I really think you're just trippin yourself out. Sure, everyone's had a panic high at one point or another... it's similar (but different!) to how sometimes a drunk person can get really violent, but usually they're just loud and goofy. Usually people that are high are just spaced out or hungry, sometimes though there's a panic. Just relax and go for a run or something.

The stuff you read about drugs making people crazy is kind of bunk science. It's impossible to say why peoples' underlining mental conditions come up at different times, but those conditions were there all along, not caused by drugs. I've read the research on the 'link' between schizophrenia and cannabis, and even the papers say that cannabis did not cause the mental condition, it's not a provable hypothesis.