Mental illness has a negative impact on a person’s life that prevents them from functioning normally. Simply seeing things doesn’t mean someone has a mental illness, and to be diagnosed, there are multiple criteria that need to be met for a diagnosis. Psychics and mediums can see things, but if it doesn’t negatively impact their ability to function, then it’s probably a different thing entirely.

I don’t want to completely dismiss the possibility, but normally if it is mental illness, there are other symptoms accompanying it. If it makes them happy and enriches their life, then it’s fine and best to leave them alone, but if they see things and they also start having grandiose thoughts, then they need professional help.

For example, I think there’s a clear difference between potentially having psychic abilities and being delusional during a manic episode because it’s never just seeing things. However, if someone happens to be both mentally ill and have abilities, I can see how it’d be confusing, but as someone who is mentally ill, I find the need for some people here to conflate the two to be incredibly harmful.