My friend and I were watching a horror movie (the remake of Dawn of the Dead to be exact) and very early into it I noticed he started to shake and then convulse very violently. He fell out of his chair and knocked over some nearby furntiure on his way down. It really reminded me of a seizure. When he came to he said that he had blacked out and was having a difficult time catching his breath. His skin was very pale at that point. He kept asking what happened because he had no recollection of anything. I asked if anything like this had happened before and he stated that he had one similar experience as a freshman in collage and watching a violent horror movie sparked this reaction. If the two occurances are linked to viewing horror movies, what could be the actual cause and what type of medical attention should he seek?