One of the most fun experiences I’ve had in teaching writing was when I first taught metaphor to people with chronic mental illness. When teaching I always define metaphor as something is something else. A metaphor: Healing from trauma is eating a raw onion.
For many of my students part of their mental illness is believing something is something else, as in a delusion such as a toaster is really a spy communication device or “I am really the lost princess daughter of a Beatle.”
For some of these students the idea that people without mental illness also indulge in something is something else thinking, in metaphor, is a revelation.