What are some examples of how religion is a mental illness or cause of a mental illness?

There are people who think they must go to a dark building and kiss candelabras in order to make their relatives healthy.

There are people who go to a man, mumbling in an ancient form of their language, wearing a dress and a chimney on his head, waving a purse on fire and listen to him talking about how bad being gender non-comforming…

If that’s not mental illness, I don’t know what it is!