As a person with schizophrenia, (I don't have paranoia) but very mild auditory/visual hallucinations and disorganized/odd thoughts, I can see where they're going. I don't get paranoid, nor do my hallucinations increase in number after a few bowls, but if I tend to smoke more often, say 5-7 days a week, I can definately feel a change in perception (i.e. I'll be walking somewhere, and I'll suddenly become hyper aware of my body, and have a very surreal feeling over me) if I smoke too many days in a row- normally, if I toke 2-3 times per week, these episodes don't occur, pot really helps me slow down and focus.

But think about it- all of this evidence that is coming out now about the still developing health benefits of cannabis; are people really going to become disheartened by a few negative effects, particularly a small-scale study on people who already have distorted reality?