15 ± 0.64 g/day vs. 2.93 ± 0.28 g/day, p = 0.022). Despite similar baseline pulmonary function tests, patients in the Omega-3 Fatty Acids Group showed significantly higher scores in physical (70.17 ± 4.81 vs. 68.18 ± 5.03, p = 0.043) and emotional (71.29 ± 4.58 vs. 69.38 ± 4.25, p = 0.030) functioning, as well as lower scores in insomnia (27.41 ± 4.51 vs. 29.34 ± 4.21, p = 0.027) and constipation (7.34 ± 1.66 vs. 8.43 ± 3.36, p = 0.040).

CONCLUSION

The study provided insights into the potential impact of a diet rich in Omega-3 fatty acids on the quality of life of patients with squamous cell lung cancer and complicating depression, suggesting that dietary interventions emphasizing Omega-3 fatty acids may be conducive to improving physical and emotional functioning, as well as symptom management, in this patient population.

Development of a harmonized sociodemographic and clinical questionnaire for mental health research: A Delphi-method-based consensus recommendation

OBJECTIVE

Harmonized tools are essential for reliable data sharing and accurate identification of relevant factors in mental health research. The primary objective of this study was to create a harmonized questionnaire to collect demographic, clinical and behavioral data in diverse clinical trials in adult psychiatry.

METHODS

We conducted a literature review and examined 24 questionnaires used in previously published randomized controlled trials in psychiatry, identifying a total of 27 domains previously explored. Using a Delphi-method process, a task force team comprising experts in psychiatry, epidemiology and statistics selected 15 essential domains for inclusion in the final questionnaire.

RESULTS

The final selection resulted in a concise set of 22 questions. These questions cover factors such as age, sex, gender, ancestry, education, living arrangement, employment status, home location, relationship status, and history of medical and mental illness. Behavioral factors like physical activity, diet, smoking, alcohol and illicit drug use were also included, along with one question addressing family history of mental illness. Income was excluded due to high confounding and redundancy, while language was included as a measure of migration status.

CONCLUSION

The recommendation and adoption of this harmonized tool for the assessment of demographic, clinical and behavioral data in mental health research can enhance data consistency and enable comparability across clinical trials.

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.

Metabolic activity of CYP2C19 and CYP2D6 on antidepressant response from 13 clinical studies using genotype imputation: a meta-analysis

Cytochrome P450 enzymes including CYP2C19 and CYP2D6 are important for antidepressant metabolism and polymorphisms of these genes have been determined to predict metabolite levels. Nonetheless, more evidence is needed to understand the impact of genetic variations on antidepressant response. In this study, individual clinical and genetic data from 13 studies of European and East Asian ancestry populations were collected. The antidepressant response was clinically assessed as remission and percentage improvement. Imputed genotype was used to translate genetic polymorphisms to metabolic phenotypes (poor, intermediate, normal, and rapid+ultrarapid) of CYP2C19 and CYP2D6. CYP2D6 structural variants cannot be imputed from genotype data, limiting the determination of metabolic phenotypes, and precluding testing for association with response. The association of CYP2C19 metabolic phenotypes with treatment response was examined using normal metabolizers as the reference. Among 5843 depression patients, a higher remission rate was found in CYP2C19 poor metabolizers compared to normal metabolizers at nominal significance but did not survive after multiple testing correction (OR = 1.46, 95% CI [1.03, 2.06], p = 0.033, heterogeneity I2 = 0%, subgroup difference p = 0.72). No metabolic phenotype was associated with percentage improvement from baseline. After stratifying by antidepressants primarily metabolized by CYP2C19, no association was found between metabolic phenotypes and antidepressant response. Metabolic phenotypes showed differences in frequency, but not effect, between European- and East Asian-ancestry studies. In conclusion, metabolic phenotypes imputed from genetic variants using genotype were not associated with antidepressant response. CYP2C19 poor metabolizers could potentially contribute to antidepressant efficacy with more evidence needed. Sequencing and targeted pharmacogenetic testing, alongside information on side effects, antidepressant dosage, depression measures, and diverse ancestry studies, would more fully capture the influence of metabolic phenotypes.

Overcoming treatment-resistant depression with machine-learning based tools: a study protocol combining EEG and clinical data to personalize glutamatergic and brain stimulation interventions (SelecTool Project)

Treatment-Resistant Depression (TRD) poses a substantial health and economic challenge, persisting as a major concern despite decades of extensive research into novel treatment modalities. The considerable heterogeneity in TRD's clinical manifestations and neurobiological bases has complicated efforts toward effective interventions. Recognizing the need for precise biomarkers to guide treatment choices in TRD, herein we introduce the SelecTool Project. This initiative focuses on developing (WorkPlane 1/WP1) and conducting preliminary validation (WorkPlane 2/WP2) of a computational tool (SelecTool) that integrates clinical data, neurophysiological (EEG) and peripheral (blood sample) biomarkers through a machine-learning framework designed to optimize TRD treatment protocols. The SelecTool project aims to enhance clinical decision-making by enabling the selection of personalized interventions. It leverages multi-modal data analysis to navigate treatment choices towards two validated therapeutic options for TRD: esketamine nasal spray (ESK-NS) and accelerated repetitive Transcranial Magnetic Stimulation (arTMS). In WP1, 100 subjects with TRD will be randomized to receive either ESK-NS or arTMS, with comprehensive evaluations encompassing neurophysiological (EEG), clinical (psychometric scales), and peripheral (blood samples) assessments both at baseline (T0) and one month post-treatment initiation (T1). WP2 will utilize the data collected in WP1 to train the SelecTool algorithm, followed by its application in a second, out-of-sample cohort of 20 TRD subjects, assigning treatments based on the tool's recommendations. Ultimately, this research seeks to revolutionize the treatment of TRD by employing advanced machine learning strategies and thorough data analysis, aimed at unraveling the complex neurobiological landscape of depression. This effort is expected to provide pivotal insights that will promote the development of more effective and individually tailored treatment strategies, thus addressing a significant void in current TRD management and potentially reducing its profound societal and economic burdens.

Low doses of acetaminophen produce antidepressive-like effects through the opioid system in mice

Acetaminophen (paracetamol) is one of the most popular analgesics for the management of fever and pain but few reports have investigated its antidepressant-like effect. Moreover, the role of the opioidergic pathway has been indicated in depression pathophysiology. This study aimed to examine the involvement of the opioid receptors in the antidepressant-like effect of acetaminophen after acute and sub-chronic administration using mice forced swimming test (FST). Our finding showed that administration of acetaminophen (50 and 100 mg/kg, i.p.) 30 min before the FST produced an antidepressant effect which was reduced by naloxone (1 mg/kg, i.p., a nonselective opioid receptor antagonist). Moreover, we observed that acetaminophen in higher doses (200 and 400 mg/kg) was ineffective. Also, the response of the non-effective dose of acetaminophen (25 mg/kg) was potentiated by the non-effective dose of morphine (0.1 mg/kg) in the FST that was antagonized by naloxone. Also, in contrast to morphine (10 mg/kg), acetaminophen (100 mg/kg, i.p.) induced neither tolerance to the anti-immobility behavior nor withdrawal syndrome after repeated administration. In addition, RT-PCR showed that hippocampal mu- and kappa-opioid receptor mRNA expression increased in mice after repeated administration of acetaminophen; however, morphine therapy for 6 days did not affect kappa-opioid receptor expression. Our findings demonstrated that acetaminophen in lower doses but not high doses revealed an antidepressant-like activity without inducing tolerance and withdrawal syndromes. Moreover, the observed effect of acetaminophen may be via altering the opioid system, particularly hippocampal mu- and kappa-receptors.

Psilocybin for dementia prevention? The potential role of psilocybin to alter mechanisms associated with major depression and neurodegenerative diseases

Major depression is an established risk factor for subsequent dementia, and depression in late life may also represent a prodromal state of dementia. Considering current challenges in the clinical development of disease modifying therapies for dementia, the focus of research is shifting towards prevention and modification of risk factors to alter the neurodegenerative disease trajectory. Understanding mechanistic commonalities underlying affective symptoms and cognitive decline may reveal biomarkers to aid early identification of those at risk of progressing to dementia during the preclinical phase of disease, thus allowing for timely intervention. Adult hippocampal neurogenesis (AHN) is a phenomenon that describes the birth of new neurons in the dentate gyrus throughout life and it is associated with spatial learning, memory and mood regulation. Microglia are innate immune system macrophages in the central nervous system that carefully regulate AHN via multiple mechanisms. Disruption in AHN is associated with both dementia and major depression and microgliosis is a hallmark of several neurodegenerative diseases. Emerging evidence suggests that psychedelics promote neuroplasticity, including neurogenesis, and may also be immunomodulatory. In this context, psilocybin, a serotonergic agonist with rapid-acting antidepressant properties has the potential to ameliorate intersecting pathophysiological processes relevant for both major depression and neurodegenerative diseases. In this narrative review, we focus on the evidence base for the effects of psilocybin on adult hippocampal neurogenesis and microglial form and function; which may suggest that psilocybin has the potential to modulate multiple mechanisms of action, and may have implications in altering the progression from major depression to dementia in those at risk.

Real-world demographic and clinical profiles of patients with treatment-resistant depression initiated on esketamine nasal spray

OBJECTIVE

ESKALE is a French, multicentre, observational study of adults with treatment-resistant depression (TRD) treated with esketamine. This interim analysis describes baseline demographic and clinical characteristic evolution in patients included and treated from early access program to post-marketing launch.

METHODS

Data were collected from medical records and included patient characteristics, disease history at esketamine initiation, use of neurostimulation, the patient's care pathway, and the number of antidepressant treatment lines prescribed prior to esketamine initiation. Descriptive statistics were used for each cohort: the early access program 'Temporary Authorisation for Use' (ATU), post-ATU, and post-launch cohorts.

RESULTS

The overall ESKALE cohort (N = 160 included; n = 157 treated with esketamine; average age 49.0 years; 66.2% female) demonstrated moderate-to-severe depression according to clinical assessment and a mean Montgomery-Åsberg Depression Rating Scale score of 32.6 (8.0); however, severity, subtype, and comorbidities were heterogeneous across the cohorts. Earlier use of esketamine and prior to alternative treatments occurred during the later cohorts.

CONCLUSION

These findings demonstrated a high burden of TRD in these patients and that esketamine is used in TRD treatment regardless of their disease severity, subtype, or existing comorbidities. These results also suggest that esketamine is potentially a clinically useful alternative treatment, particularly with healthcare professionals gaining greater familiarity with and easier access to esketamine.

Safety and efficacy of repetitive stimulation of the left dorsolateral prefrontal cortex using transcranial focused ultrasound in treatment-resistant depressed patients: A non-inferiority randomized controlled trial protocol

BACKGROUND

About 30% of patients diagnosed with major depressive disorder fail with the mainstream pharmacological treatment. Patients who do not achieve clinical remission of symptoms, even with two different antidepressants, are classified with treatment-resistant depression (TDR). This condition imposes an additional burden with increased Disability Adjusted Life Years. Therefore, complementary treatments, such as neuromodulation, are necessary. The transcranial focused ultrasound (tFUS) has emerged in the past few years as a reliable method for non-invasive neuromodulation in humans and may help treat TRD. This study aims to propose a research protocol for a non-inferiority randomized clinical trial of TDR with tFUS.

METHODS

Patients with documented TRD will be screened upon entering the TRD outpatient clinic at UFMG (Brazil). One hundred patients without a clinical history of other psychiatric illness, anatomical abnormalities on magnetic resonance imaging (MRI), or treatment with electroconvulsive therapy will be invited to participate. Patients will be randomized (1:1) into two groups: 1) treatment with a previously established protocol of transcranial magnetic stimulation; and 2) treatment with a similar protocol using the stimulation. Besides regular consultations in the outpatient clinic, both groups will attend 7 protocolled spaced days of brain stimulation targeted at the left dorsolateral prefrontal cortex. They will also be submitted to 4 sessions of image studies (2 MRIs, 2 positron-emission tomography), 3 of neuropsychological assessments (at baseline, 1 week and 2 months after treatment), the Montgomery-Åsberg Depression Rating Scale to analyze the severity of depressive symptoms.

DISCUSSION

This clinical trial intends to verify the safety and clinical efficacy of tFUS stimulation of the dorsolateral prefrontal cortex of patients with TRD, compared with a previously established neuromodulation method.

Low-dose interleukin 2 antidepressant potentiation in unipolar and bipolar depression: Safety, efficacy, and immunological biomarkers

Immune-inflammatory mechanisms are promising targets for antidepressant pharmacology. Immune cell abnormalities have been reported in mood disorders showing a partial T cell defect. Following this line of reasoning we defined an antidepressant potentiation treatment with add-on low-dose interleukin 2 (IL-2). IL-2 is a T-cell growth factor which has proven anti-inflammatory efficacy in autoimmune conditions, increasing thymic production of naïve CD4 + T cells, and possibly correcting the partial T cell defect observed in mood disorders. We performed a single-center, randomised, double-blind, placebo-controlled phase II trial evaluating the safety, clinical efficacy and biological responses of low-dose IL-2 in depressed patients with major depressive (MDD) or bipolar disorder (BD). 36 consecutively recruited inpatients at the Mood Disorder Unit were randomised in a 2:1 ratio to receive either aldesleukin (12 MDD and 12 BD) or placebo (6 MDD and 6 BD). Active treatment significantly potentiated antidepressant response to ongoing SSRI/SNRI treatment in both diagnostic groups, and expanded the population of T regulatory, T helper 2, and percentage of Naive CD4+/CD8 + immune cells. Changes in cell frequences were rapidly induced in the first five days of treatment, and predicted the later improvement of depression severity. No serious adverse effect was observed. This is the first randomised control trial (RCT) evidence supporting the hypothesis that treatment to strengthen the T cell system could be a successful way to correct the immuno-inflammatory abnormalities associated with mood disorders, and potentiate antidepressant response.

Altered functional brain activity in first-episode major depressive disorder treated with electro-acupuncture: A resting-state functional magnetic resonance imaging study

Background

Previous studies have found electroacupuncture could improve the clinical symptoms of first-episode major depressive disorder (MDD), but the exact neural mechanism of action needs to be further elucidated.

Methods

Twenty-eight first-episode MDD patients were randomly divided into 14 electro-acupuncture stimulation (EAS) groups and 14 sham-acupuncture stimulation (SAS) groups, and clinical symptoms were assessed and functional magnetic resonance imaging (fMRI) scans were done in both groups. Amplitude of low-frequency fluctuations (ALFF) was used to observe the changes between the pre-treatment and post-treatment in the two groups, and the altered brain areas were selected as region of interest (ROI) to observe the FC changes. Meanwhile, the correlation between the altered clinical symptoms and the altered ALFF and FC of brain regions in the two groups was analyzed.

Results

The EAS significantly decreased the HAMD-24 and HAMA-14 scores of MDD than SAS group. The imaging results revealed that both groups were able to increase the ALFF of the left middle temporal gyrus and the left cerebellar posterior lobe. When using the left middle temporal gyrus and the left posterior cerebellar lobe as ROIs, EAS group increased the FC between the left middle temporal gyrus with the left superior frontal gyrus, the left middle frontal gyrus, and the left hippocampus, and decreased the FC between the left posterior cerebellar lobe and the left calcarine gyrus, while SAS group only increased the FC between the left middle temporal gyrus with the left superior frontal gyrus. The alternations in clinical symptoms after EAS treatment were positively correlated with the altered ALFF values in the left middle temporal gyrus and the altered FC values in the left middle temporal gyrus and the left middle frontal gyrus.

Conclusion

EA demonstrates modulation of functional activity in the default mode network (DMN), sensorimotor network (SMN), cognitive control network (CCN), limbic system, and visual network (VN) for the treatment of the first-episode MDD. Our findings contribute to the neuroimaging evidence for the efficacy of EAS.

Higher Seasonal Variation of Systemic Inflammation in Bipolar Disorder

Seasonal rhythms affect the immune system. Evidence supports the involvement of immuno-inflammatory mechanisms in bipolar disorder (BD), with the neutrophil to lymphocyte ratio (NLR), and the systemic immune-inflammatory index (SII; platelets × neutrophils/lymphocytes) consistently reported to be higher in patients with BD than in HC, but seasonal rhythms of innate and adaptive immunity have never been studied. We retrospectively studied NLR and SII in 824 participants divided into three groups: 321 consecutively admitted inpatients affected by a major depressive episode in course of BD, and 255 consecutively admitted inpatients affected by obsessive-compulsive disorder (OCD; positive psychiatric control), and 248 healthy controls (HC). Patients with BD showed markedly higher markers of systemic inflammation in autumn and winter, but not in spring and summer, in respect to both HC and patients with OCD, thus suggesting a specific effect of season on inflammatory markers in BD, independent of a shared hospital setting and drug treatment. Given that systemic inflammation is emerging as a new marker and as target for treatment in depressive disorders, we suggest that seasonal rhythms should be considered for tailoring antidepressant immuno-modulatory treatments in a precision medicine approach.

Ketamine in multiple treatment-resistant depressed inpatients: A naturalistic cohort study

BACKGROUND

Ketamine has emerged as an effective treatment option for patients with treatment-resistant depression. However, there is limited evidence of the benefits of ketamine in inpatients with multiple treatment resistance (MTR), who far exceed the formal criteria for treatment resistance and suffer from extensive psychiatric comorbidities.

OBJECTIVE

The aim of this naturalistic study was to provide preliminary evidence for the use of ketamine in the treatment of MTR depression in a naturalistic inpatient setting.

METHODS

Seventy-seven patients (mean age 45.1 ± 13.8 years) were treated with intravenous or intranasal ketamine (1068 administrations) twice weekly for five weeks, followed by maintenance therapy if clinically indicated. Treatment effects were assessed with the BDI, and side effects were assessed by clinicians. We analyzed dose- and route of application-related changes in depression severity, response and remission rates as well as effects on suicidality and frequency of adverse events.

RESULTS

Depression severity and suicidality decreased in the acute treatment phase and these changes persisted during the maintenance therapy phase. A total of 28.9 % of the patients met the criteria for response, and 15 % met the criteria for remission. The initial treatment response was highly predictive of the outcome at the end of the acute treatment phase. None of the reported side effects required medical intervention. High-dose intravenous ketamine (0.75-1 mg/kg) resulted in the most pronounced clinical effects.

LIMITATIONS

This observational, retrospective, and naturalistic study may be subject to bias and did not allow control of external variables.

CONCLUSIONS

We outlined a clinically feasible, high-dose ketamine treatment regimen for hospitalized patients with MTR depression.

How different definition criteria may predict clinical outcome in treatment resistant depression: Results from a prospective real-world study

Management of treatment-resistant depression (TRD) remains a major public health challenge, also due to the lack of a consensus around TRD definition. We investigated the impact of different definitions of TRD on identifying patients with distinct features in terms of baseline characteristics, treatment strategies, and clinical outcome. We conducted a prospective naturalistic study on 538 depressed inpatients. Patients were screened for treatment resistance by two TRD definitions: looser criteria (lTRD) and stricter criteria (sTRD). We compared baseline characteristics, treatment and clinical outcome between the TRD groups and their non-TRD counterparts. 52.97 % of patients were identified as lTRD, only 28.81 % met the criteria for sTRD. sTRD patients showed lower rates of remission and slower symptom reduction compared to non-TRD patients and received more challenging treatments. Surprisingly, patients identified as sTRD also exhibited lower rates of psychiatric comorbidities, including personality disorders, substance abuse, or alcohol misuse. Stricter TRD criteria identify patients with worse clinical outcomes. Looser criteria may lead to overdiagnosis and over treatment. Clinical features known to be possible risk factors for TRD, as psychiatric comorbidities, showed to be more suggestive of a "difficult to manage" depression rather than a proper TRD.

Linking connectivity of deep brain stimulation of nucleus accumbens area with clinical depression improvements: a retrospective longitudinal case series

Treatment-resistant depression is a severe form of major depressive disorder and deep brain stimulation is currently an investigational treatment. The stimulation's therapeutic effect may be explained through the functional and structural connectivities between the stimulated area and other brain regions, or to depression-associated networks. In this longitudinal, retrospective study, four female patients with treatment-resistant depression were implanted for stimulation in the nucleus accumbens area at our center. We analyzed the structural and functional connectivity of the stimulation area: the structural connectivity was investigated with probabilistic tractography; the functional connectivity was estimated by combining patient-specific stimulation volumes and a normative functional connectome. These structural and functional connectivity profiles were then related to four clinical outcome scores. At 1-year follow-up, the remission rate was 66%. We observed a consistent structural connectivity to Brodmann area 25 in the patient with the longest remission phase. The functional connectivity analysis resulted in patient-specific R-maps describing brain areas significantly correlated with symptom improvement in this patient, notably the prefrontal cortex. But the connectivity analysis was mixed across patients, calling for confirmation in a larger cohort and over longer time periods.

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.

Depression risk in chronic tonsillitis patients underwent tonsillectomy: a global federated health network analysis

Background: Tonsillectomy is a common surgery in the US, with possible postoperative complications. While small studies indicate postoperative depressive symptoms may occur, large-scale evidence is lacking on the tonsillectomy-depression link. Methods: We conducted a retrospective cohort study using the TriNetX US collaborative network, offering de-identified electronic health data from 59 collaborative healthcare organizations (HCOs) in the United States. In this study, people being diagnosed of chronic tonsillitis between January 2005 and December 2017 were enrolled. Patients deceased, with previous record of cancers or psychiatric events before index date were excluded. 14,874 chronic tonsillitis patients undergoing tonsillectomy were propensity score matched 1:1 to controls for age, sex, and race. New-onset depression risks were evaluated over 5 years post-tonsillectomy and stratified by age and sex. Confounders were adjusted for including demographics, medications, comorbidities and socioeconomic statuses. Results: After matching, the difference of key baseline characteristics including age, sex, comedications status and obesity status was insignificant between tonsillectomy and non-tonsillectomy groups. Tonsillectomy had a 1.29 times higher 5-year depression risk versus matched controls (95% CI, 1.19-1.40), with elevated risks seen at 1 year (HR=1.51; 95% CI, 1.28-1.79) and 3 years (HR=1.30; 95% CI, 1.18-1.43). By stratifications, risks were increased for both males (HR=1.30; 95% CI, 1.08-1.57) and females (HR=1.30; 95% CI, 1.18-1.42), and significantly higher in ages 18-64 years (HR=1.37; 1.26-1.49), but no significance observed for those 65 years and older. After performing sensitivity analyses and applying washout periods of 6, 12, and 36 months, the outcome remained consistent with unadjusted results. Conclusion: This real-world analysis found tonsillectomy was associated with a 30% higher 5-year depression risk versus matched non-tonsillectomy patients with chronic tonsillitis. Further mechanistic research is needed to clarify the pathophysiologic association between depression and tonsillectomy. Depression is not commonly mentioned in the current post-tonsillectomy care realm; however, the outcome of our study emphasized the possibility of these suffering condition after operation. Attention to psychological impacts following tonsillectomy is warranted to support patient well-being, leading to better management of post-tonsillectomy individuals.

The rapid antidepressant effectiveness of repeated dose of intravenous ketamine and intranasal esketamine: A post-hoc analysis of pooled real-world data

INTRODUCTION

Intravenous ketamine (KET-IV) and intranasal esketamine (ESK-NS) are effective in the acute treatment of Treatment-Resistant Depression (TRD). Studies comparing KET-IV and ESK-NS concerning their action, safety, and tolerability are currently lacking.

MATERIALS AND METHODS

We combined patients' data from two unipolar TRD cohorts that received KET-IV (n = 171) at the Canadian Rapid Treatment Center of Excellence in Toronto, Canada, or ESK-NS (n = 140) at several TRD clinics in Italy. The Quick Inventory for Depression Symptomatology-Self-Report-16/QIDS-SR16 in the KET-IV group and Montgomery-Åsberg Depression Rating Scale/MADRS in the ESK-NS group measured depressive symptoms at baseline (T0) and after the acute treatment phase (T1) (i.e., four infusions of KET-IV and eight administrations of ESK-NS). As different scales were used, the primary outcome was to compare the improvement in depression severity in the two cohorts by measuring effect sizes, response and remission rates. Finally, we compare side effects and discontinuation rates.

RESULTS

At T1, KET-IV and ESK-NS significantly reduced depressive symptoms (respectively: QIDS-SR16 mean reduction = 5.65, p < 0.001; MADRS mean reduction = 11.41, p = 0.025). KET-IV showed larger effect sizes compared to ESK-NS (1.666 vs. 1.244). KET-IV had higher response rates (36 % vs. 25 %; p = 0.042) but not superior remission rates (13 % vs. 12 %; p = 0.845) than ESK-NS at T1. Despite more reported side effects, KET-IV did not cause more discontinuations for adverse events (4.6 % vs. 2.12 %; p = 0.228) than ESK-NS.

CONCLUSION

KET-IV showed a higher short-term antidepressant effect, whereas ESK-NS exhibited lower side effects. Both were generally well tolerated. Future head-to-head studies should consider the long-term efficacy of these treatments.

Treating Treatment-resistant Depression with Esketamine Nasal Spray When All Therapeutic Options Have Been Exhausted: Clinical Experience from a Spanish Cohort of Expanded Use

Objective

: Treatment Resistant Depression (TRD) is commonly defined as the lack of response to two or more anti-depressants with different mechanisms of action. Up to 30% of patients diagnosed with major depressive disorder might be considered to present TRD. The objective of this study was to assess the effectiveness and tolerability of esketamine in patients diagnosed with TRD, who were referred to our program after exhausting all available treatments. A secondary objective consisted in researching the relationship between response and previous use of electroconvulsive therapy.

Methods

: A prospective, observational study was carried out in patients enrolled in the expanded use of esketamine in our center. They received esketamine prior to its marketing authorisation, for therapeutic purposes. Sixteen subjects were analyzed. Effectiveness was assessed with the Montgomery-Asberg depression rating scale (MADRS). Patients were followed up to 4 months after the administration.

Results

: Esketamine showed a rapid, robust effect in improving depressive symptoms, with no specific correlation between outcome and any demographic or clinical traits evaluated. No differences were found between patients that previously received Electroconvulsive Therapy, and those that didn't. 10 out of 16 patients responded (＞ 50% change in baseline MADRS scores), but only five achieved remission (＜ 12 points in the global MADRS score). We provide some recommendations, based on clinical experience, to improve tolerability and adherence, and to manage adverse effects.

Conclusion

: Results suggest that esketamine is a safe, effective and rapid-acting option for TRD. More studies are needed to properly assess predictors of response outcome.

French Society for Biological Psychiatry and Neuropsychopharmacology (AFPBN) guidelines for the management of patients with partially responsive depression and treatment-resistant depression: Update 2024

INTRODUCTION

The purpose of this update is to add newly approved nomenclatures and treatments as well as treatments yet to be approved in major depressive disorder, thus expanding the discussions on the integration of resistance factors into the clinical approach.

METHODS

Unlike the first consensus guidelines based on the RAND/UCLA Appropriateness Method, the French Association for Biological Psychiatry and Neuropsychopharmacology (AFPBN) developed an update of these guidelines for the management of partially responsive depression (PRD) and treatment-resistant depression (TRD). The expert guidelines combine scientific evidence and expert clinicians' opinions to produce recommendations for PRD and TRD.

RESULTS

The recommendations addressed three areas judged as essential for updating the previous 2019 AFPBN guidelines for the management of patients with TRD: (1) the identification of risk factors associated with TRD, (2) the therapeutic management of patients with PRD and TRD, and (3) the indications, the modalities of use and the monitoring of recent glutamate receptor modulating agents (esketamine and ketamine).

CONCLUSION

These consensus-based guidelines make it possible to build bridges between the available empirical literature and clinical practice, with a highlight on the 'real world' of the clinical practice, supported by a pragmatic approach centred on the experience of specialised prescribers in TRD.

Impact of Adjunctive VNS on Drug Load, Depression Severity, and Number of Neuromodulatory Maintenance Treatments

Vagus nerve stimulation (VNS) is a long-term adjunctive treatment option in patients with difficult-to-treat depression (DTD). A total of n = 20 patients (mean age 52.6 years) were included in the multicenter, prospective, observational, naturalistic RESTORE-LIFE study and were treated with adjunctive VNS as an add-on to treatment as usual. Exploratory and secondary outcome parameters from a single center were investigated for this present analysis. The overall mean drug load slightly decreased from 4.5 at baseline to 4.4 at 12 months (Z = -0.534, p = 0.594). The drug load was lower in previous electroconvulsive therapy (ECT) responders than in non-responders. There was a reduction in the mean number of hospitalizations per month after VNS implantation (Z = 1.975, p = 0.048) and a significant decrease in the mean Montgomery Åsberg Depression Rating Scale (MADRS) score from 27.3 at baseline to 15.3 at 12 months (T = 4.230, degree of freedom (df) = 19, p = 0.001). A history of ECT response at baseline was associated with greater improvement in the MADRS score after 12 months of VNS (F = 8.171, p = 0.013). The number of neuromodulatory maintenance treatments decreased during the follow-up period. In summary, there was an alleviation in the burden of illness among DTD patients treated with VNS.

The definition of treatment resistance in anxiety disorders: a Delphi method-based consensus guideline

Anxiety disorders are very prevalent and often persistent mental disorders, with a considerable rate of treatment resistance which requires regulatory clinical trials of innovative therapeutic interventions. However, an explicit definition of treatment-resistant anxiety disorders (TR-AD) informing such trials is currently lacking. We used a Delphi method-based consensus approach to provide internationally agreed, consistent and clinically useful operational criteria for TR-AD in adults. Following a summary of the current state of knowledge based on international guidelines and an available systematic review, a survey of free-text responses to a 29-item questionnaire on relevant aspects of TR-AD, and an online consensus meeting, a panel of 36 multidisciplinary international experts and stakeholders voted anonymously on written statements in three survey rounds. Consensus was defined as ≥75% of the panel agreeing with a statement. The panel agreed on a set of 14 recommendations for the definition of TR-AD, providing detailed operational criteria for resistance to pharmacological and/or psychotherapeutic treatment, as well as a potential staging model. The panel also evaluated further aspects regarding epidemiological subgroups, comorbidities and biographical factors, the terminology of TR-AD vs. "difficult-to-treat" anxiety disorders, preferences and attitudes of persons with these disorders, and future research directions. This Delphi method-based consensus on operational criteria for TR-AD is expected to serve as a systematic, consistent and practical clinical guideline to aid in designing future mechanistic studies and facilitate clinical trials for regulatory purposes. This effort could ultimately lead to the development of more effective evidence-based stepped-care treatment algorithms for patients with anxiety disorders.

The contribution of polyamine pathway to determinations of diagnosis for treatment-resistant depression: A metabolomic analysis

OBJECTIVES

Approximately one-third of major depressive disorder (MDD) patients do not respond to standard antidepressants and develop treatment-resistant depression (TRD). We aimed to reveal metabolic differences and discover promising potential biomarkers in TRD.

METHODS

Our study recruited 108 participants including healthy controls (n = 40) and patients with TRD (n = 35) and first-episode drug-naive MDD (DN-MDD) (n = 33). Plasma samples were presented to ultra performance liquid chromatography-tandem mass spectrometry. Then, a machine-learning algorithm was conducted to facilitate the selection of potential biomarkers.

RESULTS

TRD appeared to be a distinct metabolic disorder from DN-MDD and healthy controls (HCs). Compared to HCs, 199 and 176 differentially expressed metabolites were identified in TRD and DN-MDD, respectively. Of all the metabolites that were identified, spermine, spermidine, and carnosine were considered the most promising biomarkers for diagnosing TRD and DN-MDD patients, with the resulting area under the ROC curve of 0.99, 0.99, and 0.93, respectively. Metabolic pathway analysis yielded compelling evidence of marked changes or imbalances in both polyamine metabolism and energy metabolism, which could potentially represent the primary altered pathways associated with MDD. Additionally, L-glutamine, Beta-alanine, and spermine were correlated with HAMD score.

CONCLUSIONS

A more disordered metabolism structure is found in TRD than in DN-MDD and HCs. Future investigations should prioritize the comprehensive analysis of potential roles played by these differential metabolites and disturbances in polyamine pathways in the pathophysiology of TRD and depression.