If you never heard of it, it's because it's not a real thing.

It's something cops made up for an excuse when they kill someone

Some of those determinations shield the police from potential accountability: notably, “excited delirium,” a so-called syndrome not recognized in the Diagnostic and Statistical Manual of Mental Disorders or the International Classification of Diseases, with research finding that most deaths attributed to the term involve aggressive restraint.

Cops choke someone to death. And then have the balls to blame it on their victims trying not to die for what caused them to die.