Guess we're just in the 'minority of cases'?

Eh... Yes, as a matter of fact you guys are? Don't know why I need to debate the principle of anecdotal evidences in this discussion 🤔

You could also talk to experts to determine if there's increased risks or not in your specific case. My mother has 6 siblings, one of them had one kid who's schizophrenic, that's one out of 15 kids between my mother and her siblings, nothing hereditary about it (not on our side anyway), shit just happens sometimes.