淡漠症候群被定義為一種缺乏動機之狀態，且此狀態並非源自意識改變、認知功能缺損，或情感上的痛苦。雖然診斷此症候群仍有爭議，但此症候群已被越來越多神經、精神學家注意。本文報告一腦部腫瘤引起淡漠症候群之案例，起初此個案被診斷為憂鬱症，並接受抗憂鬱劑治療。由於症狀持續惡化，經腦部斷層掃瞄檢查，發現松果體區與蝶鞍上區各有一腫瘤。個案接受化學治療、放射治療，以及立體定位電子刀手術後，腫瘤完全消失，個案之精神症狀也顯著改善。本文藉此案例討論淡漠症候群的定義、評估與治療，並提醒臨床基層醫師，面對疑似憂鬱症的淡漠病患，若其憂鬱症狀非典型且抗憂鬱藥物療效不佳，需仔細評估是否罹患器質性精神病，探究其真正病因，始能有效地治療。 （台灣家醫誌2009; 19: 62-70） Apathy syndrome is defined as a state of motivational loss, but this loss is not due to diminished level of consciousness, intellectual impairment, or emotional distress. Although the diagnosis of this syndrome is still controversial, neurologists and psychiatrists have begun to pay it more attention. In this report, a patient had developed apathy syndrome cased by brain tumors. At first, he was diagnosed with depression and received antidepressant treatment. Because of the continued deterioration of symptoms, brain CT scans were performed and one tumor each was found in the pineal and suprasellar regions. This patient underwent chemotherapy, radiotherapy, and stereotactic electronic knife surgery. After therapy, the tumors were completely ablated, and psychiatric symptoms also significantly improved. Herein, this case was used as an example to discuss the definition, estimation, and treatment of apathy syndrome. Clinical physicians need to carefully consider the possibility of organic psychosis if a patient with apathy syndromes yet is diagnosed as depression whose depressive symptoms are atypical or poor responses to antidepressants have been found. Effective treatment can only be achieved with precise diagnosis and proper management. (Taiwan J Fam Med 2009; 19: 62-70)