This is something I'd be comfortable defending. Mental problems do not need to be inherent from birth; whereas minority groups are highly correlated with crime

This is something I'd be comfortable defending. Mental problems do not need to be inherent from birth; whereas minority groups are highly correlated with crime and low income as a result of American class divisions, at a glance, I can see several ways to argue that minorities are at least more susceptible to mental illness. This isn't ethnic so much as it is environmental living conditions in poverty. For one, you have malnutrition, which is an entire precursor to mental illness in of itself. Of course you can't reasonably argue that minorities have an inherent predisposition to mental illness (it'd be frankly racist, and without much evidence I believe), but in practice, they probably do have a predisposition to it over the course of their lifetimes from a statistical standpoint.