a former category of mental disorder, including such symptoms as irritability, fatigue, weakness, anxiety, and localized pains without apparent physical causes, thought to result from weakness or exhaustion of the nervous system
See neurasthenia in American Heritage Dictionary 4
noun
A psychological disorder characterized by chronic fatigue and weakness, loss of memory, and generalized aches and pains, formerly thought to result from exhaustion of the nervous system. No longer in scientific use.