Truth is, mental illness just a fuzzy gray line.
What society deems to far from the norm is a mental illness. Homosexuality is pretty accepted these days a generation or two ago it was a mental problem. Now transgenderism is going from a mental illness to not.
Back in the day, I'm not sure if hearing God talking to you was normal. I think more than one person said they were the son of God, Jesus just preached something good and people believed him.
Christianity is born from the ideals of equality, redemption, and revenge. It was from the slaves of Egypt who wanted to say that this life sucks but that their masters will go to hell for being bad to them. It is also for an easy path, just to believe and your sins will be forgiven.
I don't know whether I love those Christian ideals of washing away sin and that we are all equal and loved in God's eye, or see them as something weak and a way for the weak to guilt the strong into treating them better and a way for the weak to create an illusion where they are not weak.
I am torn on Christianity.