This article focuses on one, but that statistic is buried in the article.

I've never thought too much about it, but paramedics and police officers must really see so much that they want to forget. It's got to be so hard to cope with, even with therapy (which apparently very few are getting). If there is a school shooting, or a workplace incident, or if anyone else views something horrific, it's almost expected that they'll work through it in therapy. Imagine having to see that sort of thing over and over and over...