Division of Clinical Neuroscience

Research on dopamine supersensitivity psychosis (DSP) and the long-term prognosis of patients with schizophrenia

　Approximately 20% of individuals with schizophrenia experience a good long-term prognosis, and 30%-40% develop treatment-resistant schizophrenia (TRS) at some time point during their clinical courses. The majority experience at least one relapse episode due to a variety of reasons. Accumulating evidence has revealed several factors related to remission or treatment-refractoriness. We strongly believe that dopamine supersensitivity psychosis (DSP, or the dopamine supersensitivity state) could greatly influence the long-term prognosis of schizophrenia patients as well, it is thus important to collect more evidence: DSP can be the trigger of a relapse episode, and a relapse episode can promote the further development of DSP, possibly leading to TRS. By performing detailed analyses of DSP plus other factors that may be predictive of the long-term prognosis, we are aiming to develop a more valuable and practical method for predicting the prognoses of patients with schizophrenia.

Research on clinical psychopharmacology for schizophrenia

　We are studying several clinical questions in the area of pharmacotherapy for schizophrenia for which sufficient evidence has not been obtained. In particular, clozapine, long-term antipsychotic injectable forms, and dopamine partial agonists are featured in our study. Toward the goal of overcoming treatment impasse in clinical practice, we are collecting clinical data that contribute to physicians’ decision-making. Our projects with other psychiatric hospitals/facilities in Chiba prefecture are now underway.

Research on the etiology of treatment-resistant schizophrenia

　Although clozapine is a highly effective for TRS patients, there are still many patients who do not respond sufficiently to this agent. In attempts to develop effective treatment for TRS patients, we propose that it is important to delineate TRS patients from other types of patients with clinical courses that differ from that of TRS. We are studying this topic by applying genomic, chemical, electrophysiological and neuroimaging (MRI) techniques.

Research on tardive dystonia

　Tardive dystonia is one of the most serious adverse events in treatment with antipsychotic medication. There has not been an effective treatment available to all patients with tardive dystonia. We are conducting mainly genomic research regarding this symptom.

　We always welcome collaborative studies on these topics with researchers in and outside of Japan. If you are interested in our research activities, please send an e-mail to Dr. Nobuhisa Kanahara at kanahara@faculty.chiba-u.jp.