A heteroaromatic methyl cyclic amine derivative represented by formula (IA) or a pharmaceutically acceptable salt thereof is useful for treatment or prophylaxis of diseases such as sleep disorder, depression, anxiety disorder, panic disorder, schizophrenia, drug dependence, Alzheimers disease, Parkinsons disease, Huntingtons disease, eating disorder, cephalalgia, hemicrania, pain, digestive diseases, epilepsy, inflammation, immune-related diseases, endocrine-related diseases and hypertension, on the basis of an orexin (OX) receptor antagonist activity.本發明係關於以式(IA)表示之雜芳香環甲基環狀胺衍生物或其醫藥上可容許之鹽,其係基於食慾激素(orexin)(OX)受體拮抗作用,而可用於治療或預防睡眠障礙、憂鬱症、焦慮症(anxiety disorder)、恐慌症(panic disorder)、精神分裂症(Schizophrenia)、藥物上癮症、阿茲海默氏症、帕金森氏病、亨丁頓氏舞蹈症、飲食障礙、頭痛、偏頭痛、疼痛、消化器官疾病、癲癇、炎症、免疫相關疾病、內分泌相關疾病、高血壓等疾病。
