“Last night, you became flagrantly psychotic. It will happen again tonight. Before you reject this diagnosis, allow me to offer five justifying reasons. First, when you were dreaming last night, you started to see things that were not there—you were hallucinating. Second, you believed things that could not possibly be true—you were delusional. Third, you became confused about time, place, and person—you were disoriented. Fourth, you had extreme swings in your emotions. Fifth, you woke up this morning and forgot most, if not all, of this bizarre dream experience—you were suffering from amnesia. If you were to experience any of these symptoms while awake, you’d be seeking immediate psychological treatment. Yet for reasons that are only now becoming clear, the brain state called REM sleep and the mental experience that goes along with it, dreaming, are normal biological and psychological processes, and truly essential ones.”
“Why We Sleep: Unlocking the Power of Sleep and Dreams” by Matthew Walker