PROBLEM TO BE SOLVED: To provide a novel therapeutic agent for persistent somatoform pain disorder.SOLUTION: The invention provides a chronic pain therapeutic agent containing as an active ingredient aripiprazole (7-{4-[4-(2,3-dichlorophenyl)-1-piperazinyl] butoxy}-3,4-dihydrocarbostyril or 7-{4-[4-(2,3-dichlorophenyl)-1-piperazinyl] butoxy}-3,4-dihydro-2(1H)-quinolinone) which is an atypical antipsychotic agent useful for the therapy of schizophrenia and an acid addition salt thereof or a solvate thereof. The invention also provides an administration method of a chronic pain therapeutic agent, in which the dosage of aripiprazole to a patient is around 0.05-10 mg/kg body weight/day.COPYRIGHT: (C)2015,JPO&INPIT【課題】新規な持続性身体表現性疼痛障害治療剤の提供。【解決手段】統合失調症の治療に有用な非定型抗精神病薬のアリピプラゾール(7-{4-[4-(2,3-ジクロロフェニル)-1-ピペラジニル]ブトキシ}-3,4-ジヒドロカルボスチリル又は7-{4-[4-(2,3-ジクロロフェニル)-1-ピペラジニル]ブトキシ}-3,4-ジヒドロ-2(1H)-キノリノン)及びその酸付加塩又はその溶媒和物を有効成分として含有する慢性疼痛治療剤。アリピプラゾールの患者への投与量が、1日当り体重1kg当り0.05~10mg程度である慢性疼痛治療剤の投与方法。【選択図】なし