This blew my mind when I first heard of it.
"Parental Germline THC Exposure Leads to Increased Heroin Self-Administration Behavior in Adult Male F1 Offspring"
Basically, the implication of a study carried out on rats is:
you expose someone to THC and *THEIR OFFSPRING* will have increased susceptibility to opioid addiction.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3988557/
And yes, marijuana use can lead to schizophrenia. Especially use of highly concentrated forms of marijuana. Oof.