A [psychological] disorder triggered by [extreme] [trauma] that the mind of the [sufferer] is unable to [cope] with, causing them to [retreat] into a much reduced [state] of [functioning].

Shell shock marked the first real recognized [psychological disorder] and was first [noted] during [World War I|The Great War] as many [soldier]s were coming to the [war hospital]s with nothing [physically] wrong with them but still completely [unfit for war]. It was at this time that the [doctor]s in these [institution]s began to look to [Freud]'s theories that certain mental [trauma]s could produce effects just as severe as [physical] ones.

Shell shock victims, especially those of war, often exhibit a [twitch] in a part of their [body] that is associated with the [trauma]. For soldiers this means that if they saw someone's leg [blown off] then they would develop a tic in their leg. If it was the face, they would have a facial tic, and so on and so forth.

Shell shock (thing)