Kikuchi, Toshiaki



School of Medicine, Department of Neuropsychiatry (Shinanomachi)


Associate Professor


Papers 【 Display / hide

  • Association of electroconvulsive therapy-induced structural plasticity with clinical remission

    Takamiya A., Kishimoto T., Hirano J., Kikuchi T., Yamagata B., Mimura M.

    Progress in Neuro-Psychopharmacology and Biological Psychiatry (Progress in Neuro-Psychopharmacology and Biological Psychiatry)  110 2021.08

    ISSN  02785846

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    Background: Electroconvulsive therapy (ECT) is the most effective treatment for severe depression. Recent neuroimaging studies have consistently reported that ECT induces volume increases in widely distributed brain regions. However, it still remains unclear about ECT-induced volume changes associated with clinical improvement. Methods: Longitudinal assessments of structural magnetic resonance imaging were conducted in 48 participants. Twenty-seven elderly melancholic depressed individuals (mean 67.5 ± 8.1 years old; 19 female) were scanned before (TP1) and after (TP2) ECT. Twenty-one healthy controls were also scanned twice. Whole-brain gray matter volume (GMV) was analyzed via group (remitters, nonremitters, and controls) by time (TP1 and TP2) analysis of covariance to identify ECT-related GMV changes and GMV changes specific to remitters. Within-subject and between-subjects correlation analyses were conducted to investigate the associations between clinical improvement and GMV changes. Depressive symptoms were evaluated using the 17-item Hamilton Depression Rating Scale (HAM-D), and remission was defined as HAM-D total score ≤ 7. Results: Bilateral ECT increased GMV in multiple brain regions bilaterally regardless of clinical improvement. Remitters showed a larger GMV increase in the right-lateralized frontolimbic brain regions compared to nonremitters and healthy controls. GMV changes in the right hippocampus/amygdala and right middle frontal gyrus showed correlations with clinical improvement in within−/between-subjects correlation analyses. Conclusions: ECT-induced GMV increase in the right frontolimbic regions was associated with clinical remission.

  • Antipsychotic Polypharmacy Is Associated with Adverse Drug Events in Psychiatric Inpatients: The Japan Adverse Drug Events Study

    Ayani N., Morimoto T., Sakuma M., Kikuchi T., Watanabe K., Narumoto J.

    Journal of Clinical Psychopharmacology (Journal of Clinical Psychopharmacology)  41 ( 4 ) 397 - 402 2021.07

    ISSN  02710749

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    Background Antipsychotic (AP) polypharmacy (APP), the coprescription of more than 1 AP, is frequently practiced in psychiatric inpatients and is considered to be a risk factor for adverse drug events (ADEs). However, the association between APP and ADEs among psychiatric inpatients has not been well investigated. Methods The Japan Adverse Drug Events (JADE) study was a series of cohort studies conducted in several clinical settings. In particular, the JADE study for psychiatric inpatients was a retrospective cohort study of 448 psychiatric inpatients with a cumulative 22,733 patient-days. We investigated the relationship between APP, defined as a concurrent prescription of 2 or more APs and ADEs. We also assessed the relationship between potential risk factors for ADEs due to APs. Results Among the 448 patients included in this study, 106 patients (24%) had APP and the remaining 342 patients were prescribed 1 AP or none. Risperidone was the most frequent drug (25%, 109/442 AP prescriptions) used, and levomepromazine was most frequently prescribed as a concurrent medication with other APs (91%, 29/32). The median number of ADEs among the patients with APP was significantly higher than in those without APP (P = 0.001). Antipsychotic polypharmacy was a risk factor for the occurrence of first (adjusted hazard ratio, 1.54; 95% confidence interval, 1.15-2.04) and second (adjusted hazard ratio, 1.99; 95% confidence interval, 1.40-2.79) ADEs. Conclusions Antipsychotic polypharmacy was a risk factor for the occurrence of single and multiple ADEs. Antipsychotic polypharmacy should be conservatively and minimally practiced.

  • Does cognitive behavioral therapy for anxiety disorders assist the discontinuation of benzodiazepines among patients with anxiety disorders? A systematic review and meta-analysis

    Takeshima M., Otsubo T., Funada D., Murakami M., Usami T., Maeda Y., Yamamoto T., Matsumoto T., Shimane T., Aoki Y., Otowa T., Tani M., Yamanaka G., Sakai Y., Murao T., Inada K., Yamada H., Kikuchi T., Sasaki T., Watanabe N., Mishima K., Takaesu Y.

    Psychiatry and Clinical Neurosciences (Psychiatry and Clinical Neurosciences)  75 ( 4 ) 119 - 127 2021.04

    ISSN  13231316

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    Long-term use of benzodiazepines (BZD) is not recommended for the treatment of anxiety disorders. Cognitive behavioral therapy (CBT) is an effective treatment option for discontinuation of BZD in patients with anxiety disorders. This systematic review and meta-analysis sought to clarify whether CBT is effective for discontinuing BZD anxiolytics in patients with anxiety disorders. This study was preregistered with PROSPERO (registration number: CRD42019125263). A literature search of major electronic databases was conducted in December 2018. Three randomized controlled trials were included in this review, and meta-analyses were performed. The proportion of discontinuing BZD anxiolytics was significantly higher in the CBT plus gradual tapering group than in the gradual tapering alone group, both in the short term (3 months after allocation; number needed to treat: 3.2, 95% confidence interval [CI]: 2.1 to 7.1; risk ratio: 1.96, 95%CI: 1.29 to 2.98, P = 0.002, three studies) and long term (6 to 12 months after allocation; number needed to treat: 2.8, 95%CI: 1.9 to 5.3; risk ratio: 2.16, 95%CI: 1.41 to 3.32, P = 0.0004, three studies). CBT may be effective for discontinuing BZD anxiolytics, both in the short term and in the long term after the allocation. Further studies with larger sample sizes are necessary to draw definitive conclusions regarding the efficacy and safety of CBT for discontinuing BZD anxiolytics in patients with anxiety disorders.

  • Pharmacological Treatment of Schizophrenia: Japanese Expert Consensus

    Sakurai H., Yasui-Furukori N., Suzuki T., Uchida H., Baba H., Watanabe K., Inada K., Kikuchi Y.S., Kikuchi T., Katsuki A., Kishida I., Kato M.

    Pharmacopsychiatry (Pharmacopsychiatry)  54 ( 2 ) 60 - 67 2021.03

    ISSN  01763679

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    Introduction Conventional treatment guidelines of schizophrenia do not necessarily provide solutions on clinically important issues. Methods A total of 141 certified psychiatrists of the Japanese Society of Clinical Neuropsychopharmacology evaluated treatment options regarding 19 clinically relevant situations in the treatment of schizophrenia with a 9-point scale (1=disagree and 9=agree). Results First-line antipsychotics varied depending on predominant symptoms: risperidone (mean±standard deviation score, 7.9±1.4), olanzapine (7.5±1.6), and aripiprazole (6.9±1.9) were more likely selected for positive symptoms; aripiprazole (7.6±1.6) for negative symptoms; aripiprazole (7.3±1.9), olanzapine (7.2±1.9), and quetiapine (6.9±1.9) for depression and anxiety; and olanzapine (7.9±1.5) and risperidone (7.5±1.5) for excitement and aggression. While only aripiprazole was categorized as a first-line treatment for relapse prevention (7.6±1.0) in patients without noticeable symptoms, aripiprazole (8.0±1.6) and brexpiprazole (6.9±2.3) were categorized as such for social integration. First-line treatments in patients who are vulnerable to extrapyramidal symptoms include quetiapine (7.5±2.0) and aripiprazole (6.9±2.1). Discussion These clinical recommendations represent the expert consensus on the use of a particular antipsychotic medication for a particular situation, filling a current gap in the literature.

  • Estimated model of psychotropic polypharmacy for bipolar disorder: Analysis using patients' and practitioners' parameters in the MUSUBI study

    Adachi N., Azekawa T., Edagawa K., Goto E., Hongo S., Kato M., Katsumoto E., Kikuchi T., Kubota Y., Miki K., Nakagawa A., Tsuboi T., Ueda H., Watanabe K., Watanabe Y., Yasui-Furukori N., Yoshimura R.

    Human Psychopharmacology (Human Psychopharmacology)  36 ( 2 )  2021.03

    ISSN  08856222

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    Objective: This study aims to clarify the relevant factors influencing practitioners' methods of prescribing medications for bipolar disorder, in a nation-wide survey in Japan. Methods: The clinical records of 3130 outpatients with bipolar disorder were consecutively reviewed from 176 psychiatric outpatient clinics. Fifteen parameters, that is, five patients' including five general characteristics (sex, age, education, occupation, and social adjustment), five patients' aspects of mental functioning (onset age, comorbid mental illness, rapid-cycling, psychopathologic severity, and followed-up years), and five practitioners' characteristics (sex, age, specialist experience, clinic standing years, and location), were evaluated. The number of psychotropic drugs (mood stabilizers, antidepressants, antipsychotic drugs, anxiolytics, and hypnotics) was used as an index of pharmacotherapy. Converted data from each practitioner-unit were analyzed. Results: Seven factors (patient's social adjustment, patient's psychopathology, patient's comorbid mental disorders, patient's followed-up years, doctor's age, clinic running years, and patient's education years) were correlated to the number of psychotropic drugs. Multiple regression analysis showed that the severity of illness (poor social adjustment, and comorbid mental illness) and an intractable disease course (long followed-up years), were significantly associated with the number of psychotropic drugs. Conclusion: Our findings indicated that patient-related conditions affected psychotropic polypharmacy more strongly than did practitioner-related conditions.

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Presentations 【 Display / hide

  • 初発分裂病のDUP(未治療期間)と治療コンプライアンスに関する検討

    Kobayashi Hiroyuki, Suzuki Yukiko, Yokoyama Tomoko, Tsukahara Mihoko, Kikuchi Toshiaki, Yamazawa Ryouko, Mizuno Masafumi, Yagi Gouhei, Kashima Haruo



    Oral presentation (general)

  • 非定型抗精神病薬の普及度と適応に関する研究

    Tomita Masayuki, Watanabe Kouichirou, Kikuchi Toshiaki, Takeuchi Hiroyoshi, Kishimoto Taishirou, Nomura Kensuke, Nakagawa Atsuo, Yamazawa Ryouko, Uchida Hiroyuki, Suzuki Takefumi, Nozaki Shouko, Tomita Atsuko, Takano Harumasa, Inagaki Ataru, Yagi Gouhei



    Poster presentation

Research Projects of Competitive Funds, etc. 【 Display / hide

  • An fMRI study to explore neural activity of praecox feeling


    MEXT,JSPS, Grant-in-Aid for Scientific Research, Grant-in-Aid for Early-Career Scientists , Principal investigator


Courses Taught 【 Display / hide











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