Mashima, Yuki

写真a

Affiliation

School of Medicine, Department of Neuropsychiatry ( Shinanomachi )

Position

Project Assistant Professor (Non-tenured)/Project Research Associate (Non-tenured)/Project Instructor (Non-tenured)
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Papers 【 Display / hide 】

  • Post-conclusion belief inflexibility bias assessed by a modified beads task in schizophrenia

    Mashima Y., Shinagawa K., Suzuki H., Onaya M., Nakane J., Uchida H., Mimura M., Umeda S., Koreki A.

    Schizophrenia Research 296   121 - 129 2026.10

    ISSN  09209964

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    Background A key defining feature of delusions in psychiatric practice is their incorrigibility, reflecting marked cognitive inflexibility. Among cognitive biases in schizophrenia, belief inflexibility explains the maintenance of delusions, whereas the jumping-to-conclusions bias relates to delusion formation. However, belief inflexibility once a conclusion has been reached, which may more directly reflect the maintenance process following formation, has not yet been investigated. Methods Twenty-nine patients with schizophrenia (SZ) and twenty-eight healthy controls (HC) completed a modified beads task that separated phases reflecting cognitive processes involved in delusion formation (Phase 1) and maintenance (Phase 2). In Phase 1, following the classical beads task paradigm, beads were drawn one by one from one of two jars. After each draw, participants were asked whether they could state a conclusion about which jar was being used. Phase 1 ended once a conclusion was reached with sufficient confidence. In Phase 2, bead drawing continued, and participants judged whether to withdraw their Phase 1 conclusion. In some trials, subsequent bead colours contradicted the conclusion, favouring withdrawal. Results In Phase 1, the number of beads required to reach a conclusion did not differ significantly between groups. In Phase 2, however, SZ required significantly more beads to withdraw their prior conclusion, with this delayed withdrawal being particularly evident in those with delusion-predominant symptoms. Conclusions These findings are consistent with the notion that post-conclusion belief inflexibility contributes to the maintenance of delusions, providing empirical support for models of delusion maintenance distinct from those addressing delusion formation.

  • Psychiatric Symptoms Associated with Corticosteroid Use: A Systematic Review and Meta-analysis

    Kusudo K., Mashima Y., Yasuda H., Iyo T., Takeuchi H.

    CNS Drugs 40 ( 8 ) 1101 - 1147 2026.08

    ISSN  11727047

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    Background and Objective: Corticosteroids (CSs) are widely prescribed but can induce psychiatric adverse effects (depressive, manic, psychotic, and anxiety symptoms). This systematic review aimed to quantify the association between CS use and psychiatric symptoms and to explore potential moderators across clinical contexts. Methods: We conducted a Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)-guided systematic review and meta-analysis. MEDLINE and Embase were searched through 10 October, 2025, and 19 hand-searched records were also screened. We included observational studies in medical CS users and excluded sex steroids, neonatal exposure, prescription-only outcomes, purely objective outcomes, sleep/cognition/delirium-focused studies, CS deficiency, withdrawal, and studies confounded by co-medications; randomized controlled trials were excluded by design. Two reviewers screened studies, extracted data, and assessed risk of bias with the Newcastle-Ottawa Scale. Certainty of evidence for each pooled outcome was additionally evaluated using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. Pairwise meta-analyses pooled standardized mean differences and odds ratios using random-effects models; I<sup>2</sup> quantified heterogeneity. The acute phase was operationally defined as ≤ 8 weeks after CS initiation. An exploratory meta-regression across six studies (seven groups) examined dose, duration, cumulative dose, age, and sex. Results: Seventy-three studies (total N = 3,759,659) were included (22 cross-sectional, 31 cohort, 12 pre-post, 2 case-control, 2 registry, and 4 prospective patient-as-own-control investigations comparing outcomes during on-CS vs off-CS periods). Compared with non-users, CS use was associated with higher depressive symptom scores (standardized mean difference = 0.92, 95% confidence interval [CI] 0.40–1.45; p < 0.001; I<sup>2</sup> = 89%; seven studies; n = 1403; eight groups). During the operationally defined acute phase (≤ 8 weeks after CS initiation), manic symptoms were more frequent than depressive symptoms (six studies; n = 1086; odds ratio = 2.42, 95% CI 1.48–3.97; p < 0.001; I<sup>2</sup> = 0%). A single-arm meta-analysis estimated psychotic symptoms in 2.4% of CS users (95% CI 0.76–7.26; six studies; n = 1206). Anxiety showed no significant association with CS use (standardized mean difference = 0.13, 95% CI − 0.24 to 0.51; p = 0.26; I<sup>2</sup> = 7%; three studies; n = 1251). Overall study quality (Newcastle-Ottawa Scale) was generally moderate to high, whereas certainty of evidence according to GRADE was generally low to very low across pooled outcomes. The exploratory meta-regression suggested that higher daily dose and older age were associated with greater depressive severity; by contrast, cumulative dose, treatment duration, and sex showed no significant associations, and these moderator findings remain exploratory. Conclusions: Corticosteroid use is associated with more severe depressive symptoms, and manic symptoms may predominate during acute treatment; psychotic reactions are uncommon. Dose and age may modulate depressive severity, but these moderator findings should be interpreted cautiously. Routine monitoring for mood and psychotic changes, especially early after initiation and in higher-dose or older patients, is warranted.

  • Family History and Solar Insolation in Bipolar I Disorder

    Bauer M., Glenn T., Achtyes E.D., Alda M., Agaoglu E., Altınbaş K., Andreassen O.A., Angelopoulos E., Ardau R., Aydin M., Ayhan Y., Baethge C., Bauer R., Baune B.T., Balaban C., Becerra-Palars C., Behere A.P., Belete H., Belete T., Okawa Belizario G., Bellivier F., Belmaker R.H., Benedetti F., Berk M., Bersudsky Y., Bicakci , Birabwa-Oketcho H., Bjella T.D., Brady C., Cabrera J., Cappucciati M., Paredes Castro A.M., Chen W., Cheung E.Y.W., Chiesa S., Chanopoulou M., Crowe M., Cuomo A., Dallaspezia S., Desai P., Dodd S., Etain B., Fagiolini A., Fellendorf F.T., Ferensztajn-Rochowiak E., Fiedorowicz J.G., Fountoulakis K.N., Frye M.A., Geoffroy P.A., Gitlin M.J., Gonzalez-Pinto A., Gottlieb J.F., Grof P., Haarman B.C.M., Harima H., Hasse-Sousa M., Henry C., Hoffding L., Houenou J., Imbesi M., Isometsä E.T., Ivkovic M., Janno S., Johnsen S., Kapczinski F., Karakatsoulis G.N., Kardell M., Kessing L.V., Kim S.J., König B., Kot T.L., Koval M., Kunz M., Lafer B., Landén M., Larsen E.R., Licht R.W., Ludwig V.M., Lopez-Jaramillo C., Mackenzie A., Madsen H.Ø., Madsen S.A.K.A., Mahadevan J., Mahardika A., Mahfoudh K., Manchia M., Marsh W., Martinez-Cengotitabengoa M., Martini J., Martiny K., Mashima Y., McLoughlin D.M., Meesters A.N.R., Meesters Y., Melle I., Meza-Urzúa F., Michaelis E., Mikolas P., Mok Y.M., Monteith S.

    Acta Psychiatrica Scandinavica 153 ( 4 ) 270 - 278 2026.04

    ISSN  0001690X

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    Background: Sunlight has profound impacts on physical and mental health, beyond vision, including effects on circadian rhythms, alertness, mood, and sleep. A family history of any mood disorders is strongly associated with psychiatric disorders including bipolar disorder. The purpose of this study was to evaluate the association between a family history of any mood disorder in patients with bipolar I disorder and solar insolation at varied international onset locations. Methods: Data for this analysis were available from 5842 patients with a diagnosis of bipolar I disorder obtained at 83 collection sites in both hemispheres. This included 4752 patients from 71 collection sites in the northern hemisphere and 1090 patients from 12 collection sites in the southern hemisphere. Patient data variables were obtained from records or interviews. Solar insolation data were obtained from The National Aeronautics and Space Administration (NASA) Power database for each onset location, and the ratio of the mean monthly minimum/mean monthly maximum solar insolation was calculated. Typically, the ratio is largest near the equator (little yearly change in solar insolation) and smallest near the poles (large yearly change in solar insolation). Results: A significant relationship was found between a family history of any mood disorder, the ratio of the mean monthly minimum/mean monthly maximum solar insolation, and gender. The odds of a family history of mood disorder increased as patient location nears the poles and decreased near the equator. Female gender also increased the odds of having a family history of a mood disorder. Conclusions: This study highlighted the association between family history, solar insolation, and gender in international patients with bipolar I disorder. Given the profound effects of sunlight on human health, the family of patients with bipolar disorder who live in the same location with the same solar insolation, and especially females, may be at increased risk for a mood disorder.

  • Impact of Mindfulness-Based Cognitive Therapy on Trajectory of Mood States in Patients with Chronic Pain: A Retrospective Observational Study of Within-Session Evaluations

    Tanaka C., Shinohara Y., Takaoka S., Kawate M., Mashima Y., Hoshino R., Fujisawa D., Kosugi S., Wakaizumi K.

    Journal of Clinical Medicine 15 ( 5 )  2026.03

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    Background/Objectives: Mindfulness-Based Cognitive Therapy (MBCT) is a well-documented treatment option for chronic pain. However, few studies have examined the emotional state experienced by participants with chronic pain during the sessions. This study aimed to assess the trajectory of mood experiences in an MBCT program and evaluate the effect on temporal mood state. Methods: The Temporary Mood Scale (TMS) was used to assess vigor, fatigue, anger-hostility, depression-dejection, tension-anxiety, and confusion before and after each MBCT session from July 2018 to May 2019. A total of 33 patients with chronic pain who attended the MBCT program were included in the study. A mixed-effect model was used to identify single-session and overall effects on each mood state. Pearson’s correlation analysis was used to examine the associations between changes in the six mood states and baseline conditions, including pain-related factors. Results: The mixed-effect model identified significant improvements in single-session effects on all mood states (p < 0.001). Significant overall effects were identified on vigor (p < 0.01), depression-dejection (p < 0.01), tension-anxiety (p < 0.001), and confusion (p < 0.05) states throughout the sessions. Moreover, participants with higher tension-anxiety at baseline showed significantly greater improvements in anger-hostility (p < 0.05), depression-dejection (p < 0.01), tension-anxiety (p < 0.05), and confusion (p < 0.01). Conclusions: Individual sessions and the overall MBCT program significantly improved the mood states of patients with chronic pain. Patients with higher tension-anxiety are likely to be effective treatment targets for MBCT programs.

  • Diverse tau pathologies in late-life mood disorders revealed by PET and autopsy assays

    Kurose S., Moriguchi S., Kubota M., Tagai K., Momota Y., Ichihashi M., Sano Y., Endo H., Hirata K., Kataoka Y., Goto R., Mashima Y., Yamamoto Y., Suzuki H., Nakajima S., Mizutani M., Sano T., Kawamura K., Zhang M.R., Tatebe H., Tokuda T., Onaya M., Mimura M., Sahara N., Takahashi H., Uchida H., Takao M., Meyer J.H., Higuchi M., Takahata K.

    Alzheimer S and Dementia 21 ( 6 )  2025.06

    ISSN  15525260

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    INTRODUCTION: Late-life mood disorders (LLMDs) may represent prodromal manifestations of neurodegenerative dementia; however, the neuropathological basis of LLMDs, including depression and bipolar disorder, remains unclear. We aimed to investigate the involvement of Alzheimer's disease (AD) and non-AD tau pathologies in LLMD participants. METHODS: Fifty-two LLMD participants and 47 age- and sex-matched healthy controls (HCs) underwent tau and amyloid beta (Aβ) positron emission tomography (PET) imaging using <sup>18</sup>F-florzolotau and <sup>11</sup>C-Pittsburgh compound B. Additionally, we conducted a clinicopathological correlation analysis in 208 autopsy cases, including various neurodegenerative diseases. RESULTS: LLMD participants were more likely to be tau PET and Aβ PET positive than HCs. The PET results were supported by the post mortem results that showed a higher likelihood of diverse tauopathies in patients with late-life mania or depression than those without. DISCUSSION: Our PET and autopsy assays suggest that AD and diverse non-AD tau pathologies might underlie the neuropathological basis of some LLMD cases. Highlights: Late-life mood disorders (LLMDs) may represent prodromal states of dementia. The neuropathological basis of LLMDs remains unclear. LLMD subjects were highly likely to be tau positron emission tomography (PET) positive. Brain bank data supported our PET results. Alzheimer's disease (AD) and diverse non-AD tau pathologies can contribute to LLMDs.

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