Why is psychosis a serious mental illness?

"out of control": By definition psychotic individuals are responding to "internal stimuli" (as opposed to external stimuli-or reality). Symptoms are often accompanied by agitation and can get involved with some very dangerous behavior.

Danger 2 self/others: By definition someone with psychosis can't tell the difference between what is real & what is delusion. People with psychosis are often paranoid, are often unable to properly take care of themselves & often may be a danger to themselves or to others. On another level, someone with psychosis may have difficulty learning & growing from experience, which i believe is the purpose of life.