Speculative links between schizophrenia and urbanization have been based on some sort of big city cold shoulder versus the warm pastoral P's and Q's you get in a small town. Could the simpler explanation just be "the air is dirty?"
Heck one of my neibours has a nickname same as my surname and his other half would nag by calling his name loud at night - that really wasn't helpful for my REM phase sleeps I tell you and one mystery I'm glad that I solved.
Schizophrenia is far more severe than "faint voices in the night". One of the requirements is that the symptoms cause significant impairment to normal function.
Additionally, general physicians are not qualified to diagnose or treat schizophrenia.
Mental illnesses aren't causal labels to be thrown around.