crisis (n.)

early 15c., crise, crisis, "decisive point in the progress of a disease," also "vitally important or decisive state of things, point at which change must come, for better or worse," from Latinized form of Greek krisis "turning point in a disease, that change which indicates recovery or death" (used as such by Hippocrates and Galen), literally "judgment, result of a trial, selection," from krinein "to separate, decide, judge," from PIE root *krei- "to sieve," thus "discriminate, distinguish."

Transferred non-medical sense is 1620s in English. A German term for "mid-life crisis" is Torschlusspanik, literally "shut-door-panic," fear of being on the wrong side of a closing gate.