The cell cycle-related genes as biomarkers for schizophrenia.

BACKGROUND: Recent studies suggest that genomic abnormalities such as single nucleotide polymorphisms (SNPs) and copy number variations (CNVs) may elevate the risk of schizophrenia. Such genomic abnormalities often occur during chromosomal DNA replication in the S phase of cell cycle. In addition, several studies showed that abnormal expressions of several cell cycle-related genes are associated with schizophrenia. Therefore, here we compared mRNA expression levels of cell cycle-related genes in peripheral blood cells between patients with schizophrenia and healthy controls. METHOD: mRNA expression levels of cell cycle-related genes in peripheral blood cells from patients with schizophrenia and healthy controls were measured with quantitative reverse transcription polymerase chain reaction (Q-RT-PCR). The discovery, replication and intervention studies with Q-RT-PCR were performed as follows: discovery (40 cases and 20 controls), replication (82 cases and 74 controls) and intervention (22 cases and 18 controls). RESULT: Nine genes were identified in the discovery and replication stages as schizophrenia-associated genes. Moreover, the combination of mRNA expression levels of CDK4, MCM7 and POLD4 was identified as a potential biomarker for schizophrenia with multivariate logistic regression analysis. The intervention stage revealed that the mRNA expression levels of these three genes were significantly decreased in the acute state of schizophrenia, and CDK4 was significantly recovered in the remission state of schizophrenia. CONCLUSION: The combination of mRNA expression levels of three cell cycle-related genes such as CDK4, MCM7 and POLD4 is expected to be a candidate for useful biomarkers for schizophrenia. Especially, the mRNA expression changes of CDK4 may be potential as both trait and state markers for schizophrenia.

Antipsychotic switching versus augmentation among early non-responders to risperidone or olanzapine in acute-phase schizophrenia.

PURPOSE: We examined whether augmentation with olanzapine would be superior to switching to olanzapine among early non-responders (ENRs) to risperidone, and whether augmentation with risperidone would be superior to switching to risperidone among ENRs to olanzapine. We performed a rater-blinded, randomized clinical trial at psychiatric emergency sites. Eligible patients were newly admitted patients with acute schizophrenia. ENRs to the initial antipsychotic (Clinical Global Impressions-Improvement Scale: ≥ 4 at 2 weeks) were allocated to receive either augmentation with or switching to the other antipsychotic (RIS+OLZ vs. RIS-OLZ; OLZ+RIS vs. OLZ-RIS) RESULTS: Sixty patients who completed 2 weeks of risperidone treatment were divided into 33 early responders (RIS-ER) and 27 ENRs (RIS+OLZ, n=14; RIS-OLZ, n=13). Although time to treatment discontinuation for any cause was significantly shorter in RIS+OLZ group (54.1 days [95% confidence interval, 41.3-67.0]) than in RIS-ER group (68.7 [61.2-76.2]; P=0.050), it was not significantly shorter in RIS-OLZ group (58.5 [43.1-73.9]) than in RIS-ER group (P=0.19). Sixty patients who completed 2 weeks of olanzapine treatment were divided into 36 early responders (OLZ-ER) and 24 ENRs (OLZ+RIS, n=11; OLZ-RIS, n=13). Although time to treatment discontinuation for any cause was significantly shorter in OLZ-RIS group (56.1days [40.7-71.5]) than in OLZ-ER group (74.9 [68.5-81.3]; P=0.008), it was not significantly shorter in OLZ+RIS group (64.6 [49.6-79.6]) than in OLZ-ER group (P=0.20). CONCLUSION: Despite the lack of pharmacokinetic investigation of dose adequacy in this study, it is possible that switching to olanzapine among ENRs to risperidone might have a small advantage over augmentation with olanzapine, while augmentation with risperidone might have a small advantage over switching to risperidone among ENRs to olanzapine. Further research is required before it would be appropriate to modify routine practice in the direction of these findings.

The possibility that requiring high-dose olanzapine cannot be explained by pharmacokinetics in the treatment of acute-phase schizophrenia.

We examined clinical characteristics including serum olanzapine concentrations for acute schizophrenia patients who required above conventional doses. We performed a rater-blinded, randomized clinical trial in 12 psychiatric emergency sites. Eligible patients were 18-64 years old and met diagnostic criteria for schizophrenia, acute schizophrenia-like psychotic disorder, or schizoaffective disorder. A total of 42 patients were randomly assigned by means of sealed envelopes to receive risperidone (3-12 mg/day; n=20) and olanzapine (10-40 mg/day; n=22), with follow-up at 8 weeks. The Negative score of the Positive and Negative Syndrome Scale was significantly higher in patients who required high doses than in patients who responded to conventional doses. Serum olanzapine concentrations at the time of oral 20mg/day could be obtained from 5 out of 7 patients who subsequently required high-dose olanzapine. All values were more than 30 ng/mL after 11-16 h from dosing to sample collection, and the mean value was 47.876 (S.D. 21.546) ng/mL. Such concentrations are appropriate with respect to a therapeutic range of 20-50 ng/mL. The present study has shown evidence that the reason for requiring high-dose olanzapine cannot be explained by pharmacokinetics in the treatment of acute-phase schizophrenia.