Comparison between olanzapine and aripiprazole treatment for 104 weeks after hospital discharge in schizophrenia spectrum disorders: a multicenter retrospective cohort study in a real-world setting.

RATIONALE: The long-term effectiveness of olanzapine and aripiprazole in real clinical conditions at flexible doses in patients after hospital discharge has not been evaluated yet. OBJECTIVES: This study was a multicenter retrospective cohort study. Patients with schizophrenia (n = 398) were prescribed olanzapine (n = 303) or aripiprazole (n = 95) at hospital discharge. The continuation of olanzapine or aripiprazole at 26, 52, or 104 weeks after the hospital discharge were compared using a Cox proportional hazards model and adjusted for possible confounders. RESULTS: The Kaplan-Meier survival curves revealed that the continuation of olanzapine at 26 (P = 0.001) and 52 weeks (P = 0.018) was significantly higher than that of aripiprazole but not at 104 weeks. Olanzapine was better than aripiprazole in efficacy at 26 (hazard ratio: 0.321, 95% confidence interval: 0.159-0.645, P = 0.001), 52 (hazard ratio: 0.405, 95% confidence interval: 0.209-0.786, P = 0.008), and 104 weeks (hazard ratio: 0.438, 95% confidence interval: 0.246-0.780, P = 0.005). Aripiprazole was better than olanzapine in tolerability at 104 weeks (hazard ratio: 4.574, 95% confidence interval: 1.415-14.787, P = 0.011). Rates after two years continuation of olanzapine and aripiprazole were not significantly different in patients with less than five years' duration of illness, but olanzapine was more commonly maintained for more than two years in those patients who had been ill for over five years' due to its greater efficacy. CONCLUSION: Olanzapine treatment showed better continuation rates at 26 and 52 after hospital discharge than aripiprazole, whereas maintenance with the two antipsychotics did not differ significantly at 104 weeks, due reduced tolerability of long-term olanzapine treatment.

Initial Outcomes of the Safe and Sound Protocol on Patients with Adult Autism Spectrum Disorder: Exploratory Pilot Study.

Sensory impairments are common features of autism spectrum disorder (ASD) and are associated with its social impairments. However, there is no established treatment for these impairments in adults with ASD. The Safe & Sound Protocol (SSP) is a listening program designed to improve social communication skills by reducing auditory hypersensitivity. We investigated the effectiveness of the SSP for adults with ASD. We administered the SSP to six participants with ASD aged 21-44 years old, and the effects were assessed using the Social Responsiveness Scale, Second Edition (SRS-2). Secondary outcomes were assessed using the Center for Epidemiological Studies Depression Scale (CES-D), State-Trait Anxiety Inventory (STAI), WHO Quality of Life 26 (WHOQOL-BREF), and Adolescent/Adult Sensory Profile (A/ASP). In this study, only the Social Awareness scale of the SRS-2 Family-Report showed a significant improvement after the intervention. In addition, it was significantly correlated with physical health of WHOQOL-BREF (r = -0.577, p = 0.012), state and trait anxiety of STAI (r = 0.576, p = 0.012; r = 0.708, p = 0.00009, respectively), and CES-D (r = 0.465, p = 0.05). In conclusion, the SSP has a partial effect on social impairments in adults with ASD, specifically on the Social Awareness subscale of the SRS-2.

The validity of atypical psychosis diagnostic criteria to detect anti-NMDA receptor encephalitis with psychiatric symptoms.

Anti-NMDAR encephalitis has a psychotic presentation that is difficult to distinguish from primary psychosis. An atypical psychosis that is similar to schizophrenia, mood disorder, and epilepsy is unique, and the original diagnostic criteria exist only in Japan. The clinical symptoms and courses of anti-NMDAR encephalitis and atypical psychosis are very similar. We investigated whether the diagnostic criteria of atypical psychosis are useful to increase the detection rate of anti-NMDAR encephalitis with psychiatric symptoms. The presence of anti-NR1/NR2B IgG antibodies in the cerebrospinal fluid of 218 newly admitted inpatients initially diagnosed with schizophrenia (n = 151), mood disorder (n = 47), or epilepsy with psychiatric symptoms (n = 20) was assessed by cell-based assay. Of 218 patients, 123 (36.3 years ± SD 17.2, 69.9 % females) fulfilled the diagnostic criteria of category B for atypical psychosis. All 12 patients (9.8 %, 12/123) with anti-NR1/NR2B IgG antibodies fulfilled category B of atypical psychosis statistically better than the patients without anti-NR1/NR2B IgG antibodies (P = 0.0009). Of the 12 patients with anti-NMDAR antibodies, two did not fulfill either criteria of catatonia (DSM-5) or Graus' diagnostic criteria of anti-NMDAR encephalitis during the time course, and 11 patients showed good prognosis with early immunotherapies. In ROC analysis, abnormal electroencephalogram findings showed the highest sensitivity (0.833) for detection of anti-NR1/NR2B IgG antibodies, and 31.3 % of patients with category B atypical psychosis and abnormal electroencephalogram findings had anti-NMDAR antibodies. Lumbar puncture and detection of anti-NMDAR antibodies should be considered for patients who fulfill atypical psychosis diagnosis criteria with an abnormal electroencephalogram.

Transdiagnostic comparisons of intellectual abilities and work outcome in patients with mental disorders: multicentre study.

BACKGROUND: Cognitive impairment is common in people with mental disorders, leading to transdiagnostic classification based on cognitive characteristics. However, few studies have used this approach for intellectual abilities and functional outcomes. AIMS: The present study aimed to classify people with mental disorders based on intellectual abilities and functional outcomes in a data-driven manner. METHOD: Seven hundred and forty-nine patients diagnosed with schizophrenia, bipolar disorder, major depression disorder or autism spectrum disorder and 1030 healthy control subjects were recruited from facilities in various regions of Japan. Two independent k-means cluster analyses were performed. First, intelligence variables (current estimated IQ, premorbid IQ, and IQ discrepancy) were included. Second, number of work hours per week was included instead of premorbid IQ. RESULTS: Four clusters were identified in the two analyses. These clusters were specifically characterised in terms of IQ discrepancy in the first cluster analysis, whereas the work variable was the most salient feature in the second cluster analysis. Distributions of clinical diagnoses in the two cluster analyses showed that all diagnoses were unevenly represented across the clusters. CONCLUSIONS: Intellectual abilities and work outcomes are effective classifiers in transdiagnostic approaches. The results of our study also suggest the importance of diagnosis-specific strategies to support functional recovery in people with mental disorders.

Clinical moderators of response to nalmefene in a randomized-controlled trial for alcohol dependence: An exploratory analysis.

BACKGROUND: Nalmefene is the only medication marketed to reduce the consumption of alcohol in patients with alcohol dependence, but it remains unclear which patients could most benefit from it. This study aimed to identify clinical moderators that affect treatment response to nalmefene in patients with alcohol dependence. METHODS: In a multicenter, randomized, controlled, double-blind, phase 3 study of nalmefene on Japanese patients with alcohol dependence, the relationship between the reduction of heavy drinking days (HDD) and total alcohol consumption (TAC) at 12 and 24 weeks of treatment and baseline variables of the participants were analyzed in a linear regression and multiple adjusted analysis. RESULTS: Age < 65, no family history of problem drinking, age at onset of problem drinking ≥ 25, and not currently smoking were possible positive moderators. Nalmefene showed a significant HDD reduction in patients with age < 65 or no family history of problem drinking, and a significant TAC reduction in patients with age at onset of problem drinking ≥ 25 or who were not currently smoking. After multiple adjusted analyses, age < 65 (p = .028), no family history of problem drinking (p = .047), and age at onset of problem drinking ≥ 25 (p = .030) were statistically significant. Not currently smoking (p = .071) was marginally significant. In combination, these moderators indicated synergistic effects. CONCLUSIONS: Alcohol-dependent patients with favorable prognostic factors such as non-smoking status, no family history of problem drinking, and a late-onset of problem drinking selectively benefit from nalmefene. Further research is needed to validate these exploratory results.

Association between depression in chronic phase and future clinical outcome of patients with schizophrenia.

RATIONALE: Depression in schizophrenia is an important symptom. We investigated whether depression and suicidal symptoms in the chronic phase are related to remote future clinical outcomes in patients with schizophrenia and whether psychotropics improved clinical outcomes. OBJECTIVES: The subjects included 462 outpatients of working age (15 to 64 years old) with schizophrenia treated at Okayama University Hospital from January 2010 to December 2011. We investigated the relationship between the Clinical Global Impression-Severity score at the last visit (average 19.2 years) and the existence of previous depression, suicidal ideas, and suicide attempts. We adjusted by several possible confounders including medical history using multiple regression analysis or logistic regression analysis. RESULTS: Of 462 patients, 168 (36.4%) presented with depression 2 years after schizophrenia onset. A history of suicidal ideas and attempts was related to worse clinical outcome. In males, a history of depression was related to worse clinical outcome, but not in females. Lithium carbonate was related to better clinical outcome in all schizophrenia patients with depression, especially in males. Treatment with antidepressants was related to better clinical outcome only in males. CONCLUSIONS: A history of depression or suicidal symptoms in the chronic phase predicted the future worse clinical outcome in patients with schizophrenia. The administration of lithium carbonate or antidepressants might be recommended, especially to male schizophrenia patients with depression.

Impairment of early neuronal maturation in anti-NMDA-receptor encephalitis.

RATIONALE: Adequate immunotherapies for anti-NMDAR encephalitis during pregnancy produce a relatively good clinical outcome for pregnant mothers and their infants, but there are no reports about the future growth of their babies. The damage of anti-NMDAR antibodies to early neuronal development is still unknown. OBJECTIVES: Serum or cerebrospinal fluid from one patient with anti-NMDAR encephalitis (the index patient) and one patient with schizophrenia (the control patient) was administered to primary cultures of dissociated rat cortical neurons, and dendritic outgrowth, centrosome elimination, and branching of dendrites were investigated. For rescue experiments, serum of the index patient was replaced with normal culture media after 3 days' administration of the index patient. RESULTS: Serum and cerebrospinal fluid of the index patient statistically significantly impaired dendritic outgrowth of cultured rat cortical primary neurons. Serum of the index patient also statistically significantly delayed centrosome elimination. Impaired dendritic outgrowth and delayed centrosome elimination were not perfectly rescued by changing to normal culture media. Serum of the index patient also statistically significantly reduced the branching of dendrites. CONCLUSIONS: This is the first demonstration of the damage by anti-NMDAR antibodies on early dendritic development in vitro. As a strategy to protect embryonic neurons, our findings may support the efficacy of early immunotherapy for anti-NMDAR encephalitis in pregnancy.

Mirtazapine Was Effective for a Patient With Benzodiazepine Dependence.

OBJECTIVE: Benzodiazepine (BZD) dependence has become a social problem and results in poor outcomes. Only a few evidence-based treatments for pharmacotherapy, including antidepressants, are recommended. METHODS: We reported about a 71-year-old man with onset of blindness at 50 years of age due to pigmentary degeneration of the retina developed insomnia at age 59 years, characterized by nocturnal and early morning awakenings. RESULTS: Mirtazapine was effective to not only treat sleep disturbance but also a craving for BZD. CONCLUSIONS: The increases of dopamine, norepinephrine, and serotonin signaling by mirtazapine may be related to the effectiveness in reducing BZD dependence.

The relationship between plasma clozapine concentration and clinical outcome: a cross-sectional study.

OBJECTIVE: There is no report that statistically evaluates the therapeutic reference (350-600 ng/ml) and adverse drug reaction (ADR) range (>1000 ng/ml) of clozapine (CLZ) recommended by the Arbeitsgemeinschaft für Neuropsychopharmakologie und Pharmakopsychiatrie (AGNP) consensus guidelines in an isolated and large sampling study. METHODS: We administered CLZ to 131 Japanese patients with treatment-resistant schizophrenia in a multicenter cross-sectional study. Plasma CLZ concentrations were assayed by high-performance liquid chromatography using trough sampling. The Brief Psychiatric Rating Scale (BPRS) and severe dose-dependent ADR (sedation, myoclonus, and seizures) were analyzed statistically after adjusting for possible confounders. RESULTS: The daily CLZ dosage showed a moderately positive relationship with the plasma concentration (r = 0.49, p < 0.001). Every 100 ng/ml increase in plasma CLZ concentration improved the total BPRS score 1.95% (95% CI: 0.89-3.01, p < 0.001) and the odds ratio (OR) 1.38 (95% CI: 1.14-1.66, p = 0.001) for BPRS response. Compared with concentrations below 350 ng/ml CLZ, 350-600 ng/ml (11.12%; 95% CI: 2.52-19.72, p = 0.012) and 600-1000 ng/ml (11.05%; 95% CI: 2.40-19.71, p = 0.013) showed significant improvement in the total BPRS score. Dosages above 1000 ng/ml showed greater improvement (25.36%; 95% CI: 13.08-37.64, p < 0.001) of the total BPRS score but more severe ADRs than dosages below 1000 ng/ml (OR: 31.72; 95% CI: 1.04-968.81, p = 0.048). CONCLUSION: The AGNP therapeutic reference range (350-600 ng/ml) is useful, and a dose above 1000 ng/ml is potentially more effective but carries the risk of severe ADRs in the central nervous system.

Mechanisms Underlying the Comorbidity of Schizophrenia and Type 2 Diabetes Mellitus.

The mortality rate of patients with schizophrenia is high, and life expectancy is shorter by 10 to 20 years. Metabolic abnormalities including type 2 diabetes mellitus (T2DM) are among the main reasons. The prevalence of T2DM in patients with schizophrenia may be epidemiologically frequent because antipsychotics induce weight gain as a side effect and the cognitive dysfunction of patients with schizophrenia relates to a disordered lifestyle, poor diet, and low socioeconomic status. Apart from these common risk factors and risk factors unique to schizophrenia, accumulating evidence suggests the existence of common susceptibility genes between schizophrenia and T2DM. Functional proteins translated from common genetic susceptibility genes are known to regulate neuronal development in the brain and insulin in the pancreas through several common cascades. In this review, we discuss common susceptibility genes, functional cascades, and the relationship between schizophrenia and T2DM. Many genetic and epidemiological studies have reliably associated the comorbidity of schizophrenia and T2DM, and it is probably safe to think that common cascades and mechanisms suspected from common genes' functions are related to the onset of both schizophrenia and T2DM. On the other hand, even when genetic analyses are performed on a relatively large number of comorbid patients, the results are sometimes inconsistent, and susceptibility genes may carry only a low or moderate risk. We anticipate future directions in this field.

Rare single-nucleotide DAB1 variants and their contribution to Schizophrenia and autism spectrum disorder susceptibility.

Disabled 1 (DAB1) is an intracellular adaptor protein in the Reelin signaling pathway and plays an essential role in correct neuronal migration and layer formation in the developing brain. DAB1 has been repeatedly reported to be associated with neurodevelopmental disorders including schizophrenia (SCZ) and autism spectrum disorders (ASD) in genetic, animal, and postmortem studies. Recently, increasing attention has been given to rare single-nucleotide variants (SNVs) found by deep sequencing of candidate genes. In this study, we performed exon-targeted resequencing of DAB1 in 370 SCZ and 192 ASD patients using next-generation sequencing technology to identify rare SNVs with a minor allele frequency <1%. We detected two rare missense mutations (G382C, V129I) and then performed a genetic association study in a sample comprising 1763 SCZ, 380 ASD, and 2190 healthy control subjects. Although no statistically significant association with the detected mutations was observed for either SCZ or ASD, G382C was found only in the case group, and in silico analyses and in vitro functional assays suggested that G382C alters the function of the DAB1 protein. The rare variants of DAB1 found in the present study should be studied further to elucidate their potential functional relevance to the pathophysiology of SCZ and ASD.

Rare genetic variants in the gene encoding histone lysine demethylase 4C (KDM4C) and their contributions to susceptibility to schizophrenia and autism spectrum disorder.

Dysregulation of epigenetic processes involving histone methylation induces neurodevelopmental impairments and has been implicated in schizophrenia (SCZ) and autism spectrum disorder (ASD). Variants in the gene encoding lysine demethylase 4C (KDM4C) have been suggested to confer a risk for such disorders. However, rare genetic variants in KDM4C have not been fully evaluated, and the functional impact of the variants has not been studied using patient-derived cells. In this study, we conducted copy number variant (CNV) analysis in a Japanese sample set (2605 SCZ and 1141 ASD cases, and 2310 controls). We found evidence for significant associations between CNVs in KDM4C and SCZ (p = 0.003) and ASD (p = 0.04). We also observed a significant association between deletions in KDM4C and SCZ (corrected p = 0.04). Next, to explore the contribution of single nucleotide variants in KDM4C, we sequenced the coding exons in a second sample set (370 SCZ and 192 ASD cases) and detected 18 rare missense variants, including p.D160N within the JmjC domain of KDM4C. We, then, performed association analysis for p.D160N in a third sample set (1751 SCZ and 377 ASD cases, and 2276 controls), but did not find a statistical association with these disorders. Immunoblotting analysis using lymphoblastoid cell lines from a case with KDM4C deletion revealed reduced KDM4C protein expression and altered histone methylation patterns. In conclusion, this study strengthens the evidence for associations between KDM4C CNVs and these two disorders and for their potential functional effect on histone methylation patterns.

Functional characterization of rare NRXN1 variants identified in autism spectrum disorders and schizophrenia.

BACKGROUND: Rare genetic variants contribute to the etiology of both autism spectrum disorder (ASD) and schizophrenia (SCZ). Most genetic studies limit their focus to likely gene-disrupting mutations because they are relatively easier to interpret their effects on the gene product. Interpretation of missense variants is also informative to some pathophysiological mechanisms of these neurodevelopmental disorders; however, their contribution has not been elucidated because of relatively small effects. Therefore, we characterized missense variants detected in NRXN1, a well-known neurodevelopmental disease-causing gene, from individuals with ASD and SCZ. METHODS: To discover rare variants with large effect size and to evaluate their role in the shared etiopathophysiology of ASD and SCZ, we sequenced NRXN1 coding exons with a sample comprising 562 Japanese ASD and SCZ patients, followed by a genetic association analysis in 4273 unrelated individuals. Impact of each missense variant detected here on cell surface expression, interaction with NLGN1, and synaptogenic activity was analyzed using an in vitro functional assay and in silico three-dimensional (3D) structural modeling. RESULTS: Through mutation screening, we regarded three ultra-rare missense variants (T737M, D772G, and R856W), all of which affected the LNS4 domain of NRXN1α isoform, as disease-associated variants. Diagnosis of individuals with T737M, D772G, and R856W was 1ASD and 1SCZ, 1ASD, and 1SCZ, respectively. We observed the following phenotypic and functional burden caused by each variant. (i) D772G and R856W carriers had more serious social disabilities than T737M carriers. (ii) In vitro assay showed reduced cell surface expression of NRXN1α by D772G and R856W mutations. In vitro functional analysis showed decreased NRXN1α-NLGN1 interaction of T737M and D772G mutants. (iii) In silico 3D structural modeling indicated that T737M and D772G mutations could destabilize the rod-shaped structure of LNS2-LNS5 domains, and D772G and R856W could disturb N-glycan conformations for the transport signal. CONCLUSIONS: The combined data suggest that missense variants in NRXN1 could be associated with phenotypes of neurodevelopmental disorders beyond the diagnosis of ASD and/or SCZ.

Switching strategies for antipsychotic monotherapy in schizophrenia: a multi-center cohort study of aripiprazole.

RATIONALE: Changing antipsychotics of patients with chronic schizophrenia involves several risks. Switching to aripiprazole is especially difficult. We investigated switching methods and related factors for successful switching patients with chronic schizophrenia to aripiprazole. OBJECTIVES: This study was a multi-center historical cohort study and approved by the research ethics committee of Okayama University Hospital and Okayama Psychiatric Medical Center. We compared survival proportions of 178 chronic schizophrenia patients who continued aripiprazole monotherapy for 6 months after non-direct switching (add-on switching (n = 45), cross switching (n = 62)) or direct switching (n = 71). We adjusted possible confounders using a Cox proportional hazards model. RESULTS: Of patients with chronic schizophrenia, 56.7% (101/178) were switched to aripiprazole monotherapy, and 55.0% (98/178) showed improvement in symptoms as demonstrated by the Clinical Global Impression Severity score. Kaplan-Meier survival curves showed that non-direct switching had a higher survival proportion than direct switching (log-rank test, p = 0.012). Even after adjusting for several variables using a Cox proportional hazards model, add-on switching had a significantly lower hazard at 6 months than direct switching (hazard ratio 0.42, 95% confidence interval 0.21-0.82, P = 0.01). In cases of switching to aripiprazole for psychiatric symptoms, non-direct switching had a lower hazard than direct switching (hazard ratio 0.41, 95% confidence interval 0.21-0.81, P = 0.01) but was not significant for adverse reaction. When aripiprazole was switched from olanzapine, add-on switch showed the lowest hazard ratio for continuation (hazard ratio 0.29, 95% confidence interval 0.07-1.11, P = 0.07). CONCLUSIONS: Flexibility in strategies when switching to aripiprazole may induce a better outcome for patients with chronic schizophrenia.

Anti-NMDA-receptor antibody in initial diagnosis of mood disorder.

Anti-NMDAR encephalitis is increasingly recognized as one etiology of psychiatric symptoms, but there is not enough evidence on patients with mood disorder. We assayed anti-NR1/NR2B IgG antibodies in serum and/or cerebrospinal fluid of 62 patients initially diagnosed with mood disorder by a cell-based assay. We also investigated the specific patient characteristics and psychotic symptoms. At first admission, the patients showed only psychiatric symptoms without typical neurological signs or abnormal examination findings. Four of the 62 patients had anti-NR1/NR2B IgG antibodies. The anti-NR1/NR2B IgG antibody-positive patients showed more super- or abnormal sensitivity (P = 0.00088), catatonia (P = 0.049), and more conceptual disorganization (P < 0.0001), hostility (P = 0.0010), suspiciousness (P < 0.0001), and less emotional withdrawal (P < 0.0001) and motor retardation (P < 0.0001) on the Brief Psychiatric Rating Scale than the antibody-negative patients. During the clinical course, anti-NR1/NR2B IgG antibody-positive patients showed more catatonia (P = 0.0042) and met Graus's criteria for diagnosis of anti-NMDAR encephalitis, but negative patients did not. Immunotherapy was effective for anti-NR1/NR2B IgG antibody-positive patients, and there was the weak relationship (R²â€¯= 0.318) between the anti-NR1/NR2B IgG antibody titer in the cerebrospinal fluid and the Brief Psychiatric Rating Scale score.

Anti-N-Methyl-D-Aspartate Receptor Encephalitis in Psychiatry.

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is a recently-discovered autoimmune disorder in which antibodies target NMDAR in the brain. The number of reported cases of anti-NMDAR encephalitis has increased rapidly. Anti-NMDAR encephalitis can be mistakenly diagnosed as psychiatric disorders because many patients present with prominent psychiatric symptoms and visit psychiatric institutions first. Thus, psychiatrists should cultivate a better understanding of anti-NMDAR encephalitis. In this review, we present the mechanisms, epidemiology, symptoms and clinical course, diagnostic tests, treatment and outcomes of patients with anti-NMDAR encephalitis. Furthermore, we discuss the diversity of clinical spectra of anti-NMDAR encephalitis, and demonstrate a differential diagnosis of psychiatric disease from the perspective of psychiatry.

Genome-Wide Association Study Detected Novel Susceptibility Genes for Schizophrenia and Shared Trans-Populations/Diseases Genetic Effect.

Genome-wide association studies (GWASs) have identified >100 susceptibility loci for schizophrenia (SCZ) and demonstrated that SCZ is a polygenic disorder determined by numerous genetic variants but with small effect size. We conducted a GWAS in the Japanese (JPN) population (a) to detect novel SCZ-susceptibility genes and (b) to examine the shared genetic risk of SCZ across (East Asian [EAS] and European [EUR]) populations and/or that of trans-diseases (SCZ, bipolar disorder [BD], and major depressive disorder [MDD]) within EAS and between EAS and EUR (trans-diseases/populations). Among the discovery GWAS subjects (JPN-SCZ GWAS: 1940 SCZ cases and 7408 controls) and replication dataset (4071 SCZ cases and 54479 controls), both comprising JPN populations, 3 novel susceptibility loci for SCZ were identified: SPHKAP (Pbest = 4.1 × 10-10), SLC38A3 (Pbest = 5.7 × 10-10), and CABP1-ACADS (Pbest = 9.8 × 10-9). Subsequent meta-analysis between our samples and those of the Psychiatric GWAS Consortium (PGC; EUR samples) and another study detected 12 additional susceptibility loci. Polygenic risk score (PRS) prediction revealed a shared genetic risk of SCZ across populations (Pbest = 4.0 × 10-11) and between SCZ and BD in the JPN population (P ~ 10-40); however, a lower variance-explained was noted between JPN-SCZ GWAS and PGC-BD or MDD within/across populations. Genetic correlation analysis supported the PRS results; the genetic correlation between JPN-SCZ and PGC-SCZ was ρ = 0.58, whereas a similar/lower correlation was observed between the trans-diseases (JPN-SCZ vs JPN-BD/EAS-MDD, rg = 0.56/0.29) or trans-diseases/populations (JPN-SCZ vs PGC-BD/MDD, ρ = 0.38/0.12). In conclusion, (a) Fifteen novel loci are possible susceptibility genes for SCZ and (b) SCZ "risk" effect is shared with other psychiatric disorders even across populations.

Assessment of a glyoxalase I frameshift variant, p.P122fs, in Japanese patients with schizophrenia.

Enhanced carbonyl stress has been observed in a subgroup of patients with schizophrenia. Glyoxalase I, which is encoded by GLO1, is an enzyme that protects against carbonyl stress. In this study, we focused on the association between rare genetic variants of GLO1 and schizophrenia. First, we identified one heterozygous frameshift variant, p.P122fs, in 370 Japanese schizophrenia cases with allele frequencies of up to 1% by exon-targeted mutation screening of GLO1. We then performed an association analysis on 1282 cases and 1764 controls with this variant. The variant was found in three cases and eight controls. There was no statistically significant association between p.P122fs in GLO1 and schizophrenia (P=0.25). This frameshift variant in GLO1 might occur at near-polymorphic frequencies in the Japanese population, although further investigations using larger samples and biological analyses are needed to exclude the possibility of a low-penetrance genetic risk associated with this variant.

Effects of the antipsychotics haloperidol, clozapine, and aripiprazole on the dendritic spine.

Three types of antipsychotics, typical (e.g. haloperidol), atypical (e.g. clozapine), and dopamine partial agonist (e.g. aripiprazole), are administered for treatment of schizophrenia. These antipsychotics have different efficacy and side-effect profiles. We investigated whether aripiprazole, clozapine, and haloperidol differentially regulate the dendritic spine through the AKT-GSK-3 beta cascade. Dissociated cortical neurons from Sprague-Dawley rats were prepared and cultured for 28 days. Aripiprazole, clozapine, or haloperidol was administered to the rat cortical neurons. The levels of PSD95 protein and AKT-GSK-3 beta cascade-related proteins were investigated by Western blot. The number of spines and PSD95 puncta were investigated by immunofluorescence cell staining. Aripiprazole (1 µM or 10 µM) and clozapine (1 µM) increased the levels of PSD95 protein, the number of spines, phosphorylated Akt Thr308 and Ser473, and phosphorylated GSK-3 beta Ser9. On the other hand, haloperidol (1 µM or 10 µM) or an inappropriate concentration of clozapine (10 µM) decreased them. A GSK inhibitor also increased the levels of PSD-95 protein and caused the same morphology. Aripiprazole, clozapine, and haloperidol differentially regulate the dendritic spine, and this effect may occur through the AKT-GSK-3 beta cascade. Selection and appropriate dose of these antipsychotics may be important for the protection of dendritic spines in patients with schizophrenia.