No it's the evil influences people allowed in their lives and communities that lead to mental disabilities and sickness. If people stayed true to the exact word of God, satan would have no influence or power and these things would not happen in society. Children and innocent, no matter what adults around them caused to happen, will still be protected by God no matter what.  One of my last questions to God was how does he protect children and faithful who are killed by evil, i found out that.. at that moment its happening he protects their mind so they don't feel anything and the moment of death is painless for them. They move on to eternal love, their killer is damned to eternal torture.