Publications by authors named "Jun-Ichi Iga"

The genetic architecture of white matter lesions (WMLs) in Asian populations has not been well-characterized. Here, we performed a genome-wide association study (GWAS) to identify loci associated with the WML volume. Brain MRI and DNA samples were collected from 9479 participants in the Japan Prospective Studies Collaboration for Aging and Dementia (JPSC-AD).

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Background: The main features of Axenfeld-Rieger Syndrome (ARS) are ocular, auditory, neurological, and morphological brain abnormalities. Mutations in forkhead box protein C1 (FOXC1) are among the responsible genes causing ARS, but neuropsychiatric features have rarely been reported. The case of an ARS patient (a 77-year-old man) with delusions of jealousy and impairment of working memory, in addition to the main clinical features, glaucoma and leukoencephalopathy, is presented.

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Aim: Constipation is one of the most common adverse effects in schizophrenia treatment, and it can sometimes cause severe gastrointestinal disease. However, the results of association studies between constipation and psychotropic medications in patients with schizophrenia are inconsistent. Therefore, we investigated the characteristics of psychotropic and laxative prescriptions at discharge in patients with schizophrenia to clarify the association between psychotropics and constipation.

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The frequency of behavioral and psychological symptoms of dementia (BPSD) is high, and it is a challenge to elucidate its neural substrates underlying their development. In recent years, many findings have been reported on the relationship between BPSD and brain volume in dementia patients. However, the results are not fully conclusive.

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  • * Out of 241 participants, over half (55.2%) were identified as having insomnia, exhibiting significantly worse scores in mental health assessments compared to those who slept well.
  • * The study found that specific sleep hygiene practices, particularly the recommendations from the Japanese Government, can impact insomnia, suggesting that clinicians can enhance treatment by applying effective stimulus control techniques.
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  • * Higher levels of hemoglobin A (HbA) and glycated albumin (GA), along with lower insulin secretion (measured by HOMA-β), were linked to smaller hippocampal volumes.
  • * The results suggest that managing blood sugar levels and insulin can help prevent reductions in hippocampal size, which may be important for reducing the risk of dementia.
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  • The study analyzed the effectiveness of three antipsychotic medications—aripiprazole, blonanserin, and paliperidone—over a 104-week period for patients with schizophrenia as part of the Japan Useful Medication Program for Schizophrenia (JUMPs).
  • A total of 251 patients were treated, with similar treatment discontinuation rates across all medications, and positive improvements in quality of life and symptom scores were noted over time.
  • The findings indicate that while treatment results were comparable, continuing with these medications can lead to improved remission rates and overall quality of life for patients.
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Aims: To determine the prevalence and impact of emotional blunting (EB) in patients with major depressive disorder (MDD) in Japan, and identify treatment needs for EB using patients' perceptions and attitudes.

Methods: Eligible patients in Japan (aged 18-59 years) who reported a diagnosis of MDD and antidepressant medication use for >3 months were eligible to complete an online survey. The primary outcome was the prevalence of EB, self-reported using a validated screening question.

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Aim: To assess the association between plasma amyloid β (Aβ) 42/40, phosphorylated tau (p-τ)181, glial fibrillary acidic protein (GFAP), or neurofilament light chain (NfL) and the risk of dementia and to determine whether these plasma biomarkers could improve the ability to predict incident dementia in a general older population.

Methods: A total of 1346 Japanese community-dwelling individuals aged ≥65 years without dementia were followed prospectively for 5.0 years.

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In recent years, the association between neuroinflammatory markers and dementia, especially Alzheimer's disease (AD), has attracted much attention. However, the evidence for the relationship between serum-hs-CRP and dementia including AD are inconsistent. Therefore, the relationships of serum high-sensitivity CRP (hs-CRP) with dementia including AD and with regions of interest of brain MRI were investigated.

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No study has shown the relationship between alanine-glyoxylate aminotransferase 2 (AGXT2) single nucleotide polymorphisms (SNPs) and depressive symptoms. The present case-control study examined this relationship in Japanese adults. Cases and control participants were selected from those who participated in the baseline survey of the Aidai Cohort Study, which is an ongoing cohort study.

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Antipsychotic treatment is vital for patients with schizophrenia even in the perinatal period, but the impact at the molecular biological level on offspring is unclear. The aim of the present study was to investigate the effects of intraperitoneal haloperidol injection to pregnant mice on glutamate and GABA receptors in the brain of offspring mice. Eight-week-old pregnant mice were treated with either intraperitoneal haloperidol or normal saline injection, and their offspring were defined as F1 mice.

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Aim: This study aims to examine the real-world effectiveness of education regarding clinical guidelines for psychiatric disorders using 'the Effectiveness of guidelines for dissemination and education in psychiatric treatment (EGUIDE)' project.

Methods: The EGUIDE project is a nationwide prospective implementation study of two clinical practice guidelines, i.e.

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Background: Enlarged perivascular spaces (EPVS) of the brain may be involved in dementia, such as Alzheimer's disease and cerebral small vessel disease (CSVD). Hypertension has been reported to be a risk factor for dementia and CSVD, but the association between blood pressure (BP) and perivascular spaces is still unclear. The aim of this study was to determine the association between BP and EPVS volumes and to examine the interactions of relevant factors.

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  • Decreased gait speed in older adults is linked to higher prevalence of mild cognitive impairment (MCI), but the relationships differ by gender and age.
  • A study of over 8,200 Japanese participants aged 65 and older revealed that males consistently showed higher MCI prevalence than females, and the odds of MCI increased with slower gait speeds.
  • The findings indicate that while gait speed is a potential screening tool for MCI, its implications may vary based on age and gender, emphasizing the need for tailored approaches in clinical assessments.
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Background: The number of patients with cognitive disorders is rapidly increasing in the world, becoming not only a medical problem, but also a social problem. There have been many reports that various factors are associated with cognitive dysfunction, but the factors have not yet been fully identified. This was a community-based complete enumeration study which aimed to identify risk and protective factors for dementia.

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  • Social isolation, defined as low frequency of social contact, has been linked to increased risks of dementia and depressive symptoms, prompting researchers to explore its potential effects on brain volume and health in older adults.
  • A study involving 8,896 dementia-free Japanese individuals aged 65 and older utilized brain MRI scans and health examinations to evaluate the relationship between frequency of social contact and various brain region volumes.
  • Results indicated that individuals with less social contact had significantly lower total brain volume and increased white matter lesions, suggesting that social interaction may play a critical role in brain health and that depressive symptoms could mediate this relationship.
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Background: Polypharmacy of additional psychotropics alongside the main treatment drug (antipsychotics in schizophrenia and antidepressants in major depressive disorder) is common in Japan. Our goal is to align psychotropic prescription in Japan with international standards, while reducing the differences between facilities. To achieve this goal, we aimed to compare prescriptions at the time of hospital admission and discharge.

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Background: Although several guidelines recommend monotherapy with antipsychotics for the treatment of schizophrenia, patients who receive long-acting injectable antipsychotics (LAIs) are frequently treated with oral antipsychotics (OAPs). In the present study, we investigated the detailed use of psychotropic medications among patients throughout Japan with schizophrenia who received LAIs or OAPs.

Methods: The present study used data from the project for the Effectiveness of Guidelines for Dissemination and Education in psychiatric treatment from 94 facilities in Japan.

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Background: We explored the gene expression levels in the brain of 3xTg-AD model mice to elucidate the molecular pathological changes from the early to end stages of Alzheimer's disease (AD).

Objective: We re-analyzed our previously published microarray data obtained from the hippocampus of 3xTg-AD model mice at 12 and 52 weeks of age.

Methods: Functional annotation and network analyses of the up- and downregulated differentially expressed genes (DEGs) in mice aged 12 to 52 weeks were performed.

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Background: The onset of schizophrenia is associated with both genetic and environmental risks during brain development. Environmental factors during pregnancy can represent risk factors for schizophrenia, and we have previously reported that several microRNA and mRNA expression changes in fetal brains exposed to haloperidol during pregnancy may be related to the onset of this disease. This study aimed to replicate that research and focused on apoptotic-related gene expression changes.

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  • * A study with 8,630 Japanese participants aged 65 and older evaluated the connection between urinary albumin-creatinine ratio (UACR), estimated glomerular filtration rate (eGFR), and various brain volume metrics using MRI scans.
  • * Results indicated that high UACR levels were associated with smaller brain volume ratios and more WMLV, while lower eGFR was associated with brain volume loss but not significantly linked to WMLV; the study’s cross-sectional nature
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Only 50% of patients with depression respond to the first antidepressant drug administered. Thus, biomarkers for prediction of antidepressant responses are needed, as predicting which patients will not respond to antidepressants can optimize selection of alternative therapies. We aimed to identify biomarkers that could predict antidepressant responsiveness using a novel data-driven approach based on statistical pattern recognition.

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Background: Autism spectrum disorder (ASD), is a neurodevelopmental disorder that is known to have a high degree of heritability. Diagnosis of ASD is difficult because of the high heterogeneity of the clinical symptoms. MicroRNAs (miRNAs) can potentially be diagnostic biomarkers for ASD, and several studies have shown the relationship between miRNAs and ASD pathogenesis.

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Background: Several guidelines recommend monotherapy in pharmacotherapy for schizophrenia and major depressive disorder. The content of regular prescriptions has been reported in several studies, but not enough research has been conducted on the content of pharmacotherapy, including pro re nata (PRN) medications. The purpose of this study was to evaluate the content of pharmacotherapy, including PRN medications, and to clarify the relationship with regular prescriptions.

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