Expression of the vesicular GABA transporter within neuromedin S+ neurons sustains behavioral circadian rhythms.

The suprachiasmatic nucleus (SCN) of the hypothalamus is the site of a central circadian clock that orchestrates overt rhythms of physiology and behavior. Circadian timekeeping requires intercellular communication among SCN neurons, and multiple signaling pathways contribute to SCN network coupling. Gamma-aminobutyric acid (GABA) is produced by virtually all SCN neurons, and previous work demonstrates that this transmitter regulates coupling in the adult SCN but is not essential for the nucleus to sustain overt circadian rhythms. Here, we show that the deletion of the gene that codes for the GABA vesicular transporter Vgat from neuromedin-S (NMS)+ neurons-a subset of neurons critical for SCN function-causes arrhythmia of locomotor activity and sleep. Further, NMS-Vgat deletion impairs intrinsic clock gene rhythms in SCN explants cultured ex vivo. Although vasoactive intestinal polypeptide (VIP) is critical for SCN function, Vgat deletion from VIP-expressing neurons did not lead to circadian arrhythmia in locomotor activity rhythms. Likewise, adult SCN-specific deletion of Vgat led to mild impairment of behavioral rhythms. Our results suggest that while the removal of GABA release from the adult SCN does not affect the pacemaker's ability to sustain overt circadian rhythms, its removal from a critical subset of neurons within the SCN throughout development removes the nucleus ability to sustain circadian rhythms. Our findings support a model in which SCN GABA release is critical for the developmental establishment of intercellular network properties that define the SCN as a central pacemaker.

A guide to the BRAIN Initiative Cell Census Network data ecosystem.

Characterizing cellular diversity at different levels of biological organization and across data modalities is a prerequisite to understanding the function of cell types in the brain. Classification of neurons is also essential to manipulate cell types in controlled ways and to understand their variation and vulnerability in brain disorders. The BRAIN Initiative Cell Census Network (BICCN) is an integrated network of data-generating centers, data archives, and data standards developers, with the goal of systematic multimodal brain cell type profiling and characterization. Emphasis of the BICCN is on the whole mouse brain with demonstration of prototype feasibility for human and nonhuman primate (NHP) brains. Here, we provide a guide to the cellular and spatial approaches employed by the BICCN, and to accessing and using these data and extensive resources, including the BRAIN Cell Data Center (BCDC), which serves to manage and integrate data across the ecosystem. We illustrate the power of the BICCN data ecosystem through vignettes highlighting several BICCN analysis and visualization tools. Finally, we present emerging standards that have been developed or adopted toward Findable, Accessible, Interoperable, and Reusable (FAIR) neuroscience. The combined BICCN ecosystem provides a comprehensive resource for the exploration and analysis of cell types in the brain.

Microglia specific deletion of miR-155 in Alzheimer's disease mouse models reduces amyloid-ß pathology but causes hyperexcitability and seizures.

Alzheimer's Disease (AD) is characterized by the accumulation of extracellular amyloid-ß (Aß) as well as CNS and systemic inflammation. Microglia, the myeloid cells resident in the CNS, use microRNAs to rapidly respond to inflammatory signals. MicroRNAs (miRNAs) modulate inflammatory responses in microglia, and miRNA profiles are altered in Alzheimer's disease (AD) patients. Expression of the pro-inflammatory miRNA, miR-155, is increased in the AD brain. However, the role of miR-155 in AD pathogenesis is not well-understood. We hypothesized that miR-155 participates in AD pathophysiology by regulating microglia internalization and degradation of Aß. We used CX3CR1CreER/+ to drive-inducible, microglia-specific deletion of floxed miR-155 alleles in two AD mouse models. Microglia-specific inducible deletion of miR-155 in microglia increased anti-inflammatory gene expression while reducing insoluble Aß1-42 and plaque area. Yet, microglia-specific miR-155 deletion led to early-onset hyperexcitability, recurring spontaneous seizures, and seizure-related mortality. The mechanism behind hyperexcitability involved microglia-mediated synaptic pruning as miR-155 deletion altered microglia internalization of synaptic material. These data identify miR-155 as a novel modulator of microglia Aß internalization and synaptic pruning, influencing synaptic homeostasis in the setting of AD pathology.

Diversity, equity, and inclusion in clinical trials: A practical guide from the perspective of a trial sponsor.

BACKGROUND: Considering diversity, equity, and inclusion (DEI) in clinical trials ensures that data collected for investigational treatments reflect the populations most likely to benefit from those therapies. Resources and recommendations regarding DEI were assembled by the trial sponsor to assist clinical trial development. METHODS: A cross-disciplinary team from the sponsoring organization was assembled to inform trial planning and collate resources that promote DEI throughout the clinical trial life cycle. RESULTS: Representatives from clinical operations, health economic outcomes research, medical affairs, patient advocacy, procurement, and research and development functional groups united together to implement DEI strategies in clinical trials. Planning strategies focus on eligibility, participant/patient engagement, feedback through patient advocacy organizations, and community interactions. Informed site, investigator, and vendor selection at trial startup supports efforts to recruit diverse target trial populations and engage underrepresented businesses; establishing relationships and demographic target-goal tracking should be maintained throughout trial management. Continued communication during trial closeout consolidates learnings and enhances partnerships with trial participants and patient advocacy organizations. The sponsoring organization continuously updates an internal library of resources to facilitate implementation of outlined strategies. CONCLUSIONS: This first iteration of guidance intends to improve the representation of target populations who will ultimately benefit from investigational therapies; to assist sponsor clinical trial teams in developing recruitment and retention plans; and to ensure compliance with federal granting agencies. The sponsoring organization anticipates data from future clinical trials will help characterize the impact of these initiatives to ensure evidence-based practices are used in future clinical trials to enhance DEI.

Brain Data Standards - A method for building data-driven cell-type ontologies.

Large-scale single-cell 'omics profiling is being used to define a complete catalogue of brain cell types, something that traditional methods struggle with due to the diversity and complexity of the brain. But this poses a problem: How do we organise such a catalogue - providing a standard way to refer to the cell types discovered, linking their classification and properties to supporting data? Cell ontologies provide a partial solution to these problems, but no existing ontology schemas support the definition of cell types by direct reference to supporting data, classification of cell types using classifications derived directly from data, or links from cell types to marker sets along with confidence scores. Here we describe a generally applicable schema that solves these problems and its application in a semi-automated pipeline to build a data-linked extension to the Cell Ontology representing cell types in the Primary Motor Cortex of humans, mice and marmosets. The methods and resulting ontology are designed to be scalable and applicable to similar whole-brain atlases currently in preparation.

Emraclidine, a novel positive allosteric modulator of cholinergic M4 receptors, for the treatment of schizophrenia: a two-part, randomised, double-blind, placebo-controlled, phase 1b trial.

BACKGROUND: Emraclidine is a novel, brain-penetrant, highly selective M4 receptor positive allosteric modulator in development for the treatment of schizophrenia. We aimed to evaluate the safety and tolerability of multiple ascending doses of emraclidine in patients with schizophrenia. METHODS: We conducted a two-part, randomised, phase 1b trial in the USA. Eligible participants were aged 18-50 years (part A) or 18-55 years (part B) with a primary diagnosis of schizophrenia per the Diagnostic and Statistical Manual of Mental Disorders 5th edition, as confirmed by the Mini International Neuropsychiatric Interview, and extrapyramidal symptom assessments indicating normal to mild symptoms at screening. Part A evaluated the safety and tolerability of emraclidine in five cohorts of participants with stable schizophrenia who received ascending oral doses of emraclidine 5-40 mg (40 mg was administered as 20 mg twice daily) or placebo at a single US site. Part B was a double-blind, randomised, placebo-controlled study that enrolled adults with acute schizophrenia across five US sites; participants were randomly assigned (1:1:1) to receive emraclidine 30 mg once daily, emraclidine 20 mg twice daily, or placebo for 6 weeks (doses established in part A). The primary endpoint was safety and tolerability, assessed in the safety population (participants who received at least one dose of emraclidine or placebo). This trial is now complete and is registered with ClinicalTrials.gov, NCT04136873. FINDINGS: Between Sept 23, 2019, and Sept 17, 2020, 118 patients were assessed for eligibility and 49 were randomly assigned across five cohorts in part A. 44 participants completed the study, with 36 participants receiving emraclidine and eight receiving placebo. The two highest doses tested were selected for part B. Between Oct 12, 2020, and May 7, 2021, 148 patients were assessed for eligibility and 81 were randomly assigned to emraclidine 30 mg once daily (n=27), emraclidine 20 mg twice daily (n=27), or placebo (n=27) in part B. Incidence of adverse events (14 [52%] of 27 participants in the emraclidine 30 mg once daily group, 15 [56%] of 27 in the emraclidine 20 mg twice daily group, and 14 [52%] of 27 in the placebo group), clinical assessments, and weight changes were similar across groups. The most common adverse event was headache (15 [28%] of 54 participants in the emraclidine groups, seven [26%] of 27 in the placebo group). Modest, transient increases in blood pressure and heart rate in emraclidine groups observed at treatment initiation diminished over time and were not considered clinically meaningful by week 6. INTERPRETATION: These data support further investigation of emraclidine as a once-daily treatment for schizophrenia without need for titration and with a potentially favourable side-effect profile. FUNDING: Cerevel Therapeutics.

Substance use workforce training needs during intersecting epidemics: an analysis of events offered by a regional training center from 2017 to 2020.

BACKGROUND: Intersecting opioid overdose, COVID-19, and systemic racism epidemics have brought unprecedented challenges to the addiction treatment and recovery workforce. From 2017 to 2020, the New England Addiction Technology Transfer Center (ATTC) collected data in real-time on the training and technical assistance (TA) requested and attended by the front-line workforce. This article synthesizes practice-based evidence on the types of TA requests, topics of TA, attendance numbers, and socio-demographics of TA attendees over a 3-year period spanning an unprecedented public health syndemic. METHODS: We assessed TA events hosted by the New England ATTC using SAMHSA's Performance Accountability and Reporting System post-event survey data from 2017 to 2020. Events were coded by common themes to identify the most frequently requested training types/topics and most frequently attended training events. We also evaluated change in training topics and attendee demographics over the three-year timeline. RESULTS: A total of 258 ATTC events reaching 10,143 participants were analyzed. The number of TA events and attendance numbers surged in the 2019-2020 fiscal year as TA events shifted to fully virtual during the COVID-19 pandemic. The absolute number of opioid-related events increased, but the relative proportion remained stable over time. The relative proportions of events and attendance rates focused on evidence-based practice and health equity both increased over the 3-year period, with the largest increase after the onset of the pandemic and the murder of George Floyd. As events shifted to virtual, events were attended by providers with a broader range of educational backgrounds. CONCLUSIONS: Results of the current analysis indicate that the demand for TA increased during the pandemic, with a prioritization of TA focused on evidence-based practice and health equity. The practice-based evidence generated from the New England ATTC may help other training and TA centers to anticipate and nimbly respond to the needs of the workforce in the face of the intersecting epidemics.

Sleep timing and the circadian clock in mammals: Past, present and the road ahead.

Nearly all mammals display robust daily rhythms of physiology and behavior. These approximately 24-h cycles, known as circadian rhythms, are driven by a master clock in the suprachiasmatic nucleus (SCN) of the hypothalamus and affect biological processes ranging from metabolism to immune function. Perhaps the most overt output of the circadian clock is the sleep-wake cycle, the integrity of which is critical for health and homeostasis of the organism. In this review, we summarize our current understanding of the circadian regulation of sleep. We discuss the neural circuitry and molecular mechanisms underlying daily sleep timing, and the trajectory of circadian regulation of sleep across development. We conclude by proposing future research priorities for the field that will significantly advance our mechanistic understanding of the circadian regulation of sleep.

Actigraphy in mechanically ventilated pediatric ICU patients: comparison to PSG and evaluation of behavioral circadian rhythmicity.

Sleep disruption is common in pediatric intensive care unit (PICU) patients, but measuring sleep in this population is challenging. We aimed to evaluate the utility of actigraphy for estimating circadian rhythmicity in mechanically ventilated PICU patients and its accuracy for measuring sleep by comparing it to polysomnogram (PSG). We conducted a single-center prospective observational study of children 6 months - 17 years of age receiving mechanical ventilation and standard, protocolized sedation for acute respiratory failure, excluding children with acute or historical neurologic injury. We enrolled 16 children and monitored them with up to 14 days of actigraphy and 24 hours of simultaneous limited (10 channel) PSG. Daily actigraphy-based activity profiles demonstrated that patients had a high level of nighttime activity (30-41% of total activity), suggesting disrupted circadian activity cycles. Among n = 12 patients with sufficient actigraphy and PSG data overlap, actigraphy-based sleep estimation showed poor agreement with PSG-identified sleep states, with good sensitivity (94%) but poor specificity (28%), low accuracy (70%,) and low agreement (Cohen's kappa = 0.2, 95% CI = 0.08-0.31). Using univariate linear regression, we identified that Cornell Assessment of Pediatric Delirium scores were associated with accuracy of actigraphy but that other clinical factors including sedative medication doses, activity levels, and restraint use were not. In this population, actigraphy did not reliably discern between sleep and wake states. However, in select patients, actigraphy was able to distinguish diurnal variation in activity patterns, and therefore may be useful for evaluating patients' response to circadian-oriented interventions.

Substance Use Workforce Training Needs during Intersecting Epidemics: An Analysis of Events Offered by a Regional Training Center from 2017-2020.

Background: Intersecting opioid overdose, COVID-19, and systemic racism epidemics havebrought unprecedented challenges to the addiction treatment and recovery workforce. From 2017-2020, the New England Addiction Technology Transfer Center (ATTC) collected data in real-time on the training and technical assistance (TA) requested and attended by the front-line workforce. This article synthesizes practice-based evidence on the types of TA requests, topics of TA, attendance numbers, and socio-demographics of TA attendees over a 3-year period spanning an unprecedented public health syndemic. Methods: We assessed TA events hosted by the New England ATTC using SAMHSA’s Performance Accountability and Reporting System post-event survey data from 2017-2020. Events were coded by common themes to identify the most frequently requested training types/topics and most frequently attended training events. We also evaluated change in training topics and attendee demographics over the three-year timeline. Results: A total of 258 ATTC events reaching 10,143 participants were analyzed. The number of TA events and attendance numbers surged in the 2019-2020 fiscal year as TA events shifted to fully virtual during the COVID-19 pandemic. The absolute number of opioid-related events increased, but the relative proportion remained stable over time. The relative proportions of events and attendance rates focused on evidence-based practice and health equity both increased over the 3-year period, with the largest increase after the onset of the pandemic and the murder of George Floyd. As events shifted to virtual, events were attended by providers with a broader range of educational backgrounds. Conclusions: Results of the current analysis indicate that the demand for TA increased during the pandemic, with a prioritization of TA focused on evidence-based practice and health equity. The practice-based evidence generated from the New England ATTC may help other training and TA centers to anticipate and nimbly respond to the needs of the workforce in the face of the intersecting epidemics.

Vasopressin Neurons: Master Integrators of Time and Homeostasis.

A recent article by Gizowski and Bourque shows that vasopressinergic (VP) neurons within the suprachiasmatic nucleus (SCN) master circadian clock have the ability of encoding afferent input from osmosensors and generating appropriate homeostatic responses, suggesting that SCN neurons can integrate internal circadian time and acute changes in homeostatic markers.

Circadian regulation of sleep in a pre-clinical model of Dravet syndrome: dynamics of sleep stage and siesta re-entrainment.

STUDY OBJECTIVES: Sleep disturbances are common co-morbidities of epileptic disorders. Dravet syndrome (DS) is an intractable epilepsy accompanied by disturbed sleep. While there is evidence that daily sleep timing is disrupted in DS, the difficulty of chronically recording polysomnographic sleep from patients has left our understanding of the effect of DS on circadian sleep regulation incomplete. We aim to characterize circadian sleep regulation in a mouse model of DS. METHODS: Here we exploit long-term electrocorticographic recordings of sleep in a mouse model of DS in which one copy of the Scn1a gene is deleted. This model both genocopies and phenocopies the disease in humans. We test the hypothesis that the deletion of Scn1a in DS mice is associated with impaired circadian regulation of sleep. RESULTS: We find that DS mice show impairments in circadian sleep regulation, including a fragmented rhythm of non-rapid eye movement (NREM) sleep and an elongated circadian period of sleep. Next, we characterize re-entrainment of sleep stages and siesta following jet lag in the mouse. Strikingly, we find that re-entrainment of sleep following jet lag is normal in DS mice, in contrast to previous demonstrations of slowed re-entrainment of wheel-running activity. Finally, we report that DS mice are more likely to have an absent or altered daily "siesta". CONCLUSIONS: Our findings support the hypothesis that the circadian regulation of sleep is altered in DS and highlight the value of long-term chronic polysomnographic recording in studying the role of the circadian clock on sleep/wake cycles in pre-clinical models of disease.

A Long-Term, Open-Label Study to Evaluate the Safety and Tolerability of Brexpiprazole as Adjunctive Therapy in Adults With Major Depressive Disorder.

BACKGROUND: Long-term treatment is recommended in major depressive disorder (MDD) to prevent relapse and to restore functioning. The aim of this study (Orion; NCT01360866) was to assess the long-term safety, tolerability, and efficacy of open-label treatment with adjunctive brexpiprazole in adult patients with MDD. METHODS: Patients rolled over into this 52-week study (amended to 26 weeks) from 3 randomized, double-blind, placebo-controlled studies. Patients received brexpiprazole 0.5 to 3 mg/d (flexible dose) adjunct to their current antidepressant treatment. The primary outcome variable was the frequency and severity of treatment-emergent adverse events (TEAEs). Efficacy was assessed as a secondary objective using clinical rating scales. RESULTS: A total of 2944 patients were enrolled (1547 for 52 weeks, 1397 for 26 weeks), of whom 1895 (64.4%) completed the study. The TEAEs with incidence of 5% or greater were weight increase (17.7%), somnolence (8.0%), headache (7.2%), akathisia (6.7%), increased appetite (6.3%), insomnia (6.3%), fatigue (6.1%), viral upper respiratory tract infection (5.4%), and anxiety (5.2%). Most TEAEs were mild or moderate in severity. The mean increase in body weight was 2.7 kg to week 26 and 3.2 kg to week 52; 25.8% of patients had a weight increase of 7% or greater at any postbaseline visit. There were no clinically relevant findings related to extrapyramidal symptoms, prolactin, lipids, or glucose. Patients' symptoms and functioning showed continual improvement. CONCLUSIONS: Adjunctive treatment with open-label brexpiprazole 0.5 to 3 mg/d was generally well tolerated for up to 52 weeks in patients with MDD and was associated with continued improvement in efficacy measures and functional outcomes.

Kisspeptin Neurons in the Arcuate Nucleus of the Hypothalamus Orchestrate Circadian Rhythms and Metabolism.

Successful reproduction in female mammals is precisely timed and must be able to withstand the metabolic demand of pregnancy and lactation. We show that kisspeptin-expressing neurons in the arcuate hypothalamus (Kiss1ARH) of female mice control the daily timing of food intake, along with the circadian regulation of locomotor activity, sleep, and core body temperature. Toxin-induced silencing of Kiss1ARH neurons shifts wakefulness and food consumption to the light phase and induces weight gain. Toxin-silenced mice are less physically active and have attenuated temperature rhythms. Because the rhythm of the master clock in the suprachiasmatic nucleus (SCN) appears to be intact, we hypothesize that Kiss1ARH neurons signal to neurons downstream of the master clock to modulate the output of the SCN. We conclude that, in addition to their well-established role in regulating fertility, Kiss1ARH neurons are a critical component of the hypothalamic circadian oscillator network that times overt rhythms of physiology and behavior.

The safety and tolerability of aripiprazole once-monthly as maintenance treatment for bipolar I disorder: A double-blind, placebo-controlled, randomized withdrawal study.

BACKGROUND: Aripiprazole once-monthly 400 mg (AOM 400), an atypical long-acting injectable antipsychotic, has demonstrated efficacy and safety in maintenance treatment of bipolar I disorder (BP-I). We further assess safety and tolerability and characterize adverse events (AEs) across the duration of aripiprazole exposure. METHODS: Patients with BP-I were stabilized on oral aripiprazole (2-8 weeks), AOM 400 (12-28 weeks), followed by 1:1 randomization of patients meeting stability criteria to a 52-week, double-blind, placebo-controlled withdrawal phase. Treatment-emergent AEs (TEAEs) were collected across study phases. AEs were counted in a phase if they were drug-related and continued from the baseline of that phase. A separate analysis on new-onset akathisia was conducted. RESULTS: Among TEAEs occurring in ≥10% of patients during all study phases were akathisia (23.3%) and weight increased (10.6%). Median time to akathisia onset was 20 days after starting oral aripiprazole; median duration was 29 days for the first occurrence; 21/168 patients (12.5%) reporting akathisia experienced >1 episode. Episodes of new-onset akathisia decreased over time, with few events reported in the randomized phase. Weight gain was minimal with oral aripiprazole, generally starting within 3 months after the first AOM 400 injection, and appearing to plateau at 36 weeks. The mean weight gain within any study phase was ≤1.0 kg. Potentially clinically significant changes in metabolic parameters were uncommon. LIMITATIONS: Patients on placebo had AOM 400 exposure before randomization. CONCLUSION: These findings suggest that AEs with AOM 400 treatment were time-limited and support AOM 400 as a well-tolerated maintenance treatment of BP-I.

A Randomized, Placebo-Controlled Study of the Efficacy and Safety of Fixed-Dose Brexpiprazole 2 mg/d as Adjunctive Treatment of Adults With Major Depressive Disorder.

OBJECTIVE: To assess the efficacy, safety, and tolerability of brexpiprazole as adjunct to antidepressant treatment (ADT) in adults with major depressive disorder (MDD) and inadequate response to ADTs. METHODS: Outpatients with inadequate response to 1-3 ADTs during their current depressive episode (DSM-IV-TR criteria) were administered prospective, open-label ADT. Those patients with inadequate response to prospective ADT were randomized to double-blind, adjunctive brexpiprazole 2 mg/d or placebo. The primary efficacy end point was the change from baseline (randomization) to week 6 in Montgomery-Åsberg Depression Rating Scale (MADRS) total score. Key secondary efficacy end points were the change in Sheehan Disability Scale (SDS) mean score for all patients and the change in MADRS total score for subgroups with minimal response to prospective ADT and DSM-5-defined anxious distress. The study was conducted from July 2014 to May 2016. RESULTS: Adjunctive brexpiprazole (n = 191) improved MADRS total score from baseline to week 6 versus placebo (n = 202; least squares mean difference [95% confidence limits]: -2.30 [-3.97, -0.62]; P = .0074). There was no separation between groups for the SDS mean score (-0.22 [-0.66, 0.23]; P = .33). Adjunctive brexpiprazole also improved MADRS total score versus placebo in the subgroups with minimal response to prospective ADT (-2.25 [-4.23, -0.27]; P = .026) and anxious distress (-2.98 [-5.24, -0.72]; P = .0099). Treatment with adjunctive brexpiprazole was well tolerated with no unexpected side effects. CONCLUSIONS: This study adds to the substantial body of evidence for the efficacy and tolerability of brexpiprazole as adjunctive treatment in patients with MDD and inadequate response to ADTs. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02196506; EudraCT number: 2014-000062-22​​​.

Efficacy and safety of flexibly dosed brexpiprazole for the adjunctive treatment of major depressive disorder: a randomized, active-referenced, placebo-controlled study.

OBJECTIVE: To assess the efficacy, safety, and tolerability of brexpiprazole as adjunctive treatment in adults with major depressive disorder (MDD) and an inadequate response to prior antidepressant treatment (ADT). METHODS: Patients with a current major depressive episode after prior treatment with 1-3 ADTs entered an 8- or 10-week prospective treatment phase in which they received double-blind placebo adjunct to open-label ADT. Inadequate responders were randomized (2:2:1) to brexpiprazole 2-3 mg/day, placebo, or quetiapine extended-release (XR) 150-300 mg/day, adjunct to the same ADT, for 6 weeks. The primary efficacy endpoint was the change from baseline (randomization) to week 6 in Montgomery-Åsberg Depression Rating Scale (MADRS) total score. The key secondary efficacy endpoint was the change in Sheehan Disability Scale (SDS) mean score. RESULTS: Adjunctive brexpiprazole showed a greater improvement in MADRS total score than adjunctive placebo (least squares mean difference [95% confidence interval] = -1.48 [-2.56, -0.39]; p = .0078), whereas adjunctive quetiapine XR did not separate from placebo (-0.30 [-1.63, 1.04]; p = .66). Adjunctive brexpiprazole failed to separate from placebo on the SDS mean score (-0.23 [-0.52, 0.07]; p = .13), but did improve functioning on two of the three SDS items (family life and social life). The most frequent treatment-emergent adverse events in patients receiving brexpiprazole were akathisia (6.1%), somnolence (5.6%), and headache (5.6%). CONCLUSIONS: Adjunctive brexpiprazole 2-3 mg/day improved symptoms of depression compared with adjunctive placebo in patients with MDD and an inadequate response to ADTs, and was well tolerated with no unexpected side effects.