Mentally ill people can do it because their brain chemistry is different than a normal person's. Taking chemicals alters your brain chemistry temporarily. I'm glad to see you don't want to use it, but don't make the mistake of thinking mentally ill people are doing something that they've learned rather than what they've been griefed with living with. You can try and learn to do it on your own if you want, but I have to say I have a lot of doubt as far as it even being possible.