Tani, Hideaki



School of Medicine, Department of Neuropsychiatry (Shinanomachi)


Senior Assistant Professor (Non-tenured)/Assistant Professor (Non-tenured)


Papers 【 Display / hide

  • Effects of Discontinuation of Drugs Used for Augmentation Therapy on Treatment Outcomes in Depression: A Systematic Review and Meta-analysis

    Kato H., Koizumi T., Takeuchi H., Tani H., Mimura M., Uchida H.

    Pharmacopsychiatry (Pharmacopsychiatry)  54 ( 3 ) 106 - 116 2021.05

    ISSN  01763679

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    Introduction There has been no consensus on whether and how long add-on drugs for augmentation therapy should be continued in the treatment of depression. Methods Double-blind randomized controlled trials that examined the effects of discontinuation of drugs used for augmentation on treatment outcomes in patients with depression were identified. Meta-analyses were performed to compare rates of study withdrawal due to any reason, study-defined relapse, and adverse events between patients who continued augmentation therapy and those who discontinued it. Results Seven studies were included (n=841 for continuing augmentation therapy; n=831 for discontinuing augmentation therapy). The rate of study withdrawal due to any reason was not significantly different between the 2 groups (risk ratio [RR]=0.86, 95% confidence interval [CI]=0.69-1.08, p=0.20). Study withdrawal due to relapse was less frequent in the continuation group than in the discontinuation group (RR=0.61, 95% CI=0.40-0.92, p=0.02); however, this statistical significance disappeared when one study using esketamine as augmentation was excluded. Analysis of the data from 5 studies that included a stabilization period before randomization found less frequent relapse in the continuation group than in the discontinuation group (RR=0.47, 95% CI=0.36-0.60, p<0.01). This finding was repeated when the esketamine study was excluded. Discussion No firm conclusions could be drawn in light of the small number of studies included. Currently available evidence suggests that add-on drugs, other than esketamine, used for augmentation therapy for depression may be discontinued. This may not be the case for patients who are maintained with augmentation therapy after remission.

  • Factors associated with successful antipsychotic dose reduction in schizophrenia: a systematic review of prospective clinical trials and meta-analysis of randomized controlled trials

    Tani H., Takasu S., Uchida H., Suzuki T., Mimura M., Takeuchi H.

    Neuropsychopharmacology (Neuropsychopharmacology)  45 ( 5 ) 887 - 901 2020.04

    ISSN  0893133X

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    This systematic review and meta-analysis examined predictors of successful antipsychotic dose reduction in schizophrenia. Prospective clinical trials and randomized controlled trials (RCTs) investigating antipsychotic dose reduction in schizophrenia were selected for systematic review and meta-analysis, respectively. In total, 37 trials were identified. Only 8 studies focused on second-generation antipsychotics (SGAs); no studies investigated long-acting injectable SGAs. Of 24 studies evaluating relapse or symptom changes, 20 (83.3%) met the criteria for successful dose reduction. Factors associated with successful dose reduction were study duration < 1 year, age > 40 years, duration of illness > 10 years, and post-reduction chlorpromazine equivalent (CPZE) dose > 200 mg/day. Clinical deterioration was mostly re-stabilized by increasing the dose to the baseline level (N = 7/8, 87.5%). A meta-analysis of 18 RCTs revealed that relapse rate was significantly higher in the reduction group than the maintenance group (risk ratio [RR] = 1.96; 95% confidence interval [CI], 1.23–3.12), whereas neurocognition was significantly improved (standardized mean difference = 0.69; 95% CI, 0.25–1.12). A subgroup analysis indicated that only a post-reduction CPZE dose ≤ 200 mg/day was associated with an increased risk of relapse (RR = 2.79; 95% CI, 1.29–6.03). Thus, when reducing antipsychotic doses, clinicians should consider the long-term risk of relapse in younger patients with a relatively short illness duration and keep the final doses higher than CPZE 200 mg/day. Further studies, particularly those involving SGAs, are warranted to determine the optimal strategies for successful antipsychotic dose reduction in schizophrenia.

  • Visualization of AMPA receptors in living human brain with positron emission tomography

    Miyazaki T., Nakajima W., Hatano M., Shibata Y., Kuroki Y., Arisawa T., Serizawa A., Sano A., Kogami S., Yamanoue T., Kimura K., Hirata Y., Takada Y., Ishiwata Y., Sonoda M., Tokunaga M., Seki C., Nagai Y., Minamimoto T., Kawamura K., Zhang M.R., Ikegaya N., Iwasaki M., Kunii N., Kimura Y., Yamashita F., Taguri M., Tani H., Nagai N., Koizumi T., Nakajima S., Mimura M., Yuzaki M., Kato H., Higuchi M., Uchida H., Takahashi T.

    Nature Medicine (Nature Medicine)  26 ( 2 ) 281 - 288 2020.02

    ISSN  10788956

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    Although aberrations in the number and function of glutamate AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid) receptors are thought to underlie neuropsychiatric disorders, no methods are currently available for visualizing AMPA receptors in the living human brain. Here we developed a positron emission tomography (PET) tracer for AMPA receptors. A derivative of 4-[2-(phenylsulfonylamino)ethylthio]-2,6-difluoro-phenoxyacetamide radiolabeled with 11C ([11C]K-2) showed specific binding to AMPA receptors. Our clinical trial with healthy human participants confirmed reversible binding of [11C]K-2 in the brain according to Logan graphical analysis (UMIN000020975; study design: non-randomized, single arm; primary outcome: dynamics and distribution volumes of [11C]K-2 in the brain; secondary outcome: adverse events of [11C]K-2 during the 4–10 d following dosing; this trial met prespecified endpoints). In an exploratory clinical study including patients with epilepsy, we detected increased [11C]K-2 uptake in the epileptogenic focus of patients with mesial temporal lobe epilepsy, which was closely correlated with the local AMPA receptor protein distribution in surgical specimens from the same individuals (UMIN000025090; study design: non-randomized, single arm; primary outcome: correlation between [11C]K-2 uptake measured with PET before surgery and AMPA receptor protein density examined by biochemical study after surgery; secondary outcome: adverse events during the 7 d following PET scan; this trial met prespecified endpoints). Thus, [11C]K-2 is a potent PET tracer for AMPA receptors, potentially providing a tool to examine the involvement of AMPA receptors in neuropsychiatric disorders.

  • Drug attitude, insight, and patient’s knowledge about prescribed antipsychotics in schizophrenia: A cross-sectional survey

    Nagai N., Tani H., Yoshida K., Gerretsen P., Suzuki T., Ikai-Tani S., Mimura M., Uchida H.

    Neuropsychiatric Disease and Treatment (Neuropsychiatric Disease and Treatment)  16   781 - 787 2020

    ISSN  11766328

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    Introduction: While patients’ perspectives toward pharmacotherapy are expected to be directly influenced by their motivation and understanding of the treatment that they are currently receiving, no study has comprehensively investigated the impact of insight into illness and knowledge for the ongoing pharmacotherapy on the attitude towards drug treatment among patients with schizophrenia. Materials and Methods: One hundred forty-eight Japanese outpatients diagnosed with schizophrenia, according to the International Classification of Diseases 10th edition, were included (mean±SD age, 47.3±12.4 years; 90 men (60.8%)). Attitudes toward antipsychotic treatment and insight into illness were assessed with the Drug Attitude Inventory-10 (DAI-10) and the VAGUS, respectively. In addition, a multiple-choice questionnaire that was designed to examine patients’ knowledge about therapeutic effects, types, and implicated neurotransmitters of antipsychotic drugs they were receiving was utilized. Results: The mean±SD of DAI-10 score was 4.7±4.2. The multiple regression analysis found that lower Positive and Negative Syndrome Scale (PANSS) scores, higher VAGUS scores, and longer illness duration were significantly associated with higher DAI-10 scores (β=−0.226, P=0.009; β=0.250, P=0.008; β=0.203, P=0.034, respectively). There was a significant difference in the DAI-10 scores between the subjects who gave more accurate answers regarding the effects of their primary antipsychotic and those who did not (mean ±SD, 5.57±4.38 vs 4.13±4.04, P=0.043); however, this finding failed to survive the multiple regression analysis. Conclusion: Better insight into illness and treatment, lower illness severity, longer illness duration, and possibly greater knowledge about the therapeutic effects of medications may lead to better attitudes towards pharmacotherapy among patients with schizophrenia, which has an important implication for this typically chronic mental condition requiring long-term antipsychotic treatment to sustain stability.

  • Switching to antipsychotic monotherapy vs. staying on antipsychotic polypharmacy in schizophrenia: A systematic review and meta-analysis

    Matsui K., Tokumasu T., Takekita Y., Inada K., Kanazawa T., Kishimoto T., Takasu S., Tani H., Tarutani S., Hashimoto N., Yamada H., Yamanouchi Y., Takeuchi H.

    Schizophrenia Research (Schizophrenia Research)  209   50 - 57 2019.07

    ISSN  09209964

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    Background: While recent meta-analyses have reported the superiority of antipsychotic polypharmacy (APP) over antipsychotic monotherapy (APM) in schizophrenia, switching to APM can be beneficial in terms of side effects. To determine whether patients receiving APP should switch to APM or stay on APP, we conducted a systematic review and meta-analysis. Methods: Randomized controlled trials (RCTs) examining a switch from APP to APM vs. staying on APP were systematically selected from a previous meta-analysis comparing APP with APM in patients with schizophrenia. In addition, we conducted an updated systematic literature search using MEDLINE, Embase, and Cochrane Central Register of Controlled Trials. Data on study discontinuation, relapse, psychopathology, neurocognition, extrapyramidal symptoms, and body weight/body mass index (BMI) were extracted and synthesized. Results: A total of 6 RCTs involving 341 patients were included. All studies examined a switch from 2 antipsychotic agents to a single agent. Clozapine-treated patients were included in 3 studies. There was a significant difference in study discontinuation due to all causes in favor of staying on APP (N = 6, n = 341, RR = 2.28, 95% CI = 1.50–3.46, P < 0.001). There were no significant differences in relapse, any psychopathology, neurocognition, extrapyramidal symptoms, or body weight/BMI between the 2 groups. The quality of evidence was low to very low. Conclusions: The findings suggest that clinicians should closely monitor patient condition when switching to APM after receiving 2 antipsychotics. Given the low to very low overall quality of the evidence, the findings should be considered preliminary and inconclusive.

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  • 新たな治療法の開発に向けた治療抵抗性うつ病の神経基盤の解明:AMPA-PET研究


    MEXT,JSPS, Grant-in-Aid for Scientific Research, 若手研究, Principal investigator