There are different susceptibilities by race after all. Just consider sickle cell anemia.
Then there are cultural norms. If cultural norms tend toward behavior consistent with a schitzophrenal diagnoses, the doctors are not racist to make that diagnosis more often with that race.
Forgive me, but this makes no sense whatsoever:
"Although schizophrenia has been shown to affect all ethnic groups at the same rate, the scientist found that blacks in the United States were more than four times as likely to be diagnosed with the disorder as whites."
Been shown HOW?
By WHOM?
The only way to "show" this sort of thing is by cases.
If there are four times as many cases per capita of blacks having schizophrenia than whites, than this shows that blacks are four times as likely to have schizophrenia.
We don't have access to a "Real Truth Bong Tree" that we can consult that tells us how things REALLY are, so that we can compare the results we have in medical records with
"the real truth". Absent some sort of divine revelation, with the Archangel Raphael standing there and saying "Well, actually, God afflicts all races equally per capita with schizophrenia", we can't bloody well "show" schizophrenia to "affect all races equally" can we?
All we can use are what the medical records show.
There isn't any other source that shows us anything.
"Although schizophrenia has been shown to affect all ethnic groups at the same rate, the scientist found that blacks in the United States were more than four times as likely to be diagnosed with the disorder as whites. Hispanics were more than three times as likely to be diagnosed as whites."
Well, this goes a long way towards explaining all the crazy white people running around out there.