In a word, no.
%99 of my friends and associates for the last two decades played roll playing games, most of them adamantly. I am talking hundreds of people that I have known. They are all very sane and it has not affected them in any noticable adverse ways. Role playing games have been blamed since the 70's when the church targeted them purely because of the mystical and demonic subjects. Since then, people cannot get it out of their heads to always question them. I am a church goer, but sometimes the emotional bandwagons that churches get on about things are as bad a gun control advocates: they are completely irrational, unsubstantiated witch-hunts about things that they don't take time to invetigate thoroughly.
Anyway, RPG's are the least of our concerns as far as things that influence people to do crazy things. Having experienced both. I would see a detailed, violent video game to have more of an affect on the psyche than a role playing game, which is nothing more than "reading a book" where you are the character, and write the book as you go. RPG's are very simlar to readin a fiction book, and not many people put action novels on the top of their list of bad things.
JMHO,
thaddeus
Ps- I still play RPG's. It is quite fun to go to the store, buy a bunch of junk food and stay up all night with my friends playing a game. It gives me quite an escape from my grueling studies.