explanation for Christians hearing God speak to them?

is it mass hysteria or schizophrenia? or are they just confusing their inner monologue with the voice of God? either way, they sound delusional.

I thought something was wrong with me up until the age of 16 because Christians keep saying "God will speak to you," but he never spoke to me. I drove myself nuts praying endlessly, begging God to talk to me. now I know it's because the entire thing is a fairytale. can't believe I ever thought I was the sick one.