The scene was so terrifying that she became hysterical and couldn't stop screaming.

hysterical 来自名词 hysteria（歇斯底里症），加上形容词后缀 -ical 构成。hysteria 源自希腊语 hystera（子宫），古代认为这种情绪失控症状与子宫失调有关。hysterical 形容人因极度恐惧或激动而情绪完全失控的状态。