Even when I was in high school (long, long ago, way back in the 1960s), we used to joke about how pot-smokers would suddenly become paranoid. And they really did; it was very scary.
I have two pot smoking nephews. One believes the contrails are evil government experiments on people that make him feel sick from the chemicals. The other one has total Bush derangement syndrome and his own brand of physics.
After the Tucson thing I feel totally creeped out about them.
(I am glad they live far away in Portland Oregon.)