The analogy I think of for all of the environmental factors that contribute to sz is tinder. If there is no spark or flame of genetic predisposition to the illness, the tinder (in this case marijuana) will not catch fire to full blown illness. If the flame of genetic predisposition is present, marijuana and other environmental factors are fuel for the fire of full blown illness.
They have found that 79% of the illness is genetic, so any chance to avoid it is good to know.
Jeb didn’t smoke pot until college, I think in his case, he used pot to treat the symptoms of schizophrenia.
A 10 year delay is huge in the lives of young people. Jeb was able to have so many life experiences and learned so many life skills before his scz was full blown.
At Family to Family they taught us (and maybe someone else has more information on this) that the sufferers of scz stop maturing. This seems to be true for Jeb. Those extra 10 years are valuable. We believe this is why Jeb can do the things he can, they are things he learned to do before he was totally disabled by his scz.