People suffering from mental issues like this usually aren't thinking fully rationally. A good friend of mine had a sudden schizophrenic break once. Before it

People suffering from mental issues like this usually aren't thinking fully rationally. A good friend of mine had a sudden schizophrenic break once. Before it happened he was very much a math/science/computer guy, smart and logical and very anti religious. But after something happened that changed his brain chemistry he wasn't able to keep up the same level of logical thinking; he failed out of classes he was previously doing well in, lost his job, lost his girlfriend, and started behaving strangely. He had begun hearing voices and having strange thoughts and couldn't always form coherent sentences or ideas. Since I was a close friend he eventually confided in me some of his personal thoughts, like that he thought the world was ending and he was hearing from angels and demons. He would do irrational things like play the same songs over and over on his speakers for me, as though he was trying to use them to communicate some hidden meaning that I couldn't grasp from listening to them (they were very random songs without any obvious intrinsic meaning). On one occasion he suddenly became violent and lashed out towards some people he had previously gotten along with, and when I looked into his eyes in that moment it was like there was zero recognition despite our years of friendship. It was very sad and a bit frightening to see him go through such a drastic and sudden change in personality and ability.