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Aim Hypofunction of N-methyl-D-aspartate receptors (NMDAR) may contribute to the pathophysiology of schizophrenia (SCZ). Recently, the glycine cleavage system (GCS) was shown to affect NMDAR function in the brain. GCS functional defects cause nonketotic hyperglycinemia, the atypical phenotype of which presents psychiatric symptoms similar to SCZ. Here, we examined the involvement of GCS in SCZ. Methods First, to identify the rare variants and the exonic deletions, we resequenced all the coding exons and the splice sites of four GCS genes (GLDC, AMT, GCSH, and DLD) in 474 patients with SCZ and 475 controls and performed multiplex ligation-dependent probe amplification analysis in SCZ. Next, we performed metabolome analysis using plasma of patients harboring GCS variants (n = 5) and controls (n = 5) by capillary electrophoresis time-of-flight mass spectrometry. The correlation between plasma metabolites and Positive and Negative Syndrome Scale score was further examined. Results Possibly damaging variants were observed in SCZ: A203V, S801N in GLDC, near the atypical nonketotic hyperglycinemia causative mutations (A202V, A802V); G825D in GLDC, a potential neural tube defect causative mutation; and R253X in AMT. Marked elevation of plasma 5-oxoproline (pyroglutamic acid), aspartate, and glutamate, which might affect NMDAR function, was observed in patients harboring GCS variants. The aspartate level inversely correlated with negative symptoms (r = -0.942, P = 0.0166). Conclusion These results suggest that GCS rare variants possibly contribute to the pathophysiology of SCZ by affecting the negative symptoms through elevation of aspartate.

Hypofunction of N-methyl-D-aspartate receptors (NMDAR) may contribute to the pathophysiology of schizophrenia (SCZ). Recently, the glycine cleavage system (GCS) was shown to affect NMDAR function in the brain. GCS functional defects cause nonketotic hyperglycinemia, the atypical phenotype of which presents psychiatric symptoms similar to SCZ. Here, we examined the involvement of GCS in SCZ.First, to identify the rare variants and the exonic deletions, we resequenced all the coding exons and the splice sites of four GCS genes (GLDC, AMT, GCSH, and DLD) in 474 patients with SCZ and 475 controls and performed multiplex ligation-dependent probe amplification analysis in SCZ. Next, we performed metabolome analysis using plasma of patients harboring GCS variants (n = 5) and controls (n = 5) by capillary electrophoresis time-of-flight mass spectrometry. The correlation between plasma metabolites and Positive and Negative Syndrome Scale score was further examined.Possibly damaging variants were observed in SCZ: A203V, S801N in GLDC, near the atypical nonketotic hyperglycinemia causative mutations (A202V, A802V); G825D in GLDC, a potential neural tube defect causative mutation; and R253X in AMT. Marked elevation of plasma 5-oxoproline (pyroglutamic acid), aspartate, and glutamate, which might affect NMDAR function, was observed in patients harboring GCS variants. The aspartate level inversely correlated with negative symptoms (r = -0.942, P = 0.0166).These results suggest that GCS rare variants possibly contribute to the pathophysiology of SCZ by affecting the negative symptoms through elevation of aspartate.

Aim The present study examined the effect of irritable bowel syndrome (IBS), cognitive appraisal of IBS, and anxiety sensitivity on anticipatory anxiety (AA) and agoraphobia (AG) in patients with panic disorder (PD). Methods We examined 244 PD patients who completed a set of questionnaires that included the Rome II Modular Questionnaire to assess the presence of IBS, the Anxiety Sensitivity Index (ASI), the Cognitive Appraisal Rating Scale (CARS; assessing the cognitive appraisal of abdominal symptoms in four dimensions: commitment, appraisal of effect, appraisal of threat, and controllability), and items about the severity of AA and AG. The Mini International Neuropsychiatric Interview was used to diagnose AG and PD. Results After excluding individuals with possible organic gastrointestinal diseases by using ‘red flag items,’ valid data were obtained from 174 participants, including 110 PD patients without IBS (PD/IBS[–]) and 64 with IBS (PD/IBS[+]). The PD/IBS[+] group had higher AA and higher comorbidity with AG than the PD/IBS[–] group. In the PD/IBS[+] group, the controllability score of CARS was significantly correlated with AA and ASI. Multiple regression analysis showed a significant effect of ASI but not of controllability on AA in PD/IBS[+] subjects. Conclusion This study suggested that the presence of IBS may be related to agoraphobia and anticipatory anxiety in PD patients. Cognitive appraisal could be partly related to anticipatory anxiety in PD patients with IBS with anxiety sensitivity mediating this correlation.

Aims: Frequent onset of several mental disorders starts around undergraduate age for university students. Mental health check-ups of the new students might help provide them with useful supports for improving their mental health. However, few studies have examined the validity of the check-up methods. Methods: Whether the scores of a five-factor personality inventory (NEO-FFI) at matriculation predict the needs of mental care and treatment during the first year of the undergraduate course were examined in 8287 new students of a university in Tokyo. Results: Logistic regression showed that high neuroticism, low extraversion and high openness of NEO-FFI, majoring in literature/philosophy/ psychology and living out of home were associated with need for mental care/treatment, in addition to the previous use of mental care services. Conclusions: Personality inventory such as five-factor ones may be a useful supplemental tool for mental health check-up at matriculation to predict future needs of mental support in undergraduate university students. Students who smoke, live alone out of home and major in subjects such as philosophy might need to be more carefully supported than other students.

Environmental factors, in addition to genetic factors, may be related to the development of panic attack (PA) and panic disorder (PD). Previous studies suggested that there may be seasonal variation in the onset of PA/PD and possibly a higher prevalence of PA/PD in colder areas. Also observed were lactate-induced PA and elevated serum cholesterol in PD patients. These suggest that living environment and lifestyle, such as weather conditions, preference of food and physical exercise, might play a role in the occurrence of PA and PD. The present study explored the association of such candidate factors with the development of PA and PD in 4000 Japanese subjects, using a questionnaire. The subjects were recruited from the general population of Japan, using stratified random sampling. Logistic regression with stepwise selection of variables was employed for statistical analysis. Variables including "dislike of physical exercise", mostly in female subjects, and "living in areas with longer winter", in male subjects, were suggested for associations with PA and PD among the candidate factors. The result is preliminary but indicates that lifestyle such as like/dislike of physical exercise and environmental factors including weather conditions could play a partial role in the development of PA and PD. Further investigations are required before firm conclusions can be reached.

Corticotropin-releasing hormone (CRH) has been implicated in the pathophysiology of anxiety disorders and depression. Corticotropin-releasing hormone receptor 2 (CRHR2) is one of the receptors that mediate CRH signal. The purpose of the present study was to investigate the association between the CRHR2 gene and personality traits, evaluated using the Revised NEO Personality Inventory (NEO PI-R), in 243 healthy Japanese subjects. As a result, significant association was observed between the polymorphism in intron 2 (rs2267717) and Openness (P = 0.004, uncorrected, anova), while no relationship was observed concerning Neuroticism. The present result suggests an association between CRHR2 and the personality trait of Openness.

The present study examined the effect of irritable bowel syndrome (IBS), cognitive appraisal of IBS, and anxiety sensitivity on anticipatory anxiety (AA) and agoraphobia (AG) in patients with panic disorder (PD).We examined 244 PD patients who completed a set of questionnaires that included the Rome II Modular Questionnaire to assess the presence of IBS, the Anxiety Sensitivity Index (ASI), the Cognitive Appraisal Rating Scale (CARS; assessing the cognitive appraisal of abdominal symptoms in four dimensions: commitment, appraisal of effect, appraisal of threat, and controllability), and items about the severity of AA and AG. The Mini International Neuropsychiatric Interview was used to diagnose AG and PD.After excluding individuals with possible organic gastrointestinal diseases by using 'red flag items,' valid data were obtained from 174 participants, including 110 PD patients without IBS (PD/IBS[-]) and 64 with IBS (PD/IBS[+]). The PD/IBS[+] group had higher AA and higher comorbidity with AG than the PD/IBS[-] group. In the PD/IBS[+] group, the controllability score of CARS was significantly correlated with AA and ASI. Multiple regression analysis showed a significant effect of ASI but not of controllability on AA in PD/IBS[+] subjects.This study suggested that the presence of IBS may be related to agoraphobia and anticipatory anxiety in PD patients. Cognitive appraisal could be partly related to anticipatory anxiety in PD patients with IBS with anxiety sensitivity mediating this correlation.

Schizophrenia and bipolar disorder share some clinical features and linkage studies have shown that several loci are common. Recently, the authors found that the −116CG substitution in the promotor region of XBP1, a pivotal gene in endoplasmic reticulum (ER) stress response, causes the impairment of ER stress response, and that the −116C/C genotype is a protective factor; in other words the presence of the G allele increases the risk for bipolar disorder. The gene is located on 22q12.1, which is also linked with schizophrenia. The polymorphisms were investigated in 234 schizophrenic patients as compared with controls. Significant difference of genotype distribution was observed, which suggested that the −116C/C genotype is a protective factor for both of the major mental disorders.

THE CLOCK GENE 3111 C/T polymorphism has been reported to be associated with human diurnal preference and psychiatric disorders, including schizophrenia and bipolar disorder. Furthermore, specific personality traits may be correlated with psychiatric symptoms. Therefore, we hypothesized that the CLOCK gene could be a candidate for the personality-related gene and investigated the association between CLOCK and personality traits in Japanese healthy subjects. The research protocol was approved by the Ethics Committee of the Graduate School of Medicine, University of Tokyo. All participants provided written informed consent. All participants were unrelated Japanese subjects. The subjects consisted of 383 healthy volunteers (139 men and 244 women; mean age 35.4 11.2 years [mean SD]) recruited from the staff of several mental and general hospitals around Tokyo. We genotyped the CLOCK gene 3111C/T polymorphism (rs1801260) using the TaqMan assay (Applied Biosystems, Foster, CA, USA). Personality traits were evaluated by using the Revised NEO Personality Inventory (NEO PI-R). The associations between scores for the NEO PI-R factors and genotypes were statistically analyzed by ANCOVA with sex and age as covariates. The genotype distributions did not deviate significantly from Hardy–Weinberg equilibrium. Because the frequency of the homozygotes for the C allele of CLOCK was very low, we also compared scores for the NEO PI-R factors between T/T genotype and C allele carrier (C/T and C/C genotypes) groups. No significant difference in the scores for the NEO PI-R factors was observed among the three genotype groups or between T/T genotype and C allele carrier groups (Table 1). Our study did not provide evidence for the association between the CLOCK gene 3111 C/T polymorphism and personality traits in the Japanese population. REFERENCES