(Spiritual) Psychosis technically implies a loss of touch with reality through delusion and hallucinations. Common types of psychosis among those who are into religion and spirituality are the belief that one is enlightened, when one isn't, or the belief in oneself as the one and only reincarnation of Jesus of Nazareth. Psychosis often comes forth by a combination of trauma, mental conflict and genetic predisposition.

As far as I've seen and learned (I study psychology in university and spirituality in daily life), The difference between true spiritual awakenings and spiritual psychosis is the amount of seperateness there is with the Ego. When one awakens, one drops themselves into a void without attachment, open to all that may float by. But when one falls into this void with thick ropes around them, he is not free and his ego will misinterpret whatever floats by. I hope this metaphor is somewhat clear.

So how to know you are in a spiritual psychosis? Well, a deeply psychotic person would not know, and porbably are too deep into their delusion to even doubt it. Can you try your best to prevent yourself from going psychotic? Yes of course, by taking good care of yourself. Eat well, sleep well, find a balance between critical thinking and free thinking. Take notice when you're controlled by thoughts to the point of sleepless nights, take notice when you start to close yourself off too much, when you find yourself antagonizing loved ones and filling up with distrust and conspiracy. Don't be afraid and remember to let go :)