查無明確生理病因的功能性身體症狀，在精神科以外的專科，主要根據身體症狀種類命名，例如慢性疲勞症候群、纖維肌痛症、腸躁症等。但在精神科，這些診斷具有相似的心理特徵，當代主流的精神科診斷系統稱之為身體症狀障礙症。對於這類症狀，台灣民眾也會以自律神經失調，腦神經衰弱等詞彙加以稱呼，但這些概念已非當代國際上通用的診斷。在台灣已有一系列對此類議題進行的心理與生理研究，探討的主題包括：(1)精神科如何看待功能性身體症狀；(2)身體型症狀該如何測量，或做標準化的評估；(3)該如何看待身體型症狀與憂鬱、焦慮的重疊；(4)不同的功能性身體症狀，是否伴隨不同的心理特徵；(5)身體型症狀在台灣常被民眾稱為自律神經失調，這些病患是否真具有自律神經活性的特徵；(6)為什麼台灣民眾更能接受自律神經失調的說法；(7)對於此群病患，臨床端該如何看待自律神經活性檢測的結果；(8)對於此群疾患，精神科觀點的機轉為何。本文對這些發現進行簡要的說明，期望對讀者有臨床或研究上的助益。

“Medically unexplained” functional somatic symptoms are usually named according to the somatic presentations beyond psychiatry, such as chronic fatigue syndrome, fibromyalgia, and irritable bowel syndrome. In psychiatric field, these diagnoses have similar psychological features and can be named as somatic symptom disorder in current diagnostic system. In Taiwan, general population also name these symptoms as “autonomic dysregulation” or “neurasthenia”; however, these are not contemporary constructs. There have been series of psychological and physiological studies exploring this topic in Taiwan, including: (1) how to understand functional somatic symptoms from the psychiatric perspective; (2) how to evaluate somatic symptoms with standardized manners; (3) how to understand the overlapping of somatic symptoms, depression, and anxiety; (4) whether the distinct somatic symptoms are associated with different psychological features; (5) whether the patients with somatic symptoms have autonomic features; (6) why people in Taiwan tend to use the term "autonomic dysregulation"; (7) how to interpret the results of autonomic measurements in patients with somatic symptoms; (8) how to understand the mechanisms of functional somatic symptoms from the psychiatric viewpoints. The findings of these studies were introduced in this article.