I think it makes more sense to say that LSD and other chemical/man-made drugs have a better chance of TRIGGERING (not causing) a mental illness such a schizophrenia vs. marijuana, shrooms and other au natural drugs.

I don't think pot has an effect like that on the brain.

Nothing can cause schizophrenia, it's something that's always in your head, you can have something trigger it (i.e something tramuatizing) but thats it