How well did you know them? The people I know were either always smart but still laid back, and pot only loosened up their laziness a bit more even though they are still smart behind all that laziness, or they were just pretty stupid in the first place and then began smoking pot. Prime example of the latter was the kid who was high and decided to leap over the trash fire in my backyard with gasoline on his legs. Long story short, he ended up in the hospital for about six months and my family got the shit sued out of them. He ran around in circles on fire for like twenty seconds, even though our house use to be right next to a fucking lake.