I heard of a child that died once from watching a horror movie. I'll see if I can confirm it.

I still can't swim in a dark pool at night, thanks to Jaws.

I think the film "The Exorcist" scared the pants off a lot of people. Some films are very disturbing to young and old. Some years ago Roxanne went to see the movie The Exorcist, which spawned a host of imitations. She says: “The movie had a terrifying effect on me. I had to leave before it was over because I was afraid I would be sick to my stomach and felt like fainting. For about two months after seeing the movie, I continued to be terrified and would have nightmares. I wouldn’t go anywhere alone, would watch over my shoulder all the time and was even afraid to wash my hair for fear something would be hovering over me.” Another woman, who saw the same movie on television, later cut out her four-year-old daughter’s heart because she believed the girl was demonized. TV Triggers Terror When the motion picture about demon possession “Exorcist II” was shown recently on U.S. television, a mother and her four-year-old daughter in Wichita Falls, Texas, reportedly watched it together. One scene is said to depict the cutting out of a girl’s heart to get rid of a demon. The little Texas girl was later found murdered in the same fashion. Her mother was charged with the homicide.

Depends on the age of a child and what there understanding is. You have to apply common sense here. Children who are very young watching a shoot-out or similar were asked what they thought was happening and most replied that the people on the TV were upset because somebody had taken their toys. That was as deep as it went, it meant nothing.