Well I'm only 16 and I'm not interested in anything medical at all, but I feel like it could be possible. I don't want to sound racist or anything but if a big part of the black community comes from lower classes they would be less treated/less medicated than higher classes, who tend to be white people and so more immune to the pain because they have learnt to suppress it. Maybe that's what they mean by it? Of course that would include everyone from lower classes and it's about wealth rather than race but I think they are affiliating black people with poverty.
Again, I'm uneducated and just trying to see a side to it, so don't be ruthless with me if I'm wrong ff.