統合失調症の維持期の治療において, 抗精神病薬が脳内のドパミンD2受容体を持続的に遮断するために, 薬の濃度を出来るだけ一定に保つ処方の設計や薬剤の開発が行われてきた。しかし統合失調症患者の幻聴症状の出現と消褪は1日単位で見た場合, 必ずしも抗精神病薬による脳内のドパミンD2受容体の遮断の程度とは関連はなく, むしろ概日リズムの存在が示唆され, 夜間により多くの幻聴症状を認めた。つまり, 統合失調症の急性期治療の後に精神病症状が残存している場合, 急性期同様のドパミン受容体の持続的な遮断が必要ではなく, 概日リズムに注目した治療が有効である可能性を明らかにした。
In the maintenance treatment of schizophrenia, prescription regimens and new drugs are designed to keep drug concentrations as constant as possible in order for antipsychotics to block the dopamine D2 receptor in the brain. However, our results have revealed that the appearance and disappearance of hallucinations within a day in patients with schizophrenia is not always related to the degree of blockade of dopamine D2 receptors by antipsychotics, but rather the presence of circadian rhythms. Moreover, hallucinations more frequently occurred at night. Thus, if psychotic symptoms remain after the acute phase treatment of schizophrenia, it does not seem necessary to sustain blockade of dopamine receptors as in the acute phase; rather, the treatment focusing on circadian rhythm of symptoms may be effective.
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