記述言語：英語   出版者・発行元：Journal of Korean Medical Science  

Background: This study aimed to compare the symptom structures of hikikomori in Korea and Japan through a network analysis approach, addressing the scarcity of comparative research and elucidating potential cross-cultural differences in its manifestation. Methods: Data were derived from the Research on Asian Psychotropic Prescription Patterns, Phase 3 (REAP-AD3) study, involving psychiatric patients in Korea and Japan. Social withdrawal symptoms were assessed using the one-month version of the 25-item Hikikomori Questionnaire (HQ-25M). Network analyses were performed to characterize symptom interconnections and centrality in both cohorts. Differences in network structure, edge strength, and global strength were evaluated using the network comparison test (NCT). Results: The NCT indicated no statistically significant differences in network structure invariance between Korean and Japanese patients. Notably, the most frequently endorsed symptom among Korean psychiatric patients was “no one to discuss important matters with,” whereas for Japanese psychiatric patients it was “difficulty enjoying social situations.” Conclusion: Although overall network structures were largely comparable, the findings suggest subtle distinctions in the organization of social withdrawal symptoms between Korean and Japanese psychiatric patients. These differences underscore the importance of developing culturally tailored preventive and therapeutic strategies for hikikomori in these populations.

DOI： 10.3346/jkms.2026.41.e139

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記述言語：英語   出版者・発行元：Dialogues in Clinical Neuroscience  

Introduction: Depression includes different phenotypes. Modern-type depression (MTD) is a gateway disorder to pathological social withdrawal, known as hikikomori. Adverse childhood experiences (ACEs) are also important aetiologies of depression. Recently, immune imbalance has been proposed as a biological basis of depression. We hypothesised that peripheral immunological characteristics may be involved in subtyping of depression. Methods: 21 patients with major depressive disorder (MDD) and 24 healthy controls (HC) were recruited. Peripheral blood mononuclear cells (PBMCs) were examined for surface antigens by flow cytometry. Participants were administered psychological scales such as Patient Health Questionnaire (PHQ)-9, Modern-Type Depression Trait Scale (TACS-22), Hikikomori Questionnaire (HQ-25), Child Abuse and Trauma Scale (CATS). Results: MDD group showed significantly higher percentage of B cells than HC group (p = 0.032). MDD group presented a negative correlation between: PHQ-9 and CD8 T effector memory cells (r= –0.639, p = 0.002), TACS-22 and monocytes (r= –0.459, p = 0.036), HQ-25 and NK T cells (r= –0.638, p = 0.004), CATS and Intermediate monocytes (r= –0.594, p = 0.009). Conclusions: MTD traits, hikikomori tendencies, and ACEs were correlated with specific characteristics of peripheral immune cells. Our results suggest that immune imbalance influences the diverse presentations of depression. Further validation is warranted by large-scale prospective studies.

DOI： 10.1080/19585969.2025.2452842

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記述言語：英語   出版者・発行元：Psychiatry and Clinical Neurosciences  

DOI： 10.1111/pcn.13837

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記述言語：英語   出版者・発行元：Journal of Affective Disorders  

Background: In the 1990s, the concepts of hikikomori and modern-type depression (MTD) emerged in Japan. Hikikomori is a condition of social avoidance or isolation, characterized by staying at home and being physically isolated for at least six months. MTD is characterized by depressive symptoms—mainly in stressful work or school situations during adolescence and early adulthood—which tend to rapidly reduce or disappear after leaving the stressful situation. We hypothesized that childhood maltreatment can form MTD traits that lead to hikikomori. Methods: As a first step, we conducted a multigroup path analysis between childhood maltreatment, MTD traits, and physical isolation in the hikikomori group. This study utilized the nine-item Patient Health Questionnaire (PHQ-9), Home Environment Questionnaire (HEQ), 22-item Tarumi Modern-Type Depressive Trait Scale (TACS-22), 25-item Hikikomori Questionnaire (HQ-25), and Hamilton Depression Rating Scale (HDRS). The HQ-25 contains three factors: physical isolation, lack of socialization, and lack of emotional support. Results: The hikikomori group included 92 patients and the control group comprised 137 healthy individuals. All total and subscale scores of PHQ-9, HEQ, TACS-22, HQ-25, and HDRS were significantly higher in the hikikomori group than in the control group. The risk model of childhood maltreatment for physical isolation via MTD traits obtained good fit with a goodness-of-fit index of.982. Limitations: The study's limitations were its sample selection bias, cross-sectional design, and use of self-report scales. Conclusions: Our findings support the hypothesis that childhood maltreatment is an important risk factor for hikikomori via MTD traits.

DOI： 10.1016/j.jad.2024.05.094

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記述言語：英語   出版者・発行元：Psychiatry and Clinical Neurosciences  

DOI： 10.1111/pcn.13564

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記述言語：日本語  

記述言語：日本語  

記述言語：英語   出版者・発行元：John Wiley & Sons Australia, Ltd  

掲載種別：会議報告等  

DOI： 10.1093/ijnp/pyae059.511

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出版者・発行元：Clinical and Experimental Neuroimmunology  

Recent studies have highlighted the importance of microglia as key immunomodulators in a variety of neuropsychiatric diseases. Postmortem brain analysis and positron emission tomography are representative research approaches to assess microglial activation in human patients and this research has revealed microglial activation in the brains of patients with various neuropsychiatric disorders. However, only limited aspects of microglial activation can be assessed with these methods. To overcome the technical and ethical limitations of collecting human-derived microglia in brain biopsies, we first developed a method to generate directly induced microglia-like (iMG) cells from fresh human peripheral blood monocytes in 2014. These iMG cells can be used to perform dynamic morphological and molecular analyses regarding phagocytic capacity and cytokine release following stress stimulation at the cellular level. Patient-derived iMG cells can potentially serve as an important surrogate marker for estimating microglial activation in the human brain, and may provide previously unknown insights into the dynamic pathophysiology of microglia in patients with neuropsychiatric disorders. Thus, the iMG-based technology could be used as a valuable reverse translational tool and provide new insights into the dynamic molecular pathophysiology of microglia in a wide variety of psychiatric and physical disorders.

DOI： 10.1111/cen3.12815

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記述言語：英語   出版者・発行元：(一社)日本神経免疫学会  

記述言語：英語   出版者・発行元：Journal of Visualized Experiments  

Recent investigations employing animal models have highlighted the significance of microglia as crucial immunological modulators in various neuropsychiatric and physical diseases. Postmortem brain analysis and positron emission tomography imaging are representative research methods that evaluate microglial activation in human patients; the findings have revealed the activation of microglia in the brains of patients presenting with various neuropsychiatric disorders and chronic pain. Nonetheless, the aforementioned technique merely facilitates the assessment of limited aspects of microglial activation. In lieu of brain biopsy and the induced pluripotent stem cell technique, we initially devised a technique to generate directly induced microglia-like (iMG) cells from freshly derived human peripheral blood monocytes by supplementing them with granulocyte-macrophage colony-stimulating factor and interleukin 34 for 2 weeks. These iMG cells can be employed to perform dynamic morphological and molecular-level analyses concerning phagocytic capacity and cytokine releases following cellular-level stress stimulation. Recently, comprehensive transcriptome analysis has been used to verify the similarity between human iMG cells and brain primary microglia. The patient-derived iMG cells may serve as key surrogate markers for predicting microglial activation in human brains and have aided in the unveiling of previously unknown dynamic pathophysiology of microglia in patients with Nasu-Hakola disease, fibromyalgia, bipolar disorder, and Moyamoya disease. Therefore, the iMG-based technique serves as a valuable reverse-translational tool and provides novel insights into elucidating dynamic the molecular pathophysiology of microglia in a variety of mental and physical diseases.

DOI： 10.3791/66819

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