Ronald Vetter is looking for psychological causes for later occurrance of PD. I can think of nothing like that in my past that would account for it. I think about WHY just the same. I remember when, as a pre-teen boy, I spent countless hours ( days ) during the long winter playing with a buddy with toys and rich imaginations, in a not very large room, with an unvented kerosene heater. They were supposedly safe, their pure blue flame guaranteeing complete combustion without carbon- monoxide formation, but I wonder. . . .I still remember the characteristic smell. There is the possibility that very small amounts of carbon-monoxide were formed and that the long-exposure, slight CO poisoning might have been a cause. Does that strike a chord with anybody? Will A. Kuipers ( Dallas, Texas ) ( 75 / dx '91 ) INTERNET:[log in to unmask]