In bygone days, the term "neurasthenia," meaning "weak nervous system," was used to describe various forms of insomnia and bodily discomfort whose causes couldn't be determined. Later it was found that the problem lay with the autonomic nervous system, and that it was not weakness, but overexcitement. Thus the name was changed to "dysautonomia."
過去人們以「腦神經衰弱」來解釋種種檢查不出根源的失眠、身體不適，後來發現毛病不在腦神經，而是自律神經；神經的問題也不是「衰弱」，而是過度興奮，因而改以「自律神經失調」名之。