Publications by authors named "Atsuhiro Miyazawa"
Aim: The spread of the novel coronavirus infection (coronavirus disease 2019 [COVID-19]) has caused behavioral changes and mental illness in patients and their attendants during its early phase. The present study aimed to examine the association between precautionary behaviors against COVID-19 and psychosocial factors in outpatients with pre-existing disease and their attendants.
Methods: We conducted a cross-sectional paper-based questionnaire survey in Chiba University Hospital on 1019 patients and 513 attendants, and a web-based questionnaire survey in Japan on 3981 individuals from the general population.
Article Synopsis
- Most genetic studies have struggled to identify specific genetic factors distinguishing treatment-resistant schizophrenia (TRS) patients from those who respond to treatment, but evidence suggests a difference in dopamine levels between the two groups.
- A genetic analysis involving 435 TRS patients, 539 non-TRS patients, and 489 healthy controls revealed distinct genotype distributions related to dopamine-related genes, indicating TRS patients had a higher proportion of the A allele of rs3756450.
- The findings imply that certain genetic variants affecting dopamine levels may play a role in determining patients' responses to antipsychotic medications, potentially aiding in the classification of TRS versus non-TRS individuals.
Background: Although numerous studies reported some changes of cortical silent period (CSP), an indicator of gamma-aminobutyric acid (GABA) function in central nervous system, in schizophrenia patients, it has been unknown how the disease stage and antipsychotic medication affect CSP values.
Methods: The present study conducted a systematic review of previous literature comparing CSP between schizophrenia patients and healthy subjects, and then performed meta-analysis on the effects of (1) the disease stage and (2) antipsychotics on CSP.
Results: (1) In the comparison of the disease stage comprising a total of 17 reports, there was no significant difference in CSP between patients under drug-naïve first-episode psychoses and healthy controls, or between patients with antipsychotic medication and healthy controls.
Background: GABAergic system dysfunction has been implicated in the etiology of schizophrenia and of cognitive impairments in particular. Patients with treatment-resistant schizophrenia (TRS) generally suffer from profound cognitive impairments in addition to severe positive symptoms, suggesting that GABA system dysfunction could be involved more closely in patients with TRS.
Methods And Results: In the present study, exome sequencing was conducted on fourteen TRS patients, whereby four SNPs were identified on GAD1, GABBR1 and GABBR2 genes.
The projection from dopaminergic neurons to gamma-aminobutyric acid (GABA) interneurons in the prefrontal cortex is involved in the etiology of schizophrenia. The impact of interacting effects between dopamine signals and the expression of GABA on the clinical phenotypes of schizophrenia has not been studied. Since these interactions could be closely involved in prefrontal cortex functions, patients with specific alleles of these relevant molecules (which lead to lower or vulnerable genetic functions) may develop treatment-refractory symptoms.
View Article and Find Full Text PDFObjectives: Although clozapine exhibited high efficacy for treating the symptoms of patients with treatment-resistant schizophrenia (TRS), its precise action mechanisms have not been fully understood. Recently, accumulating evidence has suggested the presence of abnormalities in the gamma-aminobutyric acid (GABA) systems in patients with schizophrenia, and the potential effects of clozapine on GABA receptors have gained a great deal of attention.
Experimental Designs: In the present study, the cortical silent period (CSP), an electrophysiological parameter of GABA function via GABA receptors, was measured using with the transcranial magnetic stimulation in patients with schizophrenia and healthy control subjects.