Tsuyoshi Kitajima

Fujita Health University, Nagoya, Aichi, Japan

Are you Tsuyoshi Kitajima?

Claim your profile

Publications (98)353.45 Total impact

  • Psychiatry and Clinical Neurosciences 02/2014; 68(2):167. · 2.04 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A sleep diary is often employed for diagnosing and treating hypersomnia. However, its reliability needs to be evaluated because overlooked chronic sleep insufficiency could be misdiagnosed as narcolepsy. In this study, we compared simultaneous sleep measurements using a sleep diary and by actigraphy in patients visiting our sleep clinic for the first time with complaints of excessive daytime sleepiness. Of the 28 patients enrolled, 24 complied with both these requirements. In this population, the results obtained using a sleep diary tended to estimate a statistically significant earlier sleep onset time and longer total sleep time than those via actigraphy. For total sleep time, this tendency was more prominent in patients with a higher Epworth Sleepiness Scale score. In 5 of the 24 (20.8%) patients, the sleep diary records indicated >6 h of total sleep time while the actigraphy records indicated <6 h of total sleep time, with a discrepancy of >1 h. These results suggested that sleep insufficiency in hypersomnia patients may be overlooked when their sleep time is assessed using only a sleep diary in the initial phase of the diagnostic procedure, and the simultaneous use of actigraphy may be preferable in this assessment.
    Sleep and Biological Rhythms 04/2013; 11(2). · 1.05 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Disturbances of the circadian rhythm are involved in the pathophysiology of bipolar disorder (BD), schizophrenia (SCZ) and major depressive disorder (MDD). Specifically, because clock gene dysfunction is good candidate for enhancing the susceptibility to these psychiatric disorders, we selected two circadian rhythm-related genes (CSNK1D and CSNK1E) and investigated genetic associations of the genes with these three disorders. None of the SNPs showed a significant association with MDD, but a SNP (rs2075984) in CSNK1E and SNP (rs6502097) in CSNK1D were associated with SCZ (P=0.0091, uncorrected) and BD (P=0.030, uncorrected), respectively. To confirm these findings, we analyzed an independent dataset (maximum N=3815) but found a lack of association (P=0.63 for rs2075984 and P=0.61 for rs6502097). The final meta-analysis showed no association between these SNPs with SCZ (P=0.21) and BD (P=0.53). These results do not support that genetic variation in CSNK1D and CSNK1E is a susceptibility factor for major psychiatric disorders in the Japanese population.
    Neuroscience Letters 09/2012; 529(1):66-9. · 2.03 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: BACKGROUND: Tetrahydrobiopterin (BH4) plays an important role in the biosynthesis of serotonin, melatonin and catecholamines, all of which are implicated in the pathophysiology of mood disorders (MDs), including major depressive disorder (MDD) and bipolar disorder (BP). Production of BH4 is regulated by GTP cyclohydrolase transcription and activity. Thus, we considered the GTP cyclohydrolase gene (GCH1) to be a good candidate gene in the pathophysiology of MDs and of the serotonin selective reuptake inhibitors (SSRIs) response in MDD, and conducted a case-control study utilizing three SNPs (rs8007267, rs3783641 and rs841) and moderate sample sizes (405 MDD patients, including 262 patients treated by SSRIs, 1022 BP patients and 1805 controls). METHOD: A multiple logistic regression analysis was carried out to compare the frequencies of each SNP genotype for the target phenotype across patients and controls in several genetic models, while adjusting for possible confounding factors. A clinical response was defined as a decrease of more than 50% from the baseline score on the Structured Interview Guide for Hamilton Rating Scale for Depression (SIGH-D) within 8 weeks, and clinical remission as a SIGH-D score of less than 7 at 8 weeks. RESULT: No associations between three SNPs in GCH1 and MDD or BP were observed; however, GCH1 was associated with SSRI therapeutic response in MDD in all the marker's haplotype analysis (Global P value=0.0379). CONCLUSIONS: Results suggest that GCH1 may predict response to SSRI in MDD in the Japanese population. Nevertheless, a replication study using larger samples may be required for conclusive results, since our sample size was small.
    Journal of affective disorders 07/2012; · 3.76 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Several lines of evidence suggest that genetic alterations in serotonin 6 (5-HT6) receptors might be associated with the pathophysiology of schizophrenia. We sought to assess the relationship between genotype alterations in 5-HT6 receptors and schizophrenia both in a case-control study and a meta-analysis. We conducted an association study of the 5-HT6 receptor gene (HTR6) in Japanese patients with schizophrenia (n = 836) and controls (n = 857). Five tagging single-nucleotide polymorphisms (SNPs), including rs1805054 (C267T) in HTR6, were selected. In addition, we carried out a meta-analysis between rs1805054, which has been examined in other studies, and schizophrenia, searching PubMed through August 2011. There were no significant associations between the tagging SNPs in HTR6 and schizophrenia in any of the genotype models in both the simple and the multiple logistic regression analyses correcting for potential confounds. Similarly, no significant association was found in the all-marker haplotype multiple logistic regression analysis (p = 0.491). Moreover, in the meta-analysis of rs1805054, drawing data from five studies, including our own (schizophrenia patients = 1366, controls = 1376), rs1805054 was also not associated with schizophrenia. Our results indicate that tagging SNPs in HTR6 may not play a role in the pathophysiology of schizophrenia.
    Human Psychopharmacology Clinical and Experimental 01/2012; 27(1):63-9. · 2.10 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Patients with schizophrenia frequently exhibit behavioral abnormalities associated with its pathological symptoms. Therefore, a quantitative evaluation of behavioral dynamics could contribute to objective diagnoses of schizophrenia. However, such an approach has not been fully established because of the absence of quantitative biobehavioral measures. Recently, we studied the dynamical properties of locomotor activity, specifically how resting and active periods are interwoven in daily life. We discovered universal statistical laws ("behavioral organization") and their alterations in patients with major depressive disorder. In this study, we evaluated behavioral organization of schizophrenic patients (n = 19) and healthy subjects (n = 11) using locomotor activity data, acquired by actigraphy, to investigate whether the laws could provide objective and quantitative measures for a possible diagnosis and assessment of symptoms. Specifically, we evaluated the cumulative distributions of resting and active periods, defined as the periods with physical activity counts successively below and above a predefined threshold, respectively. Here we report alterations in the laws governing resting and active periods; resting periods obeyed a power-law cumulative distribution with significantly lower parameter values (power-law scaling exponents), whereas active periods followed a stretched exponential distribution with significantly lower parameter values (stretching exponents), in patients. Our findings indicate enhanced persistency of both lower and higher locomotor activity periods in patients with schizophrenia, probably reflecting schizophrenic pathophysiology.
    PLoS ONE 01/2012; 7(8):e43539. · 3.53 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The clock gene (CLOCK) is considered to be a good candidate gene for the pathophysiology of mood disorders, including bipolar disorder (BP) and major depressive disorder (MDD). rs1801260 (T3111C) has been detected at position 3111 in the CLOCK mRNA 3' untranslated region, and was reported to be associated with a substantial delay in preferred timing for activity and sleep in a human study. As for function, rs1801260 has been speculated to affect mRNA. Therefore, the authors investigated the association between the three tagging single-nucleotide polymorphisms (SNPs) (rs3736544, rs1801260, and rs3749474) in CLOCK and risk of BP (n=867) and MDD (n=139) compared to controls (n=889) in the Japanese population. In addition, we also performed an updated meta-analysis of nine published, genetic association studies investigating the relationship between rs1801260 and mood disorder risk, comprising 3321 mood disorders cases and 3574 controls. We did not detect any associations between tagging SNPs in CLOCK and BP or MDD in the allele, genotype, or haplotype analysis (global p(BP)=.605 and global p(MDD)=.211). Moreover, rs1801260 was also not associated with BP, MDD, or any mood disorders in the meta-analysis. In conclusion, these data suggest that CLOCK does not play a major role in the pathophysiology of mood disorders.
    Chronobiology International 11/2011; 28(9):825-33. · 4.35 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: We previously showed that the sirtuin 1 gene (SIRT1 gene), one of the clock genes, was associated with schizophrenia in a Japanese patient population. Because the symptoms of methamphetamine (METH)-induced psychosis are similar to those of paranoid type schizophrenia and because not every METH user develops psychosis, it is conceivable that METH-induced psychosis and schizophrenia have common susceptibility genes. Therefore, we conducted an analysis of the association of SIRT1 gene with METH-induced psychosis, hypothesizing a significant relationship. This paper presents a case-control study of the SIRT1 gene in 515 Japanese individuals (197 with METH-induced psychosis and 318 age-matched and sex-matched controls) with four tagging single nucleotide polymorphisms (rs12778366, rs2273773, rs4746720, and rs10997875), selected a priori using the HapMap database. rs10997875 (located in the 3' flanking region) was associated with METH-induced psychosis (unadjusted p(genotype)  = 0.0203). However, these results became non-significant after Bonferroni correction (corrected p(genotype)  = 0.0812). In the all-marker haplotype analysis, the SIRT1 gene was not associated with METH-induced psychosis (p = 0.146). Our findings suggest that SIRT1 gene does not contribute to the development of METH-induced psychosis in the Japanese population. However, a replication study using larger samples should be conducted to obtain conclusive results.
    Human Psychopharmacology Clinical and Experimental 08/2011; 26(7):445-50. · 2.10 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Recently, we detected that the prokineticin 2 receptor gene was associated with not only major depressive disorder (MDD) but also methamphetamine dependence. Therefore, it is possible that mood disorders and drug addiction have shared susceptibility genes. The translin-associated factor X gene (TSNAX)/disrupted-in-schizophrenia-1 gene (DISC1) has been associated with psychiatric disorders, including schizophrenia, MDD and bipolar disorder. TSNAX is located immediately upstream of DISC1 and has been shown to undergo intergenic splicing with DISC1. Based on this evidence, we hypothesized that TSNAX might be a good candidate gene for methamphetamine dependence. We conducted a case-control study of Japanese individuals (215 with methamphetamine dependence and 318 age- and sex-matched controls) with three tagging SNPs (rs1630250, rs766288 and rs6662926) selected by HapMap database. rs1630250 was associated in males with methamphetamine dependence in the allele analysis (P-value: 0.0253). However, these results did not remain significant after Bonferroni correction to adjust for multiple comparisons (corrected P-value: 0.152). Our findings suggest that TSNAX does not play a role in methamphetamine dependence in the Japanese population. A replication study using larger samples needs to be conducted to obtain conclusive results.
    Progress in Neuro-Psychopharmacology and Biological Psychiatry 06/2011; 35(7):1618-22. · 3.55 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Several investigations have reported that abnormalities in circadian rhythms might be related to the pathophysiology of major depressive disorder (MDD) and the therapeutic response to selective serotonin reuptake inhibitors (SSRIs). Recently, ubiquitin-specific peptidase 46 (USP46), a new molecule related to the circadian clock system, has been described. We conducted a case control study between seven tagging SNPs (rs10517263, rs17675844, rs6554557, rs12646800, rs2244291, rs10034164, rs346005) in the USP46 gene, MDD, and the SSRI therapeutic response in MDD in the Japanese population. We recruited 432 MDD patients (202 males and 230 females) and 792 healthy controls (319 males and 473 females). Two hundred sixty-one of 432 MDD patients were treated with SSRIs (fluvoxamine, sertraline or paroxetine). We detected an association between the USP46 gene and MDD in a haplotype analysis (rs2244291-rs10034164-rs346005 and rs12646800-rs2244291-rs10034164-rs346005). However, we did not find any association between the USP46 gene and SSRI response or remission in MDD in the Japanese population. A replication study using larger samples may be required for conclusive results, since our sample size was small. Our results suggest that the USP46 gene might play a role in the pathophysiology of MDD in the Japanese population.
    Journal of affective disorders 06/2011; 133(1-2):150-7. · 3.76 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Several investigations suggested abnormalities in circadian rhythms are related to the pathophysiology of psychiatric disorders, including drug addiction. Recently, orphan nuclear receptor rev-erb alpha and glycogen synthase kinase-3 β (GSK-3β) were shown to be important circadian components. In addition, the orphan nuclear receptor rev-erb alpha is a key negative feedback regulator of the circadian clock. These evidences indicate that rev-erb alpha gene (NR1D1) is a good candidate gene for the pathogenesis of methamphetamine dependence. To evaluate the association between NR1D1 and methamphetamine dependence, we conducted a case-control study of Japanese samples (215 methamphetamine dependence and 232 controls) with three tagging SNPs selected by HapMap database. Written informed consent was obtained from each subject. This study was approved by the ethics committees at Fujita Health University, Nagoya University Graduate School of Medicine and each participating member of the Institute of the Japanese Genetics Initiative for Drug Abuse (JGIDA). We did not detect an association between NR1D1 and Japanese methamphetamine dependence patients in allele/genotype-wise analysis, or the haplotype analysis. Our findings suggest that NR1D1 does not play a major role in the pathophysiology of methamphetamine dependence in the Japanese population.
    DNA research: an international journal for rapid publication of reports on genes and genomes 03/2011; 9(1):129-32. · 1.73 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Endothelial nitric oxide synthase (NOS3) is one of the enzymes influencing nitric oxide (NO) function in the human brain. NO is a gaseous neurotransmitter that is involved in a variety of mechanisms in the central nervous system, such as N-methyl-D-aspartate receptor activation and oxidative stress. The evidence from animal pharmacological studies and postmortem studies supports an association between NO and psychotic disorders. Methamphetamine (METH) use disorder is a known psychotic disorder, and we therefore conducted a gene-based case-control study between tagging single nucleotide polymorphisms (SNPs) (rs2070744, rs1799983) in NOS3 and METH-induced psychosis in Japanese subjects (183 with METH-induced psychosis and 267 controls). Written informed consent was obtained from each subject. No significant association was found between any tagging SNP in NOS3 and METH-induced psychosis in the allele/genotype-wise or haplotype-wise analyses. In conclusion, we suggest that NOS3 might not contribute to the risk of METH-induced psychosis in the Japanese population.
    DNA research: an international journal for rapid publication of reports on genes and genomes 03/2011; 9(1):151-4. · 1.73 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Several investigations have suggested that abnormalities in glutamate neural transmission play a role in the pathophysiology of psychiatric disorders, including schizophrenia. The metabotropic glutamate 3 receptor (mGluR3) gene was reported to be associated with schizophrenia, and paranoid type schizophrenia has symptoms that are similar to those of methamphetamine-induced psychosis. This suggests that mGluR3 gene (GRM3) is a good candidate gene for the pathogenesis of methamphetamine-induced psychosis. To evaluate the association between GRM3 and methamphetamine-induced psychosis, we conducted a case-control study of Japanese samples (181 methamphetamine-induced psychosis and 232 controls). We selected one functional SNP (rs6465084), reported to be associated with prefrontal brain functioning, for an association analysis. Written informed consent was obtained from each subject. This study was approved by the ethics committees at Fujita Health University, Nagoya University Graduate School of Medicine and each participating member of the Institute of the Japanese Genetics Initiative for Drug Abuse (JGIDA). We did not detect an association between rs6465084 in GRM3 and Japanese methamphetamine-induced psychosis. Our findings suggest that rs6465084 in GRM3 does not play a major role in the pathophysiology of methamphetamine-induced psychosis in the Japanese population. However, because we did not perform an association analysis based on linkage disequilibrium (LD) or a mutation scan of GRM3, a replication study using a larger sample and based on LD may be required for conclusive results.
    DNA research: an international journal for rapid publication of reports on genes and genomes 03/2011; 9(1):160-2. · 1.73 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Disruption of circadian rhythms may be involved in the pathophysiology of psychiatric disorders, including drug addiction. Recently, we detected the significant association between prokineticin 2 receptor gene (PROKR2) and Japanese methamphetamine dependence patients. Also, prokineticin 2 (PK2) gene deficient mice showed reduced physiological and behavioral parameters, including circadian locomotor activity, circulating glucocorticoid, glucose levels and the expression of peripheral clock genes compared with WT mice. These evidences indicate that PK2 gene (PROK2) is a good candidate gene for the pathogenesis of methamphetamine dependence. To evaluate the association between PROK2 and methamphetamine dependence, we conducted a case-control study of Japanese samples (215 methamphetamine dependence and 232 controls) with four tagging SNPs selected by HapMap database. The age and sex of the control subjects did not differ from those of the methamphetamine dependence patients. Written informed consent was obtained from each subject. This study was approved by the ethics committees at Fujita Health University, Nagoya University Graduate School of Medicine and each participating member of the Institute of the Japanese Genetics Initiative for Drug Abuse (JGIDA). We did not detect an association between PROK2 and Japanese methamphetamine dependence patients in allele/genotype-wise analysis, or the haplotype analysis. Our findings suggest that PROK2 does not play a major role in the pathophysiology of methamphetamine dependence in the Japanese population.
    DNA research: an international journal for rapid publication of reports on genes and genomes 03/2011; 9(1):133-6. · 1.73 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The neuronal nitric oxide synthase gene (NOS1) is located at 12q24, a susceptibility region for schizophrenia, and produces nitric oxide (NO). NO has been reported to play important roles as a gaseous neurotransmitter in brain. NO is a second messenger for the N-methyl-D aspartate (NMDA) receptor and is related to the dopaminergic system. Because the symptomatology of methamphetamine (METH) use disorder patients with psychosis is similar to that of patients with schizophrenia, NOS1 is a good candidate gene for METH-induced psychosis. Therefore, we conducted a case-control association study between NOS1 and METH-induced psychosis with Japanese subjects (183 with METH-induced psychosis patients and 519 controls). We selected seven SNPs (rs41279104, rs3782221, rs3782219, rs561712, rs3782206, rs6490121, rs2682826) in NOS1 from previous reports. Written informed consent was obtained from each subject. This study was approved by the Ethics Committee at Fujita Health University School of Medicine and each participating institute of the Japanese Genetics Initiative for Drug Abuse (JGIDA). No significant association was found between NOS1 and METH-induced psychosis in the allele/genotype-wise or haplotype-wise analyses. In conclusion, we suggest that NOS1 might not contribute to the risk of METH-induced psychosis in the Japanese population.
    DNA research: an international journal for rapid publication of reports on genes and genomes 03/2011; 9(1):155-9. · 1.73 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Several investigations have reported associations between serotonin 1A (5-HT1A) receptor and major psychiatric disorders, such as schizophrenia and bipolar disorder (BP), making the 5-HT1A receptor gene (HTR1A) a good candidate gene for the pathophysiology of schizophrenia and BP. To evaluate the association between HTR1A and schizophrenia and BP, we conducted a case-control study of Japanese population samples with two single- nucleotide polymorphisms (SNPs), including rs6295 (C-1019G) in HTR1A. In addition, we conducted a meta-analysis of rs6295, which has been examined in other studies. Using one functional single- nucleotide polymorphism (SNP; rs6295) and one tagging SNP (rs878567), we conducted a genetic association analysis of case-control samples (857 schizophrenic patients, 1028 BP patients and 1810 controls) in the Japanese population. Two association studies for schizophrenia and three association studies for BP, including this study, met our criteria for the meta-analysis of rs6295. We found an association between HTR1A and Japanese BP in a haplotype-wise analysis, the significance of which remained after Bonferroni correction. In addition, we detected an association between rs6295 and BP in the meta-analysis (fixed model: P(Z)=0.000400). However, we did not detect an association between HTR1A and schizophrenia in the allele/genotype-wise, haplotype-wise or meta-analysis. HTR1A may play an important role in the pathophysiology of BP, but not schizophrenia in the Japanese population. In the meta-analysis, rs6295 in HTR1A was associated with BP patients.
    Psychiatry Research 01/2011; 185(1-2):20-6. · 2.68 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Altered serotonergic neural transmission is hypothesized to be a susceptibility factor for psychotic disorders such as schizophrenia. The serotonin 6 (5-HT6) receptor is therapeutically targeted by several second generation antipsychotics, such as clozapine and olanzapine, and d-amphetamine-induced hyperactivity in rats is corrected with the use of a selective 5-HT6 receptor antagonist. In addition, the disrupted prepulse inhibition induced by d-amphetamine or phencyclidine was restored by 5-HT6 receptor antagonist in an animal study using rats. These animal models were considered to reflect the positive symptoms of schizophrenia, and the above evidence suggests that altered 5-HT6 receptors are involved in the pathophysiology of psychotic disorders. The symptoms of methamphetamine (METH)-induced psychosis are similar to those of paranoid type schizophrenia. Therefore, we conducted an analysis of the association of the 5-HT6 gene (HTR6) with METH-induced psychosis. Using five tagging SNPs (rs6693503, rs1805054, rs4912138, rs3790757 and rs9659997), we conducted a genetic association analysis of case-control samples (197 METH-induced psychosis patients and 337 controls) in the Japanese population. The age and sex of the control subjects did not differ from those of the methamphetamine dependence patients. rs6693503 was associated with METH-induced psychosis patients in the allele/genotype-wise analysis. Moreover, this association remained significant after Bonferroni correction. In the haplotype-wise analysis, we detected an association between two markers (rs6693503 and rs1805054) and three markers (rs6693503, rs1805054 and rs4912138) in HTR6 and METH-induced psychosis patients, respectively. HTR6 may play an important role in the pathophysiology of METH-induced psychosis in the Japanese population.
    Drug and alcohol dependence 01/2011; 113(1):1-7. · 3.60 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Several lines of evidence suggest that alterations in circadian rhythms might be associated with the pathophysiology of psychiatric disorders such as schizophrenia and bipolar disorder (BP). A recent study reported that SIRT1 is a molecule that plays an important role in the circadian clock system. Therefore, to evaluate the association among the SIRT1 gene, schizophrenia and BP, we conducted a case-control study of Japanese population samples (1158 schizophrenia patients, 1008 BP patients and 2127 controls) with four tagging SNPs (rs12778366, rs2273773, rs4746720 and rs10997875) in the SIRT1 gene. Marker-trait association analysis was used to evaluate the allele and the genotype association with the χ(2) test, and haplotype association analysis was evaluated with a likelihood ratio test. We showed an association between rs4746720 in the SIRT1 gene and schizophrenia in the allele and the genotype analysis. However, the significance of these associations did not survive after Bonferroni's correction for multiple testing. On the other hand, the SIRT1 gene was associated with Japanese schizophrenia in a haplotype-wise analysis (global P(all markers) = 4.89 × 10(-15)). Also, four tagging SNPs in the SIRT1 gene were not associated with BP. In conclusion, the SIRT1 gene may play an important role in the pathophysiology of schizophrenia in the Japanese population.
    Genes Brain and Behavior 10/2010; 10(3):257-63. · 3.60 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Many patients with drug addiction are reported to have comorbid mood disorders. One of the suggested pathophysiological mechanisms for mood disorders is disruption of circadian rhythms. Several animal studies have shown that methamphetamine altered the expression of circadian clock molecules in the brain. Therefore, it is possible that mood disorders and drug addiction have common susceptibility genes. Recently, we reported that the prokineticin 2 receptor gene (PROKR2) was associated with mood disorders including major depressive disorder and bipolar disorder in the Japanese population. In the present study, therefore, we conducted an association analysis of tagging SNPs in PROKR2 with Japanese methamphetamine dependence patients. Using five tagging SNPs in PROKR2, we conducted a genetic association analysis of case-control samples (199 methamphetamine dependence patients and 337 healthy controls). The age and sex of the control subjects did not differ from those of the methamphetamine dependence patients. We detected a significant association between PROKR2 and methamphetamine dependence patients in allele/genotype-wise and haplotype-wise analysis. Our results suggest that PROKR2 may play a role in the pathophysiology of methamphetamine dependence in the Japanese population. However, because we did not perform a mutation scan of PROKR2, a replication study using a larger sample may be required for conclusive results.
    Progress in Neuro-Psychopharmacology and Biological Psychiatry 08/2010; 34(6):1033-6. · 3.55 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Several investigations have suggested that alterations in serotonin 6 (5-HT6) receptors might be associated with the pathophysiology of major depressive disorder (MDD), and that 5-HT6 receptors might be a therapeutic target for serotonin selective reuptake inhibitor (SSRI) in MDD. To evaluate the association between HTR6 and the efficacy of SSRI treatment in Japanese MDD patients, we conducted a case-control study in a Japanese population sample. We selected five tagging SNPs (rs6693503, rs1805054, rs4912138, rs3790757 and rs9659997), and performed an association analysis of HTR6 and the efficacy of SSRI treatment in 260 MDD patients. We did not detect an association between tagging SNPs in HTR6 and the therapeutic response to SSRI in MDD in allele/genotype or haplotype analysis. HTR6 may not play an important role in the pathophysiology of SSRI response in the Japanese population. Because our sample was relatively small, statistical errors were possible in the results of our association analyses. To overcome these limitations, a replication study using a larger sample may be required for conclusive results.
    Human Psychopharmacology Clinical and Experimental 08/2010; 25(6):481-6. · 2.10 Impact Factor

Publication Stats

1k Citations
353.45 Total Impact Points

Institutions

  • 2002–2013
    • Fujita Health University
      • Department of Psychiatry
      Nagoya, Aichi, Japan
  • 2009
    • Cardiff University
      • Department of Psychological Medicine and Neurology
      Cardiff, WLS, United Kingdom
  • 2006
    • Osaka City University
      Ōsaka, Ōsaka, Japan
  • 2005
    • Nagoya University
      • Division of Psychiatry
      Nagoya-shi, Aichi-ken, Japan
  • 2001–2003
    • Akita University Hospital
      Akita, Akita, Japan