I would be curious to know why the mind would use Schizophrenia as a healing mechanism in some that are only lightly emotional disturbed yet can almost entirely neglect those that are severely traumatized.

My guess (only that) would be that "they" are not so lightly disturbed, only one doesn't know about it.

I also would guess that different traumas produce different results. And the trauma depends not only on something external that happens, but also upon the personality that experiences it.