My 56 yr. old brother was diagnosed with schizophrenia at age 36. He had a normal life up until that time: high-paying professional career, owned his own home, never smoked or drank alcohol, had friends, played sports & was more social than I was. Without having all the variables listed here, I'm wondering if this "later" onset has a genetic component as well. The one variable I can confirm is that he did take (long-term=years of) antihistamines due to allergies & there were two possible (but not medically diagnosed) cases of paranoia/psychotic behavior in two female biological relatives: one maternal aunt & one maternal grandmother. I don't see much info for families on research for "later" or even "late" onset of paranoid schizophrenia.