Ketamine: Mechanisms and Relevance to Treatment of Depression.

Major depressive disorder (MDD) is a leading cause of suicide in the world. Monoamine-based antidepressant drugs are a primary line of treatment for this mental disorder, although the delayed response and incomplete efficacy in some patients highlight the need for improved therapeutic approaches. Over the past two decades, ketamine has shown rapid onset with sustained (up to several days) antidepressant effects in patients whose MDD has not responded to conventional antidepressant drugs. Recent preclinical studies have started to elucidate the underlying mechanisms of ketamine's antidepressant properties. Herein, we describe and compare recent clinical and preclinical findings to provide a broad perspective of the relevant mechanisms for the antidepressant action of ketamine.

Neuroplasticity of the left dorsolateral prefrontal cortex in patients with treatment-resistant depression as indexed with paired associative stimulation: a TMS-EEG study.

Major depressive disorder affects over 300 million people globally, with approximately 30% experiencing treatment-resistant depression (TRD). Given that impaired neuroplasticity underlies depression, the present study focused on neuroplasticity in the dorsolateral prefrontal cortex (DLPFC). Here, we aimed to investigate the differences in neuroplasticity between 60 individuals with TRD and 30 age- and sex-matched healthy controls (HCs). To induce neuroplasticity, participants underwent a paired associative stimulation (PAS) paradigm involving peripheral median nerve stimulation and transcranial magnetic stimulation (TMS) targeting the left DLPFC. Neuroplasticity was assessed by using measurements combining TMS with EEG before and after PAS. Both groups exhibited significant increases in the early component of TMS-evoked potentials (TEP) after PAS (P < 0.05, paired t-tests with the bootstrapping method). However, the HC group demonstrated a greater increase in TEPs than the TRD group (P = 0.045, paired t-tests). Additionally, event-related spectral perturbation analysis highlighted that the gamma power significantly increased after PAS in the HC group, whereas it was decreased in the TRD group (P < 0.05, paired t-tests with the bootstrapping method). This gamma power modulation revealed a significant group difference (P = 0.006, paired t-tests), indicating an inverse relationship for gamma power modulation. Our findings underscore the impaired neuroplasticity of the DLPFC in individuals with TRD.

Elevated serum IGFBP-1 levels correlate with cognitive deficits in treatment-resistant and chronic medicated schizophrenia patients.

BACKGROUND: Schizophrenia is a debilitating psychiatric disorder with diverse cognitive impairments. Insulin-like growth factor binding protein 1 (IGFBP-1), a ubiquitous negative regulator of IGF signaling, crosses the blood-brain barrier after peripheral synthesis. Given the crucial role of IGF signaling in cognitive function, we reasoned that altered serum IGFBP-1 concentrations might be associated with cognitive impairments in schizophrenia. To test this hypothesis, we examined the relationship between serum IGFBP-1 levels and cognitive performance in both medicated and treatment-resistant schizophrenia (TRS) patients. METHODS: Serum IGFBP-1 was measured in 31 TRS patients, 49 chronic medicated schizophrenia (CMS) patients, and 53 healthy controls. Clinical symptom severity was evaluated using the Positive and Negative Syndrome Scale (PANSS) and cognitive functions using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). RESULTS: Both TRS and CMS patients exhibited cognitive deficits compared to healthy controls (p < 0.05). Serum IGFBP-1 concentration differed significantly among groups (F=36.805, p < 0.001) and post hoc tests demonstrated significantly higher concentrations in both schizophrenia groups compared to controls (p < 0.001). Further, serum IGFBP-1 concentration was higher in the TRS group than the CMS group (p = 0.048). Correlation analysis identified a significant relationship between serum IGFBP-1 and attention in the TRS group (r = 0.411, p = 0.021), immediate memory in the CMS group (r = -0.417, p = 0.003), and RBANS total score in the CMS group (r = -0.368, p = 0.009). Multiple regression analysis adjusting for confounding factors revealed that serum IGFBP-1 was independently associated with attention in TRS patients (p = 0.016, 95 %CI. 0.002-0.015) and immediate memory in CMS patients (p = 0.022, 95 %CI-0.012 to -0.001). CONCLUSIONS: Elevated serum IGFBP-1 concentration may serve as a predictive biomarker for distinct cognitive deficits in TRS and CMS patients. Further investigations are warranted.

The role of psychosis and clozapine load in excessive checking in treatment-resistant schizophrenia: longitudinal observational study.

BACKGROUND: A significant proportion of people with clozapine-treated schizophrenia develop 'checking' compulsions, a phenomenon yet to be understood. AIMS: To use habit formation models developed in cognitive neuroscience to investigate the dynamic interplay between psychosis, clozapine dose and obsessive-compulsive symptoms (OCS). METHOD: Using the anonymised electronic records of a cohort of clozapine-treated patients, including longitudinal assessments of OCS and psychosis, we performed longitudinal multi-level mediation and multi-level moderation analyses to explore associations of psychosis with obsessiveness and excessive checking. Classic bivariate correlation tests were used to assess clozapine load and checking compulsions. The influence of specific genetic variants was tested in a subsample. RESULTS: A total of 196 clozapine-treated individuals and 459 face-to-face assessments were included. We found significant OCS to be common (37.9%), with checking being the most prevalent symptom. In mediation models, psychosis severity mediated checking behaviour indirectly by inducing obsessions (r = 0.07, 95% CI 0.04-0.09; P < 0.001). No direct effect of psychosis on checking was identified (r = -0.28, 95% CI -0.09 to 0.03; P = 0.340). After psychosis remission (n = 65), checking compulsions correlated with both clozapine plasma levels (r = 0.35; P = 0.004) and dose (r = 0.38; P = 0.002). None of the glutamatergic and serotonergic genetic variants were found to moderate the effect of psychosis on obsession and compulsion (SLC6A4, SLC1A1 and HTR2C) survived the multiple comparisons correction. CONCLUSIONS: We elucidated different phases of the complex interplay of psychosis and compulsions, which may inform clinicians' therapeutic decisions.

Development and initial evaluation of a clinical prediction model for risk of treatment resistance in first-episode psychosis: Schizophrenia Prediction of Resistance to Treatment (SPIRIT).

BACKGROUND: A clinical tool to estimate the risk of treatment-resistant schizophrenia (TRS) in people with first-episode psychosis (FEP) would inform early detection of TRS and overcome the delay of up to 5 years in starting TRS medication. AIMS: To develop and evaluate a model that could predict the risk of TRS in routine clinical practice. METHOD: We used data from two UK-based FEP cohorts (GAP and AESOP-10) to develop and internally validate a prognostic model that supports identification of patients at high-risk of TRS soon after FEP diagnosis. Using sociodemographic and clinical predictors, a model for predicting risk of TRS was developed based on penalised logistic regression, with missing data handled using multiple imputation. Internal validation was undertaken via bootstrapping, obtaining optimism-adjusted estimates of the model's performance. Interviews and focus groups with clinicians were conducted to establish clinically relevant risk thresholds and understand the acceptability and perceived utility of the model. RESULTS: We included seven factors in the prediction model that are predominantly assessed in clinical practice in patients with FEP. The model predicted treatment resistance among the 1081 patients with reasonable accuracy; the model's C-statistic was 0.727 (95% CI 0.723-0.732) prior to shrinkage and 0.687 after adjustment for optimism. Calibration was good (expected/observed ratio: 0.999; calibration-in-the-large: 0.000584) after adjustment for optimism. CONCLUSIONS: We developed and internally validated a prediction model with reasonably good predictive metrics. Clinicians, patients and carers were involved in the development process. External validation of the tool is needed followed by co-design methodology to support implementation in early intervention services.

Neural responses to facial emotions and subsequent clinical outcomes in difficult-to-treat depression.

BACKGROUND: Amygdala and dorsal anterior cingulate cortex responses to facial emotions have shown promise in predicting treatment response in medication-free major depressive disorder (MDD). Here, we examined their role in the pathophysiology of clinical outcomes in more chronic, difficult-to-treat forms of MDD. METHODS: Forty-five people with current MDD who had not responded to ⩾2 serotonergic antidepressants (n = 42, meeting pre-defined fMRI minimum quality thresholds) were enrolled and followed up over four months of standard primary care. Prior to medication review, subliminal facial emotion fMRI was used to extract blood-oxygen level-dependent effects for sad v. happy faces from two pre-registered a priori defined regions: bilateral amygdala and dorsal/pregenual anterior cingulate cortex. Clinical outcome was the percentage change on the self-reported Quick Inventory of Depressive Symptomatology (16-item). RESULTS: We corroborated our pre-registered hypothesis (NCT04342299) that lower bilateral amygdala activation for sad v. happy faces predicted favorable clinical outcomes (rs[38] = 0.40, p = 0.01). In contrast, there was no effect for dorsal/pregenual anterior cingulate cortex activation (rs[38] = 0.18, p = 0.29), nor when using voxel-based whole-brain analyses (voxel-based Family-Wise Error-corrected p < 0.05). Predictive effects were mainly driven by the right amygdala whose response to happy faces was reduced in patients with higher anxiety levels. CONCLUSIONS: We confirmed the prediction that a lower amygdala response to negative v. positive facial expressions might be an adaptive neural signature, which predicts subsequent symptom improvement also in difficult-to-treat MDD. Anxiety reduced adaptive amygdala responses.

Effect of next-step antidepressant treatment on suicidal ideation: findings from the VAST-D trial.

BACKGROUND: Major depressive disorder (MDD) contributes to suicide risk. Treating MDD effectively is considered a key suicide prevention intervention. Yet many patients with MDD do not respond to their initial medication and require a 'next-step'. The relationship between next-step treatments and suicidal thoughts and behaviors is uncharted. METHOD: The VA Augmentation and Switching Treatments for Depression trial randomized 1522 participants to one of three next-step treatments: Switching to Bupropion, combining with Bupropion, and augmenting with Aripiprazole. In this secondary analysis, features associated with lifetime suicidal ideation (SI) and attempts (SA) at baseline and current SI during treatment were explored. RESULTS: Compared to those with SI only, those with lifetime SI + SA were more likely to be female, divorced, or separated, unemployed; and to have experienced more childhood adversity. They had a more severe depressive episode and were more likely to respond to 'next-step' treatment. The prevalence of SI decreased from 46.5% (694/1492) at baseline to 21.1% (315/1492) at end-of-treatment. SI during treatment was associated with baseline SI; low positive mental health, more anxiety, greater severity and longer duration of current MDD episode; being male and White; and treatment with S-BUP or C-BUP as compared to A-ARI. CONCLUSION: SI declines for most patients during next-step medication treatments. But about 1 in 5 experienced emergent or worsening SI during treatment, so vigilance for suicide risk through the entire 12-week acute treatment period is necessary. Treatment selection may affect the risk of SI.

Utilizing plasma drug levels and genetic testing to achieve optimal treatment response in a patient with treatment-resistant schizoaffective disorder.

We report the case of a Chinese male with schizoaffective disorder, an active smoker and a nonresponder to clozapine (600 mg daily). Therapeutic clozapine monitoring was analyzed, revealing a low concentration-dose ratio. A pharmacogenetic test showed that the patient had the CYP1A2*1F/*1F genotype, indicating an ultra-rapid clozapine metabolizer. In combination with fluvoxamine, a CYP1A2 enzyme inhibitor, clozapine plasma concentrations approached the reference range and achieved clinical improvement. This case demonstrates how pharmacogenetics can help understand the value of therapeutic drug monitoring to enhance the treatment of refractory schizoaffective disorder.

Metabolomic biomarkers for (R, S)-ketamine and (S)-ketamine in treatment-resistant depression and healthy controls: A systematic review.

BACKGROUND: Ketamine is increasingly used for treatment-resistant depression (TRD) while its mechanism of action is still being investigated. In this systematic review, we appraise the current evidence of metabolomic biomarkers for racemic ketamine and esketamine in patients with TRD and healthy controls (HCs). METHODS: A comprehensive search of several databases (Ovid MEDLINE®, Embase, and Epub Ahead of Print) was performed from each database's inception to June 29, 2022, in any language, was conducted. We included studies wherein the metabolomic biomarkers for racemic ketamine or esketamine were investigated in TRD or HCs. Our main outcomes were to examine changes in metabolites among patients treated with ketamine/esketamine and explore the association with response to ketamine/esketamine. RESULTS: A total of 1859 abstracts were screened of which 11 were included for full-text review. Of these, a total of five articles were included (N = 147), including three RCTs (n = 129) and two open-label trials (n = 18). All studies used racemic ketamine; one study additionally used esketamine. The included studies evaluated patients with treatment-resistant bipolar depression (n = 22), unipolar depression (n = 91), and HCs (n = 34). The included studies reported alteration in several metabolites including acylcarnitines, lipids, kynurenine (KYN), and arginine with ketamine in TRD. Studies suggest the involvement of energy metabolism, KYN, and arginine pathways. In HCs, acetylcarnitine decreased post-infusion, whereas inconsistent findings were observed after the ketamine infusion in TRD patients. CONCLUSIONS: This systematic review provides preliminary evidence that ketamine may cause changes in several important pathways involved in energy metabolism and inflammation. Larger and more rigorous studies are needed.

Anhedonia in bipolar depression treated with ketamine.

BACKGROUND: Bipolar depression is the major cause of morbidity in patients with bipolar disorder. It affects psychosocial functioning and markedly impairs occupational productivity. Anhedonia is one of the most debilitating symptoms of depression contributing to treatment resistance. It correlates with suicidality, low quality of life, social withdrawal, and poor treatment response. Currently, there is no approved treatment specifically targeting anhedonia. Emerging evidence suggests that ketamine possesses anti-anhedonic properties in individuals with depression. OBJECTIVES: The aim of this naturalistic open-label study was to investigate the effect of add-on ketamine treatment on anhedonia in treatment resistant bipolar depression. METHODS: Our main interest was the change in patient-reported (Snaith-Hamilton Pleasure Scale) and rater-based anhedonia measure (Montgomery-Åsberg Depression Rating Scale-anhedonia subscale). The secondary aim was to analyze the score change in three Inventory of Depressive Symptomatology-Self Report (IDS-SR) domains: mood/cognition, anxiety/somatic, and sleep. Patients underwent assessments at several time points, including baseline, after the third, fifth, and seventh ketamine infusions. Additionally, a follow-up assessment was conducted 1 week following the final ketamine administration. RESULTS: We found improvement in anhedonia symptoms according to both patient-reported and rater-based measures. The improvement in IDS-SR domains was most prominent in anxiety/somatic factor and mood/cognition factor, improvement in sleep factor was not observed. No serious adverse events occurred. CONCLUSION: Add-on ketamine seems to be a good choice for the treatment of anhedonia in treatment resistant bipolar depression. It also showed a good effect in reducing symptoms of anxiety in this group of patients. Considering unmet needs and the detrimental effect of anhedonia and anxiety, more studies are needed on ketamine treatment in resistant bipolar depression.

miRNAs in treatment-resistant depression: a systematic review.

BACKGROUND: Treatment-resistant depression (TRD) is a condition in a subset of depressed patients characterized by resistance to antidepressant medications. The global prevalence of TRD has been steadily increasing, yet significant advancements in its diagnosis and treatment remain elusive despite extensive research efforts. The precise underlying pathogenic mechanisms are still not fully understood. Epigenetic mechanisms play a vital role in a wide range of diseases. In recent years, investigators have increasingly focused on the regulatory roles of miRNAs in the onset and progression of TRD. miRNAs are a class of noncoding RNA molecules that regulate the translation and degradation of their target mRNAs via interaction, making the exploration of their functions in TRD essential for elucidating their pathogenic mechanisms. METHODS AND RESULTS: A systematic search was conducted in four databases, namely PubMed, Web of Science, Cochrane Library, and Embase, focusing on studies related to treatment-resistant depression and miRNAs. The search was performed using terms individually or in combination, such as "treatment-resistant depression," "medication-resistant depression," and "miRNAs." The selected articles were reviewed and collated, covering the time period from the inception of each database to the end of February 2024. We found that miRNAs play a crucial role in the pathophysiology of TRD through three main aspects: 1) involvement in miRNA-mediated inflammatory responses (including miR-155, miR-345-5p, miR-146a, and miR-146a-5p); 2) influence on 5-HT transport processes (including miR-674,miR-708, and miR-133a); and 3) regulation of synaptic plasticity (including has-miR-335-5p,has-miR- 1292-3p, let-7b, and let-7c). Investigating the differential expression and interactions of these miRNAs could contribute to a deeper understanding of the molecular mechanisms underlying TRD. CONCLUSIONS: miRNAs might play a pivotal role in the pathogenesis of TRD. Gaining a deeper understanding of the roles and interrelations of miRNAs in TRD will contribute to elucidating disease pathogenesis and potentially provide avenues for the development of novel diagnostic and therapeutic strategies.

Recent Advances in the Treatment of Treatment-Resistant Depression: A Narrative Review of Literature Published from 2018 to 2023.

PURPOSE OF REVIEW: We review recent advances in the treatment of treatment-resistant depression (TRD), a disorder with very limited treatment options until recently. We examine advances in psychotherapeutic, psychopharmacologic, and interventional psychiatry approaches to treatment of TRD. We also highlight various definitions of TRD in recent scientific literature. RECENT FINDINGS: Recent evidence suggests some forms of psychotherapy can be effective as adjunctive treatments for TRD, but not as monotherapies alone. Little recent evidence supports the use of adjunctive non-antidepressant pharmacotherapies such as buprenorphine and antipsychotics for the treatment of TRD; side effects and increased medication discontinuation rates may outweigh the benefits of these adjunctive pharmacotherapies. Finally, a wealth of recent evidence supports the use of interventional approaches such as electroconvulsive therapy, ketamine/esketamine, and transcranial magnetic stimulation for TRD. Recent advances in our understanding of how to treat TRD have largely expanded our knowledge of best practices in, and efficacy of, interventional psychiatric approaches. Recent research has used a variety of TRD definitions for study inclusion criteria; research on TRD should adhere to inclusion criteria based on internationally defined guidelines for more meaningfully generalizable results.

Psychosocial outcomes six months after epilepsy surgery: A perspective on coping strategies.

OBJECTIVE: Epilepsy negatively affects the social functioning of patients. Epilepsy surgery is a treatment with superior rates of seizure freedom. The psychosocial outcomes after epilepsy surgery depend on several factors, including the patient's coping style. It is important to identify the patients who are at risk of experiencing psychosocial difficulties after epilepsy surgery and consult them for psychiatric interventions. This study aimed to assess changes in social adaptation, felt stigma, self-esteem, and self-efficacy after epilepsy surgery, and the effect of coping strategies, sociodemographic and epilepsy-related variables, and post-surgical seizure outcomes on these results. METHODS: Thirty adult patients with temporal lobe epilepsy who were candidates for surgery were included in the study (mean age: 33.07, mean seizure onset age: 17.2, mean duration of epilepsy: 15.8). The patients were assessed before and 6 months after epilepsy surgery using the Epilepsy Self-Efficacy Scale, Social Adaptation Self-Evaluation Scale, Rosenberg Self-Esteem Scale, Felt Stigma Scale, and Coping Orientation to Problems Experienced Inventory. RESULTS: The patients' self-efficacy levels were increased after surgery (p = 0.005). Postsurgical social adaptation levels were associated with higher positive reinterpretation and growth, active coping, and planning (p = 0.016, p = 0.005, p = 0.002, respectively). Postsurgical self-efficacy levels were positively associated with active coping and planning (p = 0.003, p = 0.035, respectively). Postsurgical self-esteem (p = 0.012, p = 0.049, p = 0.034, respectively) and stigma (p = 0.029, p = 0.014, p = 0.027, respectively) were negatively associated with positive reinterpretation and growth, active coping, and planning. Furthermore, being employed presurgical period was associated with better postsurgical social adaptation (p = 0.004). CONCLUSIONS: The psychosocial outcomes after epilepsy surgery depend not only on seizure outcomes. Understanding the factors beyond seizure freedom, allows healthcare professionals to have a pivotal role in exploring and managing patients' expectations, fostering a more comprehensive and realistic dialogue about potential outcomes. Considering employed patients had better psychosocial outcomes, we suggest patients' families, healthcare professionals, and epilepsy support organizations should work collaboratively to support people with epilepsy in terms of providing job opportunities.

The longitudinal effects of cannabidiol on brain temperature in patients with treatment-resistant epilepsy.

Neuroinflammation (NI) is a key pathophysiological contributor to treatment-resistant epilepsy (TRE) that remains challenging to observe in vivo. Magnetic resonance spectroscopic imaging and thermometry (MRSI-t) is an emerging technique that can be used to non-invasively map brain temperature, whereby brain temperature elevations serve as a surrogate for the cellular and biochemical processes associated with NI. In a previous multimodal imaging study of focal epilepsy patients, we observed MRSI-t-based brain temperature elevations ipsilateral to the seizure onset zone (SOZ) that were concordant with evidence of edema (Sharma et al., 2023). Despite its potential as tool, it is unclear if MRSI-t can monitor changes in brain temperature in response to treatment. We imaged 25 participants approximately 12-weeks apart. Eight patients with TRE were imaged before receiving highly-purified pharmaceutical grade cannabidiol (CBD; pre-CBD) and after 12-weeks of CBD (on-CBD) therapy. Seventeen healthy controls (HCs) were also imaged twice. Repeated measures t-tests computed changes in TRE patients' seizure symptoms, mood, and brain temperature within their respective SOZs. Repeated measures ANOVAs tested Group*Time changes in imaging data. Participants with TRE had abnormally high peak brain temperatures within their SOZs that decreased after CBD initiation (p < 0.0001). Seizure severity scores also improved after CBD initiation (p < 0.001). These findings provide insights into the possible neural effects of CBD, and further demonstrate MRSI-t's potential as a tool for delineating SOZ. Further investigations into MRSI-t as a longitudinal measure of therapy-induced changes in NI are warranted.

Side effects of clozapine in older adults with treatment-resistant schizophrenia compared to younger adults.

OBJECTIVES: To study the differences in side effects of clozapine between older adults aged ≥55 years and younger adults aged 18-55 years with treatment-resistant schizophrenia. METHODS: A retrospective cohort study in a large mental health institute in the Netherlands. All patients diagnosed with treatment-resistant schizophrenia who started with clozapine between 2011 and 2020 (N = 284) were included. We compared the number and type of side effects reported in the electronic patient files as well as the number of treatment discontinuations and the time until discontinuation, both due to side effects, of older adults versus younger adults. RESULTS: In the younger age group (N = 183), the number of reported side effects was significantly higher in the first 3 months of treatment (Mann-Whitney U = 7341.5, p = 0.004) and after those 3 months (Mann-Whitney U = 5668.5, p < 0.001) compared with the number reported in the older age group (N = 101). Sedation, hypersalivation, dizziness, tachycardia, heartburn, nausea, weight gain, and constipation were reported significantly more often in the younger age group, and only extrapyramidal symptoms were reported significantly more often in the older age group. There was no significant difference in the number of treatment discontinuations due to side effects (23% vs. 21.8%, Chi-2 = 0.051, df = 1, p = 0.821) and time until discontinuation due to side effects (b = 0.091, SE = 0.335, p = 0.798) between younger and older adults. CONCLUSIONS: Side effects of clozapine were reported significantly less often in older patients compared with younger patients. Older patients did not discontinue treatment due to side effects more often or earlier than younger patients. Older patients with schizophrenia may not be more vulnerable to side effects than younger adults.

Alcohol and substance use in older adults with treatment-resistant depression.

INTRODUCTION: Alcohol and substance use are increasing in older adults, many of whom have depression, and treatment in this context may be more hazardous. We assessed alcohol and other substance use patterns in older adults with treatment-resistant depression (TRD). We examined patient characteristics associated with higher alcohol consumption and examined the moderating effect of alcohol on the association between clinical variables and falls during antidepressant treatment. METHODS: This secondary and exploratory analysis used baseline clinical data and data on falls during treatment from a large randomized antidepressant trial in older adults with TRD (the OPTIMUM trial). Multivariable ordinal logistic regression was used to identify variables associated with higher alcohol use. An interaction model was used to evaluate the moderating effect of alcohol on falls during treatment. RESULTS: Of 687 participants, 51% acknowledged using alcohol: 10% were hazardous drinkers (AUDIT-10 score ≥5) and 41% were low-risk drinkers (score 1-4). Benzodiazepine use was seen in 24% of all participants and in 21% of drinkers. Use of other substances (mostly cannabis) was associated with alcohol consumption: it was seen in 5%, 9%, and 15% of abstainers, low-risk drinkers, and hazardous drinkers, respectively. Unexpectedly, use of other substances predicted increased risk of falls during antidepressant treatment only in abstainers. CONCLUSIONS: One-half of older adults with TRD in this study acknowledged using alcohol. Use of alcohol concurrent with benzodiazepine and other substances was common. Risks-such as falls-of using alcohol and other substances during antidepressant treatment needs further study.

Adjunctive cariprazine for major depressive disorder: a systematic review and meta-analysis.

Converging evidence has suggested that treatment augmentation with a second-generation atypical antipsychotic (SGA) may improve treatment outcomes in major depressive disorder (MDD) patients after an incomplete response to a first-line antidepressant. Cariprazine is a recently approved SGA for MDD augmentation. Herein, we evaluate both continuous (ie, change in depressive symptom severity scores over time) and categorical (ie, remission and response rates) outcomes. Following a full-text review, four randomized controlled trials (RCTs) were included in our meta-analysis, while five studies were included for a qualitative review. Risk ratios (RRs) were calculated for all included randomized controlled studies to determine the relative response and remission rates of cariprazine compared to placebo augmentation. The RR for all-cause dropout was also determined as a proxy for overall acceptability. Two studies found a statistically significant treatment response using cariprazine augmentation. One study observed depressive symptom remission for cariprazine compared to placebo. Our random-effects model revealed moderate antidepressant effects of cariprazine, with a standardized mean difference (SMD) in Montgomery-Åsberg Depression Rating Scale (MADRS) scores of -1.79 (95% CI): -2.89, -0.69). Our pooled response RR and remission RR were calculated as 1.21 (95% CI: 1.05, 1.39, P=0.008) and 0.99 (95% CI: 0.84, 1.17, P=0.91), respectively. The RR for response was statistically significant (P<0.05). However, the RR for remission was not statistically significant. The findings from our meta-analysis include a variable magnitude of effects. Evidence suggests cariprazine may be an effective treatment for MDD; however, further results are needed to clarify this relation.

Real-world case series of maintenance theta burst stimulation therapy following response to acute theta burst stimulation therapy for difficult-to-treat depression.

OBJECTIVE: Treatment and management for difficult-to-treat depression are challenging, especially in a subset of patients who are at high risk for relapse and recurrence. The conditions that represent this subset are recurrent depressive disorder (RDD) and bipolar disorder (BD). In this context, we aimed to examine the effectiveness of maintenance transcranial magnetic stimulation (TMS) on a real-world clinical basis by retrospectively extracting data from the TMS registry data in Tokyo, Japan. METHODS: Data on patients diagnosed with treatment-resistant RDD and BD who received maintenance intermittent theta burst stimulation (iTBS) weekly after successful treatment with acute iTBS between March 2020 and October 2023 were extracted from the registry. RESULTS: All patients (21 cases: 10 cases with RDD and 11 cases with BD) could sustain response, and 19 of them further maintained remission. In this study, maintenance iTBS did not exacerbate depressive symptoms in any of the cases, but may rather have the effect of stabilizing the mental condition and preventing recurrence. CONCLUSIONS: This case series is of great clinical significance because it is the first study to report on the effectiveness of maintenance iTBS for RDD and BD, with a follow-up of more than 2 years. Further validation with a randomized controlled trial design with a larger sample size is warranted.

Effects of esketamine nasal spray on depressive symptom severity in adults with treatment-resistant depression and associations between the Montgomery-Åsberg Depression Rating Scale and the 9-item Patient Health Questionnaire.

OBJECTIVE: To examine the effect of esketamine nasal spray (ESK) plus newly initiated oral antidepressant (OAD) versus OAD plus placebo nasal spray (PBO) on the association between Montgomery-Åsberg Depression Rating Scale (MADRS) and 9-item Patient Health Questionnaire (PHQ-9) scores in adults with treatment-resistant depression (TRD). METHODS: Data from TRANSFORM-1 and TRANSFORM-2 (two similarly designed, randomized, active-controlled TRD studies) and SUSTAIN-1 (relapse prevention study) were analyzed. Group differences for mean changes in PHQ-9 total score from baseline were compared using analysis of covariance. Associations between MADRS and PHQ-9 total scores from TRANSFORM-1/TRANSFORM-2 were assessed using simple parametric, nonparametric, and multiple regression models. RESULTS: In TRANSFORM-1/TRANSFORM-2 (ESK + OAD, n = 343; OAD + PBO, n = 222), baseline PHQ-9 mean scores were 20.4 for ESK + OAD and 20.6 for OAD + PBO (severe depression). At day 28, significant group differences were observed in least squares mean change (SE) in PHQ-9 scores from baseline (-12.8 [0.46] vs -10.3 [0.53], P < .001) and in clinically substantial change in PHQ-9 scores (≥6 points; 77.1% vs 64%, P < .001) in ESK + OAD and OAD + PBO groups, respectively. A nonlinear relationship between MADRS and PHQ-9 was observed; total scores demonstrated increased correlation over time. In SUSTAIN-1, 57.3% of patients receiving ESK + OAD (n = 89) versus 44.2% receiving OAD + PBO (n = 86) retained remission status (PHQ-9 score ≤4) at maintenance treatment end point (P = .044). CONCLUSIONS: In adults with TRD, ESK + OAD significantly improved severity of depressive symptoms, and more patients achieved clinically meaningful changes in depressive symptoms based on PHQ-9, versus OAD + PBO. PHQ-9 outcomes were consistent with those of clinician-rated MADRS. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02417064, NCT02418585, NCT02493868.

Esketamine in depression: putative biomarkers from clinical research.

The discovery of racemic (R, S)-ketamine as a rapid-acting antidepressant and the subsequent FDA approval of its (S)-enantiomer, esketamine, for treatment-resistant depression (TRD) are significant advances in the development of novel neuropsychiatric therapeutics. Esketamine is now recognized as a powerful tool for addressing persistent symptoms of TRD compared to traditional oral antidepressants. However, research on biomarkers associated with antidepressant response to esketamine has remained sparse and, to date, has been largely extrapolated from racemic ketamine studies. Genetic, proteomic, and metabolomic profiles suggest that inflammation and mitochondrial function may play a role in esketamine's antidepressant effects, though these preliminary results require verification. In addition, neuroimaging research has consistently implicated the prefrontal cortex, striatum, and anterior cingulate cortex in esketamine's effects. Esketamine also shows promise in perioperative settings for reducing depression and anxiety, and these effects appear to correlate with increased peripheral biomarkers such as brain-derived neurotrophic factor and serotonin. Further indications are likely to be identified with the continued repurposing of racemic ketamine, providing further opportunity for biomarker study and mechanistic understanding of therapeutic effects. Novel methodologies and well-designed biomarker-focused clinical research trials are needed to more clearly elucidate esketamine's therapeutic actions as well as biologically identify those most likely to benefit from this agent, allowing for the improved personalization of antidepressant treatment.