Current concepts in treating mild cognitive impairment in Parkinson's disease.

Impairment in various aspects of cognition is recognized as an important non-motor symptom of Parkinson's disease (PD). Mild cognitive impairment in PD (PD-MCI) is common in non-demented PD patients and is often associated with severity of motor symptoms, disease duration and increasing age. Further, PD-MCI can have a significant negative effect on performance of daily life activities and may be a harbinger of development of PD dementia. Thus, there is significant interest in developing therapeutic strategies to ameliorate cognitive deficits in PD and improve cognitive functioning of PD patients. However, due to significant questions that remain regarding the pathophysiology of cognitive dysfunction in PD, remediation of cognitive dysfunction in PD has proven difficult. In this paper, we will focus on PD-MCI and will review some of the current therapeutic approaches being taken to try to improve cognitive functioning in patients with PD-MCI.

Investigation of the risk factors of vomiting during linezolid therapy: a retrospective observational study.

PURPOSE: Some clinical studies have reported the occurrence of nausea and vomiting with linezolid (LZD) administration. However, no studies have evaluated nausea and vomiting as primary endpoints. In a previous study, we noted a possible relationship between LZD and vomiting, but risk factors were not identified. Therefore, the aim of the present study was to identify them. METHODS: Patients who received LZD 600 mg twice daily at Hokkaido University Hospital from September 2008 to April 2019 were enrolled in this retrospective observational study. Patient characteristics, concomitant medications, laboratory data, and the occurrence of vomiting were obtained from electronic medical records. Logistic regression analysis was performed to identify risk factors for vomiting, including age, sex, body weight, concomitant medications, and surgeries. RESULTS: A total of 496 patients were included in this study, of which 90 experienced vomiting. By multivariate logistic regression analysis, female sex (adjusted odds ratio [aOR], 2.69; 95% confidence interval [CI], 1.62-4.47), ≥ 10 days of LZD administration (aOR, 2.57; CI, 1.46-4.50), and hyponatraemia (aOR, 2.96; CI, 1.72-5.10) were identified as independent risk factors for vomiting; administration of serotonergic agents (aOR, 0.23; CI, 0.07-0.82) was negatively associated. CONCLUSIONS: This study is the first to successfully identify risk factors for LZD-induced vomiting. Careful monitoring of patients with these risk factors may lead to safer and sustainable LZD administration.

Antidepressant and anxiolytic compounds isolated from Salvia elegans interact with serotonergic drugs.

Salvia elegans belongs to a genus plants with biological activities in central nervous system. In this work, the purpose was to evaluate the anxiolytic and antidepressant effects of fractions and compounds isolated from S. elegans and its interaction with serotoninergic drugs by using behavioral tests in mice. Fractions from aerial parts of S. elegans were obtained by column chromatography, SeF1, SeF2, SeF3, and SeF4. Each of them was administered to 25 mg/k in ICR mice subject to forced swimming test (FST), or elevated plus maze test (EPM), or open field test (OFT). The most active fractions were chemically separated until compounds, which were analyzed as anxiolytic or antidepressant and the coadministration of these treatments with 5-HT1A and 5-HT2 drugs was measured in the different biological tests. All fractions were anxiolytic and antidepressant, oleanolic acid (OA) was found in SeF2, and from SeF3, a mixture of terpenes was found; a GC-MS analysis confirmed the presence of two main compounds: rosifoliol and agaraspirol (TM, mixture of terpenes). TM (doses-response curve, 0.01, 0.1, 0.5, 1.0, and 2.0 mg/kg) and OA (5 mg/kg) were also evaluated demonstrating an antidepressant and anxiolytic effect, respectively. The combination of TM (0.5 mg/kg) with 8-OH (selective 5-HT1A receptor agonist) induced an increment of antidepressant activity, while with the antagonist WAY-100635, the effect diminished. But with DOI (5-HT1c/5-HT2 receptor agonist), there was no change, and with KET (5-HT2 receptor antagonist), the activity was increased. When OA is co-administered with 8-OH or with DOI, the anxiolytic activity of this terpene, diminished; but with the combination with antagonists, the effect of OA shows no change. TM and OA were antidepressant and anxiolytic, respectively, on mice exposed to different tests, and these are able to interact with serotoninergic drugs.

Two randomized, double-blind, placebo-controlled trials and one open-label, long-term trial of brexpiprazole for the acute treatment of bipolar mania.

BACKGROUND: Brexpiprazole is a dopamine/serotonin receptor partial agonist (D2, 5-HT1A) and antagonist (5-HT2A) approved for treatment of schizophrenia and major depressive disorder (adjunct to antidepressants). AIMS: This study aimed to investigate brexpiprazole as monotherapy in acute mania (bipolar I disorder) in two short-term (ST) studies (study 080 and study 081) and one open-label (OL) extension (study 083). METHODS: ST studies were three-week randomized, double-blind, flexible dose (2-4 mg/day), placebo-controlled studies. The primary endpoint was mean change in Young Mania Rating Scale (YMRS) total score from baseline to day 21. The OL study was a 26-week flexible dose (2-4 mg/day) study for patients completing the ST studies. RESULTS: A total of 164 and 158 (study 080) and 170 and 162 (study 081) inpatients with DSM-5 mania with/without mixed features were randomized to placebo or brexpiprazole, respectively. The primary analyses did not show a statistically significant difference between brexpiprazole and placebo: study 080: least squares mean difference (95% confidence limits): 0.14 (-1.74, 2.03), p = 0.8797; study 081: -1.62 (-3.56, 0.32), p = 0.1011. OL study patients (n = 381) demonstrated a gradual improvement in YMRS total score. Akathisia was the only adverse event, with an incidence of ⩾5% with brexpiprazole and more than placebo in the ST studies, or ⩾5% in the OL study. Brexpiprazole was more efficacious in patients with impaired or no insight (predominantly EU patients) than in patients with excellent insight (predominantly US patients). CONCLUSIONS: Further studies are necessary to address the potential efficacy of brexpiprazole in acute mania, which should ensure that the study sample is severe enough (especially with regard to insight), and that the dose/titration schedule is not too modest.

Genetic deletion of Rgs12 in mice affects serotonin transporter expression and function in vivo and ex vivo.

BACKGROUND: Regulator of G protein Signaling (RGS) proteins inhibit G protein-coupled receptor (GPCR) signaling, including the signals that arise from neurotransmitter release. We have shown that RGS12 loss diminishes locomotor responses of C57BL/6J mice to dopamine transporter (DAT)-targeting psychostimulants. This diminution resulted from a brain region-specific upregulation of DAT expression and function in RGS12-null mice. This effect on DAT prompted us to investigate whether the serotonin transporter (SERT) exhibits similar alterations upon RGS12 loss in C57BL/6J mice. AIMS: Does RGS12 loss affect (a) hyperlocomotion to the preferentially SERT-targeting psychostimulant 3,4-methylenedioxymethamphetamine (MDMA), (b) SERT expression and function in relevant brain regions, and/or (c) serotonergically modulated behaviors? METHODS: Open-field and spontaneous home-cage locomotor activities were quantified. 5-HT, 5-HIAA, and SERT levels in brain-region homogenates, as well as SERT expression and function in brain-region tissue preparations, were measured using appropriate biochemical assays. Serotonergically modulated behaviors were assessed using forced swim and tail suspension paradigms, elevated plus and elevated zero maze tests, and social interaction assays. RESULTS: RGS12-null mice displayed no hyperlocomotion to 10 mg/kg MDMA. There were brain region-specific alterations in SERT expression and function associated with RGS12 loss. Drug-naïve RGS12-null mice displayed increases in both anxiety-like and anti-depressive-like behaviors. CONCLUSION: RGS12 is a critical modulator of serotonergic neurotransmission and serotonergically modulated behavior in mice; lack of hyperlocomotion to low dose MDMA in RGS12-null mice is related to an alteration of steady-state SERT expression and 5-HT uptake.

mTOR activation by constitutively active serotonin6 receptors as new paradigm in neuropathic pain and its treatment.

Chronic neuropathic pain is a highly disabling syndrome that is poorly controlled by currently available analgesics. Here, we show that painful symptoms and associated cognitive deficits induced by spinal nerve ligation in the rat are prevented by the administration of serotonin 5-HT6 receptor inverse agonists or by the mTOR inhibitor rapamycin. In contrast, they are not alleviated by the administration of 5-HT6 receptor neutral antagonists. Likewise, activation of mTOR by constitutively active 5-HT6 receptors mediates allodynia in oxaliplatin-induced peripheral neuropathy in rats but not mechanical nociception in healthy rats. Furthermore, both painful and co-morbid cognitive symptoms in neuropathic rats are strongly reduced by intrathecal delivery of a cell-penetrating peptide that disrupts 5-HT6 receptor/mTOR physical interaction. Collectively, these findings demonstrate a deleterious influence of non-physiological mTOR activation by constitutively active spinal 5-HT6 receptors upon painful and cognitive symptoms in neuropathic pains of different etiologies. They suggest that targeting the constitutive activity of 5-HT6 receptors with inverse agonists or disrupting the 5-HT6 receptor/mTOR interaction might be valuable strategies for the alleviation of neuropathic pain and cognitive co-morbidities.

Life-Threatening Serotonin Syndrome Precipitated by Discontinuation of Serotonin-Dopamine Antagonist in the Presence of Serotonergic Agents: A Case Report.

INTRODUCTION: Serotonin syndrome is caused by excessive activation of serotonin (5-hydroxytryptamine [5-HT]) neurotransmission. Although the discontinuation of antipsychotics with 5-HT2 receptor antagonistic characteristics could theoretically result in serotonin syndrome, there have been very few reports on the syndrome thus far. CASE PRESENTATION: A 75-year-old woman with somatoform disorder was transferred to our emergency room because of pyrexia, unconsciousness, and myoclonus with hyperreflexia. She had been taking milnacipran and perospirone for 10 years and had started taking duloxetine 2 months before the event. Thereafter, she suffered diaphoresis, gait disturbance, and tremor. Her psychiatrist advised her to stop taking perospirone, because of suspicion of extrapyramidal symptoms, a day before admission. The clinical diagnosis of serotonin syndrome was made based on her symptoms while using serotonergic agents. Her symptoms were so severe that she was transferred to the intensive care unit, where supportive care was successful. CONCLUSIONS: Discontinuation of antipsychotics that are 5-HT2 receptor antagonists may lead to serotonin syndrome in patients who take serotonergic agents. As extrapyramidal symptoms and serotonin toxicity share some clinical features, detailed drug history and physical examination are necessary for successful treatment.

Current and Future Therapies for Psoriasis with a Focus on Serotonergic Drugs.

Psoriasis is a chronic immune-mediated skin disease, with a pathogenesis resulting from a combination of genetic and environmental factors. The pathogenesis of psoriasis is driven by the interaction between innate and adaptive immune cells and keratinocytes, in a complex process mediated by cytokines and other signaling molecules. This leads to an inflammatory process with increased proliferation of epidermal cells, neo-angiogenesis, and infiltration of white cells in the skin, which cause the characteristic psoriasis plaques. Several studies have suggested that the neurotransmitter serotonin, a key mediator between the skin and the neuroendocrine system, also plays an important role in the pathogenesis of psoriasis. Psoriasis often needs long-term treatment, which can be a burden. Thus, the choice of the treatment is crucial to increase the patients' adherence and quality of life. This review addresses the currently available systemic and topical treatments for psoriasis, used by themselves or combined with phototherapy. It particularly focuses on the importance of advanced drug delivery systems as a way to increase the drug penetration and retention in the skin, while also enhancing its solubility and stability. Finally, we discuss the role of the serotonin system in psoriasis, and summarize what is known about the effects of antidepressants, in particular specific serotonin reuptake inhibitors, on the physical symptoms of this disease.

Neuromodulation Leads to a Burst-Tonic Switch in a Subset of VIP Neurons in Mouse Primary Somatosensory (Barrel) Cortex.

Neocortical GABAergic interneurons expressing vasoactive intestinal polypeptide (VIP) contribute to sensory processing, sensorimotor integration, and behavioral control. In contrast to other major subpopulations of GABAergic interneurons, VIP neurons show a remarkable diversity. Studying morphological and electrophysiological properties of VIP cells, we found a peculiar group of neurons in layer II/III of mouse primary somatosensory (barrel) cortex, which showed a highly dynamic burst firing behavior at resting membrane potential that switched to tonic mode at depolarized membrane potentials. Furthermore, we demonstrate that burst firing depends on T-type calcium channels. The burst-tonic switch could be induced by acetylcholine (ACh) and serotonin. ACh mediated a depolarization via nicotinic receptors whereas serotonin evoked a biphasic depolarization via ionotropic and metabotropic receptors in 48% of the population and a purely monophasic depolarization via metabotropic receptors in the remaining cells. These data disclose an electrophysiologically defined subpopulation of VIP neurons that via neuromodulator-induced changes in firing behavior is likely to regulate the state of cortical circuits in a profound manner.

Determination of flibanserin in the presence of confirmed degradation products by a third derivative emission spectrofluorometric method: Application to pharmaceutical formulation.

Flibanserin is a new drug used for the treatment of hypoactive sexual desire disorder. This work is considered the first study concerning the fluorimetric behaviour of flibanserin and its new florescent degradation products. A fast, cost-effective, stability-indicating spectrofluorometric method was developed and validated for the determination of flibanserin in the presence of oxidative degradation products. Stability studies are performed to predict the behaviour of substances under various harsh conditions. Thus, flibanserin was subjected to degradation using hydrogen peroxide. The stability-indicating method was developed and validated per ICH guidelines; it was linear in the range of 0.1-3 µg/mL. The method was accurate and precise as it showed good recoveries between 98.50 and 100.90% and relative standard deviation less than 2%, respectively, and no significant differences were found after statistical comparison with the in-house HPLC method. In addition, the structures of the oxidative degradation products were confirmed using infrared spectroscopy and mass spectrometry, and the proposed degradation pathway was predicted.

Effects of dopamine and serotonin synthesis inhibitors on the ketamine-, d-amphetamine-, and cocaine-induced locomotor activity of preweanling and adolescent rats: sex differences.

The pattern of ketamine-induced locomotor activity varies substantially across ontogeny and according to sex. Although ketamine is classified as an NMDA channel blocker, it appears to stimulate the locomotor activity of both male and female rats via a monoaminergic mechanism. To more precisely determine the neural mechanisms underlying ketamine's actions, male and female preweanling and adolescent rats were pretreated with vehicle, the dopamine (DA) synthesis inhibitor ∝-methyl-DL-p-tyrosine (AMPT), or the serotonin (5-HT) synthesis inhibitor 4-chloro-DL-phenylalanine methyl ester hydrochloride (PCPA). After completion of the pretreatment regimen, the locomotor activating effects of saline, ketamine, d-amphetamine, and cocaine were assessed during a 2 h test session. In addition, the ability of AMPT and PCPA to reduce dorsal striatal DA and 5-HT content was measured in male and female preweanling, adolescent, and adult rats. Results showed that AMPT and PCPA reduced, but did not fully attenuate, the ketamine-induced locomotor activity of preweanling rats and female adolescent rats. Ketamine (20 and 40 mg/kg) caused a minimal amount of locomotor activity in male adolescent rats, and this effect was not significantly modified by AMPT or PCPA pretreatment. When compared to ketamine, d-amphetamine and cocaine produced different patterns of locomotor activity across ontogeny; moreover, AMPT and PCPA pretreatment affected psychostimulant- and ketamine-induced locomotion differently. When these results are considered together, it appears that both dopaminergic and serotonergic mechanisms mediate the ketamine-induced locomotor activity of preweanling and female adolescent rats. The dichotomous actions of ketamine relative to the psychostimulants in vehicle-, AMPT-, and PCPA-treated rats, suggests that ketamine modulates DA and 5-HT neurotransmission through an indirect mechanism.

Tryptophan alleviates neuroendocrine and behavioral responses to stress in zebrafish.

Stressful experiences are related to the triggering of anxiety and mood disorders. Tryptophan (amino acid precursor of serotonin synthesis) emerges as important treatment of these disorders. Here, we evaluate the effects of pre-treatment with tryptophan (300 mg/L) and fluoxetine (50 µg/L) in response to acute stress in zebrafish. Overall, acute stress decreased the distance traveled, entries and time in top of tank, as well as increased the cortisol levels, demonstrating an anxiogenic behavior. Tryptophan and fluoxetine prevented anxiogenic effects. This study showed the importance of tryptophan and fluoxetine in the regulation of stress and anxiety-like behavior in adult zebrafish. Collectively, our data support tryptophan effects on stress responses in zebrafish and reinforce the growing utility of this aquatic model to screen CNS therapies.

Amitriptilina serotoninérgica / Serotoninergic amitriptyline

INTRODUCCIÓN: El síndrome serotoninérgico es un cuadro clínico debido a altos niveles de serotonina. Está causado por el uso de uno o varios fármacos con actividad serotoninérgica de forma concomitante. Su diagnóstico es clínico y se lleva a cabo según criterios diagnósticos. CASO CLÍNICO: Paciente de 65años en seguimiento de larga evolución por trastorno afectivo bipolar con reciente instauración de tratamiento con amitriptilina. En urgencias se observa temblor distal, ataxia, bradipsiquia, desorientación temporoespacial, discinesia orolingual, miocolonías oculares y diaforesis. Se descartan posibles etiologías causantes del cuadro. RESULTADOS: Apareció un síndrome serotoninérgico tras la instauración de amitriptilina. No fueron necesarias medidas invasivas de soporte. Se retiró el tratamiento con psicofármacos y se instauraron progresivamente aquellos sin actividad serotoninérgica. CONCLUSIONES: No es necesario el uso concomitante de varios fármacos serotoninérgicos, sino que puede aparecer este síndrome con el uso de un fármaco instaurado de forma brusca

INTRODUCTION: Serotoninergic syndrome is a clinical disorder due to high levels of serotonin. It is caused by the concomitant use of one or several drugs with high serotoninergic activity. Its diagnosis is clinical, and is made following some diagnostic criteria. CLINICAL CASE: The case concerns a 65 year-old patient on long-term follow due to a bipolar affective disorder, and who recently started treatment with amitriptyline. In the Emergency Department, distal tremor was observed, as well as ataxia, bradypsychia, time-space orientation, orolingual dyskinesia, ocular myoclonus, and diaphoresis. Possible aetiological causes of the syndrome were ruled. RESULTS: A serotoninergic syndrome appeared after starting amitriptyline treatment. Invasive support measures were not necessary. The treatment with psychiatric drugs was withdrawn and gradually started with those without serotoninergic activity. CONCLUSIONS: The concomitant use of several serotoninergic drugs is not necessary, although this syndrome can appear with the use of a suddenly introduced drug

Molecular characterization of a vitellogenesis-inhibiting hormone (VIH) in the mud crab (Scylla olivacea) and temporal changes in abundances of VIH mRNA transcripts during ovarian maturation and following neurotransmitter administration.

The vitellogenesis-inhibiting hormone (VIH), also known as gonad-inhibiting hormone, is a neuropeptide hormone in crustaceans that belongs to the crustacean hyperglycemic hormone (CHH)-family peptide. There is regulation vitellogenesis by VIH during gonad maturation in crustaceans. A full-length Scylla olivacea VIH (Scyol-VIH) was identified through reverse transcription polymerase chain reaction and rapid amplification of cDNA ends. The open reading frame consists of 378 nucleotides, which encodes a 126-amino acid precursor protein, including a 22-residue signal peptide and a 103-amino acid mature peptide in which 6 highly conserved cysteine residues are present. There was expression of the Scyol-VIH gene in immature female Scylla olivacea in the eyestalk, brain and ventral nerve cord. The Scyol-VIH gene expression was localized to the eyestalk X-organ, brain neuronal clusters 6 and 11, and in multiple neuronal clusters of the ventral nerve cord. The relative abundance of Scyol-VIH mRNA transcript in the eyestalk was relatively greater in immature stage females, then decreased as ovarian maturation progressed. Furthermore, eyestalk Scyol-VIH increased after dopamine (5 µg/g BW) injection. The present research provides fundamental information about Scyol-VIH and its potential effect in controlling reproduction.

Brexpiprazole as Adjunctive Treatment for Major Depressive Disorder Following Treatment Failure With at Least One Antidepressant in the Current Episode: a Systematic Review and Meta-Analysis.

BACKGROUND: This systematic review and meta-analysis included double-blind, randomized, placebo-controlled trials of brexpiprazole adjunctive treatment (0.5-3 mg/d) for major depressive disorder where antidepressant treatment had failed. METHODS: The outcomes were the response rate (primary), remission rate (secondary), Montgomery Åsberg Depression Rating Scale score (secondary), Sheehan Disability Scale scores (secondary), Clinical Global Impression-Improvement/Severity scores, discontinuation rate, and individual adverse events. A subgroup meta-analysis of the data at week 6 compared outcomes by dose >2 mg/d or ≤2 mg/d (2 mg/d is the recommended dose). RESULTS: We identified 9 studies (n = 3391). Compared with placebo, brexpiprazole (any dose) was superior for response rate (risk ratio [RR] = 0.93, 95% confidence interval [95% CI] = 0.89-0.97, number needed to treat = 17), remission rate (RR = 0.95, 95% CI = 0.93-0.98, number needed to treat = 25), Montgomery Åsberg Depression Rating Scale score (standardized mean difference = -0.20, 95% CI = -0.29, -0.11), Sheehan Disability Scale score (standardized mean difference = -0.12, 95% CI = -0.21, -0.04), and Clinical Global Impression-Improvement/Severity scores but was associated with a higher discontinuation rate, akathisia, insomnia, restlessness, somnolence, and weight increase. Doses >2 mg/d had a significantly higher RR for response rate than ≤2 mg/d (0.96 vs 0.89); moreover, compared with placebo, doses >2 mg/d were associated with higher incidences of akathisia (RR = 4.58) and somnolence (RR = 7.56) as well as were marginally associated with a higher incidence of weight increase (RR = 3.14, P = .06). Compared with placebo, doses ≤2 mg/d were associated with higher incidences of akathisia (RR = 2.28) and weight increase (RR = 4.50). CONCLUSIONS: Brexpiprazole adjunctive treatment is effective for major depressive disorder when antidepressant treatment fails. At 6 weeks, doses ≤2 mg/d presented a better risk/benefit balance than >2 mg/d.

MDMA-assisted psychotherapy for treatment of PTSD: study design and rationale for phase 3 trials based on pooled analysis of six phase 2 randomized controlled trials.

BACKGROUND: Posttraumatic stress disorder is a prevalent mental health condition with substantial impact on daily functioning that lacks sufficient treatment options. Here we evaluate six phase 2 trials in a pooled analysis to determine the study design for phase 3 trials of MDMA-assisted psychotherapy for PTSD. METHODS: Six randomized, double-blind, controlled clinical trials at five study sites were conducted from April 2004 to February 2017. Active doses of MDMA (75-125 mg, n = 72) or placebo/control doses (0-40 mg, n = 31) were administered to individuals with PTSD during manualized psychotherapy sessions in two or three 8-h sessions spaced a month apart. Three non-drug 90-min therapy sessions preceded the first MDMA exposure, and three to four followed each experimental session. RESULTS: After two blinded experimental sessions, the active group had significantly greater reductions in CAPS-IV total scores from baseline than the control group [MMRM estimated mean difference (SE) between groups - 22.0 (5.17), P < 0.001]. The between-group Cohen's d effect size was 0.8, indicating a large treatment effect. After two experimental sessions, more participants in the active group (54.2%) did not meet CAPS-IV PTSD diagnostic criteria than the control group (22.6%). Depression symptom improvement on the BDI-II was greatest for the active group compared to the control group, although only trended towards significant group differences [MMRM, estimated mean difference (SE) between groups - 6.0 (3.03), P = 0.053]. All doses of MDMA were well tolerated, with some expected reactions occurring at greater frequency for the active MDMA group during experimental sessions and the 7 days following. CONCLUSIONS: MDMA-assisted psychotherapy was efficacious and well tolerated in a large sample of adults with PTSD. These studies supported expansion into phase 3 trials and led to FDA granting Breakthrough Therapy designation for this promising treatment. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT00090064, NCT00353938, NCT01958593, NCT01211405, NCT01689740, NCT01793610.

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.