Nuclear receptor TLX stimulates hippocampal neurogenesis and enhances learning and memory in a transgenic mouse model.

The role of the nuclear receptor TLX in hippocampal neurogenesis and cognition has just begun to be explored. In this study, we generated a transgenic mouse model that expresses TLX under the control of the promoter of nestin, a neural precursor marker. Transgenic TLX expression led to mice with enlarged brains with an elongated hippocampal dentate gyrus and increased numbers of newborn neurons. Specific expression of TLX in adult hippocampal dentate gyrus via lentiviral transduction increased the numbers of BrdU(+) cells and BrdU(+)NeuN(+) neurons. Furthermore, the neural precursor-specific expression of the TLX transgene substantially rescued the neurogenic defects of TLX-null mice. Consistent with increased neurogenesis in the hippocampus, the TLX transgenic mice exhibited enhanced cognition with increased learning and memory. These results suggest a strong association between hippocampal neurogenesis and cognition, as well as significant contributions of TLX to hippocampal neurogenesis, learning, and memory.

The C-terminal region of G72 increases D-amino acid oxidase activity.

The schizophrenia-related protein G72 plays a unique role in the regulation of D-amino acid oxidase (DAO) in great apes. Several psychiatric diseases, including schizophrenia and bipolar disorder, are linked to overexpression of DAO and G72. Whether G72 plays a positive or negative regulatory role in DAO activity, however, has been controversial. Exploring the molecular basis of the relationship between G72 and DAO is thus important to understand how G72 regulates DAO activity. We performed yeast two-hybrid experiments and determined enzymatic activity to identify potential sites in G72 involved in binding DAO. Our results demonstrate that residues 123-153 and 138-153 in the long isoform of G72 bind to DAO and enhance its activity by 22% and 32%, respectively. A docking exercise indicated that these G72 peptides can interact with loops in DAO that abut the entrance of the tunnel that substrate and cofactor must traverse to reach the active site. We propose that a unique gating mechanism underlies the ability of G72 to increase the activity of DAO. Because upregulation of DAO activity decreases d-serine levels, which may lead to psychiatric abnormalities, our results suggest a molecular mechanism involving interaction between DAO and the C-terminal region of G72 that can regulate N-methyl-d-aspartate receptor-mediated neurotransmission.

Clozapine protects bone mineral density in female patients with schizophrenia.

Decreased bone mineral density (BMD) is common in patients with schizophrenia; however, the pathogenesis is unclear. Different classes of antipsychotic agents may affect BMD. This study systemically examined the effects of clozapine vs. other antipsychotics, and several hormonal and metabolic factors that may contribute to BMD in female patients with schizophrenia, who are more vulnerable than males. Forty-eight women with schizophrenia, treated with long-term antipsychotics of the prototype prolactin-sparing (PS) antipsychotic agent clozapine vs. prolactin-raising (PR) antipsychotics were enrolled. They were matched for demographic and clinical characteristics. Various factors, including blood levels of prolactin and sex hormones, psychopathological symptoms, global assessment of functioning, physical activity, and menopausal status, were determined to explore their contribution to low BMD (LBMD), defined as a dual-energy X-ray absorptiometer (DEXA) T score <-1. Overall, women receiving clozapine have better bone density than women receiving PR antipsychotics. Compared to PR antipsychotics, PS clozapine therapy is a protective factor (odds ratio 28.2, 95% confidence interval 2.37-336.10, p=0.008) for LBMD. Predictors for higher bone density in the clozapine group included higher clozapine dose (p<0.001), younger age (p<0.001), and higher thyroid-stimulating hormone level (p<0.001); in the PR group, higher body mass index (p=0.003) and lower alkaline phosphatase level (p=0.007) were associated with LBMD. This study suggests that clozapine treatment is beneficial for BMD compared to PR antipsychotic treatment in women with chronic schizophrenia, and clozapine's bone-density protecting effect is dose-related.

NMDA Neurotransmission Dysfunction in Behavioral and Psychological Symptoms of Alzheimer's Disease.

Dementia has become an all-important disease because the population is aging rapidly and the cost of health care associated with dementia is ever increasing. In addition to cognitive function impairment, associated behavioral and psychological symptoms of dementia (BPSD) worsen patient's quality of life and increase caregiver's burden. Alzheimer's disease is the most common type of dementia and both behavioral disturbance and cognitive impairment of Alzheimer's disease are thought to be associated with the N-methyl-D-aspartate (NMDA) dysfunction as increasing evidence of dysfunctional glutamatergic neurotransmission had been reported in behavioral changes and cognitive decline in Alzheimer's disease. We review the literature regarding dementia (especially Alzheimer's disease), BPSD and relevant findings on glutamatergic and NMDA neurotransmission, including the effects of memantine, a NMDA receptor antagonist, and NMDA-enhancing agents, such as D-serine and D-cycloserine. Literatures suggest that behavioral disturbance and cognitive impairment of Alzheimer's disease may be associated with excitatory neurotoxic effects which result in impairment of neuronal plasticity and degenerative processes. Memantine shows benefits in improving cognition, function, agitation/aggression and delusion in Alzheimer's disease. On the other hand, some NMDA modulators which enhance NMDA function through the co-agonist binding site can also improve cognitive function and psychotic symptoms. We propose that modulating NMDA neurotransmission is effective in treating behavioral and psychological symptoms of Alzheimer's disease. Prospective study using NMDA enhancers in patients with Alzheimer's disease and associated behavioral disturbance is needed to verify this hypothesis.

Sarcosine therapy for obsessive compulsive disorder: a prospective, open-label study.

BACKGROUND: Several lines of evidence implicate glutamatergic neurotransmission in the pathophysiology of obsessive compulsive disorder (OCD). Sarcosine is an endogenous antagonist of glycine transporter-1. By blocking glycine uptake, sarcosine may increase the availability of synaptic glycine and enhance N-methyl-d-aspartate (NMDA) subtype glutamatergic neurotransmission. In this 10-week open-label trial, we examined the potential benefit of sarcosine treatment in OCD patients. METHOD: Twenty-six outpatients with OCD and baseline Yale-Brown Obsessive Compulsive Scale (YBOCS) scores higher than 16 were enrolled. Drug-naive subjects (group 1, n = 8) and those who had discontinued serotonin reuptake inhibitors for at least 8 weeks at study entry (group 2, n = 6) received sarcosine monotherapy. The other subjects (group 3, n = 12) received sarcosine as adjunctive treatment. A flexible dosage schedule of sarcosine 500 to 2000 mg/d was applied. The primary outcome measures were Y-BOCS and Hamilton Anxiety Inventory, rated at weeks 0, 2, 4, 6, 8, and 10. Results were analyzed by repeated-measures analysis of variance. RESULTS: Data of 25 subjects were eligible for analysis. The mean ± SD Y-BOCS scores decreased from 27.6 ± 5.8 to 22.7 ± 8.7, indicating a mean decrease of 19.8% ± 21.7% (P = 0.0035). Eight (32%) subjects were regarded as responders with greater than 35% reduction of Y-BOCS scores. Five of the responders achieved the good response early by week 4. Although not statistically significant, drug-naive (group 1) subjects had more profound and sustained improvement and more responders than the subjects who had received treatment before (groups 2 and 3). Sarcosine was tolerated well; only one subject withdrew owing to transient headache. CONCLUSION: Sarcosine treatment can achieve a fast therapeutic effect in some OCD patients, particularly those who are treatment naive. The study supports the glycine transporter-1 as a novel target for developing new OCD treatment. Large-series placebo-controlled, double-blind studies are recommended.

A randomized, double-blind, placebo-controlled comparison study of sarcosine (N-methylglycine) and D-serine add-on treatment for schizophrenia.

Recent evidence indicates that enhancing N-methyl-D-aspartate (NMDA) neurotransmission with the treatment of NMDA/glycine site agonists, such as D-serine, or a glycine transporter-1 (GlyT-1) antagonist, N-methylglycine (sarcosine), can improve symptoms of schizophrenia. To compare these two novel approaches, 60 patients with chronic schizophrenia were enrolled into a 6-wk double-blind, placebo-controlled trial of add-on treatments at the reported effective dosages (2 g/d). Clinical assessments were conducted every other week. Treatment group x treatment duration interaction analysis by multiple linear regression showed that sarcosine was superior to placebo at all four outcome measures of Positive and Negative Syndrome Scale (PANSS) total (p=0.005), Scale for the Assessment of Negative Symptoms (SANS) (p=0.021), Quality of Life (QOL) (p=0.025), and Global Assessment of Functioning (GAF) (p=0.042). However, d-serine did not differ significantly from placebo in any measure. Sarcosine treatment was better than d-serine in effect sizes for all outcome measures. Sarcosine also surpassed placebo in most of the measures of five PANSS factors and five SANS subscales. All treatments were well tolerated. These findings suggest that the GlyT-1 inhibitor is more efficacious than the NMDA/glycine site agonist in treatment for schizophrenia, including life quality and global function, at the dosages tested.

Low cerebrospinal fluid glutamate and glycine in refractory affective disorder.

BACKGROUND: Glutamatergic dysregulation has been documented in schizophrenia but has received less systematic study in affective illness. METHODS: Cerebrospinal fluid (CSF) levels of the excitatory amino acids glutamate (Glu) and aspartate (Asp) and the N-methyl-D-aspartate (NMDA) receptor modulator, glycine (GLY) were measured by high performance liquid chromatography in 32 patients with refractory affective disorder (16 female/16 male, 12 bipolar I, 12 bipolar II, and 8 unipolar) and in 14 age-matched controls. RESULTS: There was a significant reduction in CSF glutamate and glycine in patients versus controls. A diagnosis by sex interaction was present for CSF glycine with lower levels in female patients compared to female controls. Levels of the excitatory amino acids were highly inter-correlated in patients, but not in controls. In patients studied after 6 weeks of lamotrigine, there was a trend for CSF glutamate levels to increase. CONCLUSIONS: These data suggest that in patients with refractory affective disorder, excitatory amino acids are dysregulated, as exemplified both by the decreased CSF glutamate and glycine and their high intercorrelation compared to controls. Further controlled study of glutamatergic dysregulation and its relationship to the pathophysiology of affective disorders and potential mechanism of action of mood stabilizers appears indicated.

Ube3a mRNA and protein expression are not decreased in Mecp2R168X mutant mice.

Mutations in the transcriptional repressor methyl CpG binding protein 2 (MeCP2) are responsible for most cases of Rett Syndrome (RS), a severe neurodevelopmental disorder characterized by developmental regression, minimal speech, seizures, postnatal microcephaly and hand stereotypies. Absence of the maternal copy of ubiquitin protein ligase 3A (UBE3A) results in Angelman syndrome, also a severe developmental disorder that shares some clinical features with RS. As MeCP2 regulates gene expression, this has led to the hypothesis that MeCP2 may regulate UBE3A expression; however, there are conflicting reports regarding the expression of Ube3a in MeCP2 null mutant mice. We have generated a novel MeCP2 mutant knock-in mouse with the mutation R168X, one of the most common mutations in patients with RS. These mice show features similar to RS, including hypoactivity, forelimb stereotypies, breathing irregularities, weight changes, hind limb atrophy, and scoliosis. The male mice experience early death. Analysis of Ube3a mRNA and protein levels in the Mecp2(R168X) male mice showed no significant difference in expression compared to their wild type littermates.

Adjunctive sarcosine plus benzoate improved cognitive function in chronic schizophrenia patients with constant clinical symptoms: A randomised, double-blind, placebo-controlled trial.

Objectives Hypofunction of NMDA receptor is implicated in the pathophysiology, particularly cognitive impairment, of schizophrenia. Sarcosine, a glycine transporter I (GlyT-1) inhibitor, and sodium benzoate, a d-amino acid oxidase (DAAO) inhibitor, can both enhance NMDA receptor-mediated neurotransmission. We proposed simultaneously inhibiting DAAO and GlyT-1 may be more effective than inhibition of either in improving the cognitive and global functioning of schizophrenia patients. Methods This study compared add-on sarcosine (2 g/day) plus benzoate (1 g/day) vs. sarcosine (2 g/day) for the clinical symptoms, as well as the cognitive and global functioning, of chronic schizophrenia patients in a 12-week, double-blind, randomised, placebo-controlled trial. Participants were measured with the Positive and Negative Syndrome Scale and the Global Assessment of Functioning Scale every 3 weeks. Seven cognitive domains, recommended by the Measurement and Treatment Research to Improve Cognition in Schizophrenia Committee, were measured at weeks 0 and 12. Results Adjunctive sarcosine plus benzoate, but not sarcosine alone, improved the cognitive and global functioning of patients with schizophrenia, even when their clinical symptoms had not improved. Conclusions This finding suggests N-methyl-d-aspartate receptor-enhancement therapy can improve the cognitive function of patients with schizophrenia, further indicating this pro-cognitive effect can be primary without improvement in clinical symptoms.

D-alanine added to antipsychotics for the treatment of schizophrenia.

BACKGROUND: Hypofunction of the N-methyl-d-aspartate (NMDA) subtype glutamate receptor had been implicated in the pathophysiology of schizophrenia. Treatment with D-serine, glycine, endogenous full agonists of the glycine site of the NMDA receptor (NMDA-glycine site), D-cycloserine, a partial agonist, or sarcosine, a glycine transporter-1 inhibitor, improves the symptoms of schizophrenia. D-alanine is another endogenous agonist of the NMDA-glycine site that might have beneficial effects on schizophrenia. METHODS: Thirty-two schizophrenic patients enrolled in a 6-week double-blind, placebo-controlled trial of D-alanine (100 mg/kg/day), which was added to their stable antipsychotic regimens. Measures of clinical efficacy and side effects were determined every other week. RESULTS: Patint who received D-alanine treatment revealed significant reductions in their Clinical Global Impression Scale and Positive and Negative Syndrome Scale (PANSS) total scores. The Scale for the Assessment of Negative Symptoms and PANSS subscores of positive and cognitive symptoms were improved. D-alanine was well tolerated, and no significant side effect was noted. CONCLUSIONS: The significant improvement with the D-alanine further supports the hypothesis of hypofunction of NMDA neurotransmission in schizophrenia and strengthens the proof of the principle that NMDA-enhancing treatment is a promising approach for the pharmacotherapy of schizophrenia.

Sarcosine or D-serine add-on treatment for acute exacerbation of schizophrenia: a randomized, double-blind, placebo-controlled study.

CONTEXT: Agents that enhance N-methyl-D-aspartate (NMDA) function through the glycine modulatory site (D-serine, glycine, or D-cycloserine) or through glycine transporter 1 (sarcosine) improve the symptoms of patients with stable chronic schizophrenia. OBJECTIVE: To determine whether NMDA-glycine site agonists or glycine transporter-1 inhibitors have better efficacy and whether NMDA receptor-enhancing agents have beneficial effects for acute exacerbation of schizophrenia. DESIGN: Randomized, double-blind, placebo-controlled trial. SETTING: Inpatient units of 2 major medical centers in Taiwan. Patients Sixty-five schizophrenic inpatients with acute exacerbation. INTERVENTIONS: Six weeks of treatment with sarcosine (2 g/d), D-serine (2 g/d), or placebo and concomitant optimal risperidone therapy. MAIN OUTCOME MEASURES: Positive and Negative Syndrome Scale (PANSS) and Scale for the Assessment of Negative Symptoms (SANS) (20 and 17 items) total scores. RESULTS: The sarcosine group revealed more reductions in PANSS total scores than the placebo (P = .04) and D-serine (P<.001) groups. Sarcosine adjunctive treatment was also superior to placebo in reducing SANS-20 (P = .007) and SANS-17 (P = .003) scores and to D-serine in decreasing SANS-20 (P = .006) and SANS-17 (P = .002) scores. The PANSS-general, PANSS-cognitive, and PANSS-depressive symptoms scores and SANS-alogia and SANS-blunted affect scores improved significantly more in sarcosine-cotreated patients than in risperidone monotherapy patients (P< or =.02 for all). Sarcosine adjunctive therapy also surpassed D-serine in terms of PANSS-general, PANSS-positive, PANSS-negative, and PANSS-depressive symptoms scores (P< or =.04 for all). D-serine and risperidone cotreatment did not differ significantly from risperidone monotherapy in all efficacy domains. CONCLUSIONS: This first short-term treatment study on NMDA receptor-enhancing agents suggests that sarcosine, superior to D-serine, can benefit not only patients with long-term stable disease but also acutely ill persons with schizophrenia. This finding indicates that a glycine transporter 1 inhibitor may be more efficacious than NMDA-glycine site agonists for adjuvant treatment of schizophrenia, at least during the acute phase. Further studies are needed.

Sarcosine treatment for oppositional defiant disorder symptoms of attention deficit hyperactivity disorder children.

Methylphenidate, a stimulant that activates dopaminergic and noradrenergic function, is an important agent in the treatment of attention deficit hyperactivity disorder (ADHD). Sarcosine, a glycine transporter-1 inhibitor, may also play a role in treating ADHD by modulating the glutamatergic neurotransmission system through activating N-methyl-D-aspartate type glutamate receptors. This study aimed to assess the efficacy of sarcosine in treating children with ADHD. We conducted a six-week, randomized, double-blind, placebo-controlled clinical trial. The primary outcome measures were those on the Inattention, Hyperactivity/impulsivity, and oppositional defiant disorder (ODD) subscales of the Swanson, Nolan, and Pelham, version IV scale. Efficacy and safety were measured bi-weekly. A total of 116 children with ADHD were enrolled. Among them, 48 (83%) of the 58 sarcosine recipients and 44 (76%) of the 58 placebo recipients returned for the first post-treatment visit. The missing data values were imputed by the last observation carry forward method. From a multiple linear regression analysis, using the generalized estimating equation approach, and an intention to treat analysis, the efficacy of sarcosine marginally surpassed that of placebo at weeks 2, 4, and 6, with p-values=0.01, 0.026, and 0.012, respectively, although only for ODD symptoms. Treatment of ADHD by sarcosine (0.03 g/kg/day) was well tolerated. Sarcosine could possibly be a novel agent for managing ODD symptoms in the context of ADHD. However, future larger-scale studies are warranted to optimize its dosage.

Assessing the construct validity of the Chinese-Version Schizotypal Personality Questionnaire-Brief on male and female undergraduate students.

BACKGROUND: Screening for the schizotypal personality trait is one strategy to identify people who may be susceptible to early psychosis or be at high risk for prodromal psychosis. The Schizotypal Personality Questionnaire-Brief (SPQ-B) has been widely used to assess the schizotypal personality and has been translated into Chinese. However, the psychometric properties of the Chinese-version scale have yet to be evaluated. PURPOSE: This study evaluates the construct validity of the Chinese-version SPQ-B on a sample of male and female undergraduate students in Taiwan. METHODS: A cross-sectional design with convenient sampling was used for this study. The data were collected using the Chinese-version SPQ-B between October 2008 and June 2009. Participants included 513 male and 675 female undergraduate students in Taiwan. The factor construct validity of the scale was examined by confirmatory factor analysis using structural equation modeling with SPSS AMOS version 17 software. RESULTS: The results show that the three-factor model fits the data better than the one-factor model for both male and female participants. The male participants scored significantly higher than their female counterparts in terms of total scale, interpersonal subscales, and disorganized subscales. CONCLUSIONS/IMPLICATIONS FOR PRACTICE: The Chinese version of the SPQ-B adequately achieves three-factor construct validity for undergraduate students. The scale may be used to screen for the schizotypal personality trait in both male and female college students to identify those at an elevated risk for mental illness.

NMDA pathology and treatment of schizophrenia.

Schizophrenia, a multifactorial mental disorder with polygenic inheritance as well as environmental influences, encompasses a characteristic group of symptoms. Negative and cognitive symptoms which respond poorly to currently available antipsychotics remain a great clinical challenge. Aggressive studies are ongoing to explore the etiological mechanisms of this disease. Among them, one of the primary causal factors is dysfunction of the N-methyl-D-aspartate (NMDA)-type glutamate receptors. This article reviews the clinical manifestations of the disease, limitations of current antipsychotics and reconceptualization of the nature of disease and treatment modalities based on the evidence provided by drug models, genetic studies, and clinical trials. The NMDA receptor (NMDAR) model plays a critical role in the revolution of pharmaceutical industry as a new set of drug targets is proposed. Investigations on the modulation of glutamatergic system, particularly the intrinsic NMDA glycine modulatory site, exhibit encouraging results. A group of "NMDA-enhancing agents" either acts directly or indirectly on the glycine modulatory site, showing therapeutic efficacy in preclinical and early clinical trials. A new generation of therapeutic agents targeting the NMDAR shows promise as the next wave of drug development for schizophrenia.

Assessing and treating cognitive impairment in schizophrenia: current and future.

Schizophrenia is a serious neuropsychiatric disease characterized by positive symptoms, negative symptoms and cognitive impairment. Evidence have shown that cognitive impairment sustains in every clinical stage, may relate with the liability, may predict functional outcome in schizophrenia and could be the core symptom of schizophrenia. The treatment of cognitive impairment in schizophrenia could alleviate the burden of the illness and has become the subject of intensive research. In this review, we synthesize current advances of assessing strategies, pharmacological and non-pharmacological treatments of cognitive impairment in schizophrenia. According to the registered records of ClinicalTrials.gov, the most widely studied strategies have aimed at modifying neurochemical mechanisms of dopamine metabolism, glutamate metabolism, γ-aminobutyric acid (GABA) metabolism, serotonin metabolism, acetylcholine metabolism, and oxytocin. Despite preclinical data for putative pro-cognitive drugs, their clinical benefits for schizophrenia patients have been limited. The small sample sizes and the short treatment duration could be related with the suboptimal results. Evidence supported the short-term benefits of cognitive remediation therapy on cognitive domains with small to moderate effects; however, the small sample sizes and the characteristics of subjects limited the generalization of the positive results and the long-term functional outcome is not clear. Combination therapy is promising, by integrating pro-cognitive agents and cognitive rehabilitation programs or combining two kinds of pro-cognitive agents via different mechanisms. Future studies should investigate the pro-cognitive drugs' long-term efficacy, rebound deterioration in psychosis/cognition following discontinuation, and related biomarkers of functional outcome.

Attention deficit hyperactivity disorder and N-methyl-D-aspartate (NMDA) dysregulation.

Attention deficit hyperactivity disorder (ADHD) is a long recognized and common childhood disorder. ADHD adolescents tend to encounter more difficulties in school and peer relationships, whereas ADHD adults have more occupational and interpersonal difficulties. However, with the treatment of central nervous system (CNS) stimulants, 10-20 % of the patients still remain poor responders to treatment. Among hypotheses for ADHD, dysfunction of N-methyl-D-aspartate (NMDA)-type glutamate receptors has recently been suggested by accumulating genetic and animal studies. This article systemically reviews evidence supporting NMDA dysfunction as a potential ADHD pathogenesis from perspectives of neurodevelopment, attentional circuitry, and impulse inhibition. The review also addresses the development of novel treatments for ADHD via modulation of glutamatergic system, particularly the NMDA/glycine site. These so-called NMDA enhancers may provide a new treatment option for patients with ADHD.

NMDA neurotransmission dysfunction in mild cognitive impairment and Alzheimer's disease.

The prevalence of Alzheimer's disease (AD) in the elderly is growing rapidly worldwide, and the deteriorating clinical course of AD places a heavy burden on both the patients and their families. Early detection and intervention of mild cognitive impairment in the early phase of AD is vital for the purpose of improving the cognitive performance of patients and preventing the existing deficits from worsening. However, the main compounds currently used to treat early AD, acetylcholinesterase inhibitors (AChEIs), are unsatisfactory in efficacy and safety. Moreover, evidence indicates that AChEIs are ineffective in treating AD at extremely early stages, which implies that mechanisms other than those targeted by AChEIs underlie the pathogenesis of AD. Dysfunctional glutamatergic neurotransmission, particularly that mediated by the N-methyl-D-aspartate (NMDA) receptor, has been reported to play a role in the pathophysiology of AD. The NMDA receptor (NMDAR) regulates synaptic plasticity, memory, and cognition, and the attenuation of NMDAR-mediated neurotransmission can result in impaired neuroplasticity and cognitive deficits in the aging brain. Furthermore, NMDARs also interact with amyloid beta peptide/amyloid precursor protein and tau protein, whose production represents the main manifestations of AD. In this paper, we review the evidence supporting NMDA dysfunction in both animal models of AD and patients afflicted with AD, and we also review the literature that suggests that NMDA-enhancing agents such as glycine and D-cycloserine can improve cognitive functions. The benefits and limitations of NMDAR antagonists that can diminish the excitatory neurotoxicity triggered by glutamate are also addressed in relation to AD. We propose that enhancing glutamatergic neurotransmission by activating the NMDAR may be effective in treating the cognitive decline that occurs in AD. Prospective studies on AD in which NMDA-enhancing agents are used are required to verify this hypothesis and confirm the long-term efficacy and safety of the treatment agents.

Effectiveness of aripiprazole, olanzapine, quetiapine, and risperidone augmentation treatment for major depressive disorder: a nationwide population-based study.

OBJECTIVE: Previous studies suggested that antidepressants augmented with second-generation antipsychotics (SGAs), including aripiprazole, olanzapine, quetiapine, and risperidone, resulted in better treatment response or higher rates of remission in patients with major depressive disorder (MDD). However, population-based study on SGA augmentation for patients with MDD remains limited. The purpose of this study was to investigate the effectiveness of SGA augmentation for treatment of MDD using the National Health Insurance Research Database in Taiwan. METHOD: The subjects were patients with MDD (ICD-9-CM code: 296.2 and 296.3) who were initially admitted to psychiatric inpatient settings for the first time between January 1, 1996, and December 31, 2007, and could be tracked until December 31, 2011. To assess the treatment effect of SGA augmentation, 993 MDD patients who received aripiprazole, olanzapine, quetiapine, or risperidone augmentation treatment for 8 weeks or more were included in this 1-year mirror-image study. Outcome measures included length of psychiatric hospitalization and number of psychiatric admissions and emergency room (ER) visits. RESULTS: After patients received SGA augmentation treatment, key psychiatric service use (including length of psychiatric hospitalization [P < .0001], number of psychiatric admissions [P < .0001], and ER visits [P = .0006]) due to MDD diagnosis was significantly reduced. Subgrouping analysis for each SGA drug also showed significant reduction in number of psychiatric admissions for MDD patients who received aripiprazole (P < .0001), olanzapine (P = .003), quetiapine (P < .0001), and risperidone (P < .0001). CONCLUSIONS: The study provides support that aripiprazole, olanzapine, quetiapine, and risperidone augmentation therapy could be effective in reducing psychiatric service utilization among MDD patients.

Benzoate, a D-amino acid oxidase inhibitor, for the treatment of early-phase Alzheimer disease: a randomized, double-blind, placebo-controlled trial.

BACKGROUND: N-methyl-D-aspartate receptor (NMDAR)-mediated neurotransmission is vital for learning and memory. Hypofunction of NMDAR has been reported to play a role in the pathophysiology of Alzheimer disease (AD), particularly in the early phase. Enhancing NMDAR activation might be a novel treatment approach. One of the methods to enhance NMDAR activity is to raise the levels of NMDA coagonists by blocking their metabolism. This study examined the efficacy and safety of sodium benzoate, a D-amino acid oxidase inhibitor, for the treatment of amnestic mild cognitive impairment and mild AD. METHODS: We conducted a randomized, double-blind, placebo-controlled trial in four major medical centers in Taiwan. Sixty patients with amnestic mild cognitive impairment or mild AD were treated with 250-750 mg/day of sodium benzoate or placebo for 24 weeks. Alzheimer's Disease Assessment Scale-cognitive subscale (the primary outcome) and global function (assessed by Clinician Interview Based Impression of Change plus Caregiver Input) were measured every 8 weeks. Additional cognition composite was measured at baseline and endpoint. RESULTS: Sodium benzoate produced a better improvement than placebo in Alzheimer's Disease Assessment Scale-cognitive subscale (p = .0021, .0116, and .0031 at week 16, week 24, and endpoint, respectively), additional cognition composite (p = .007 at endpoint) and Clinician Interview Based Impression of Change plus Caregiver Input (p = .015, .016, and .012 at week 16, week 24, and endpoint, respectively). Sodium benzoate was well-tolerated without evident side-effects. CONCLUSIONS: Sodium benzoate substantially improved cognitive and overall functions in patients with early-phase AD. The preliminary results show promise for D-amino acid oxidase inhibition as a novel approach for early dementing processes.