Pretty frightening study. It makes sense if you've ever noticed the correlation between being stressed out and getting sick. There is more info about personality types than just Types A-D, however. For those who don't know their personality type, there are a myriad of sites offering personality type assessment & profiles. There is an online game called The Insight Game (insightgame.org), which is a card game to determine personality type. The game was developed by a psychologist and is quick, free and as accurate as any other test available. Stay healthy!