Recent work on sleep.

"The implication of these findings is that the sleeping brain can either generate its own perceptions or it can think about them. It cannot do both at the same time. Dreaming is therefore as hallucinatory and thoughtless (or delusional) as so-called mental illness.

In the second study we tested this hypothesis. When psychotic schizophrenic patients were given the thematic apperception test (TAT), in which verbal descriptions of simple but ambiguous pictures are recorded and scored, when they were awake and asked to report their dreams, they had equally high scores on a bizarreness scale (designed to pick up cognitive discontinuity and incongruity) for both. [N]ormal control subjects have the same amount of dream bizarreness as the patients but are much less bizarre in their wake-state projective test responses.

These findings support the hypothesis that REM sleep is a physiological brain state that produces a distinctive and psychosis-like mental content, whereas during normal waking such properties are suppressed. Put another way: when awake, the brain is normally free of the formal aspects of dream activity. Conversely, normal dreaming is justifiably considered to be an entirely normal model of highly abnormal conditions of the human brain and mind. It is now clear that the kind of consciousness that a person experiences is a function of the state of the brain."

So maybe the brains of psychotic people are dreaming, and simply can't wake up.

I performed some minor edits on the quote above. You can see the original here, and check out the TOC for the whole sleep supplement here.

This interested me too: "Major disasters such as Three Mile Island, Exxon Valdez, Bhopal, and Challenger were all officially attributed to sleepiness-related impaired judgment in the workplace."