hypnosis and sleep
An enduring misconception about hypnosis is that it's basically sleep. It's easy to see how this has arisen. People who are in a deep hypnotic trance certainly look as if they're asleep, with the same changes in breathing patterns, face color and muscle tone, and a number of hypnotherapists and hypnotists still use the command "sleep" when inducing trance. Indeed, the word hypnosis comes from the Greek "hypnos", meaning sleep. However, hypnosis isn't sleep - although it shares some important characteristics with it.
A major breakthrough in our understanding of the relationship of hypnosis with sleep was made by the psychologists Joe Griffin and Ivan Tyrrell, and their studies of the role and function of dreams. Since all mammals dream, it's likely that dreaming serves a basic evolutionary purpose (rather than a rarefied psychological one - unless you believe that your cat or dog needs psychoanalysis of some sort). Griffin and Tyrrell identified this purpose as expectation fulfillment.
Simply put, dreams act out, in bizarre metaphorical fashion, something that happened during the previous day. More importantly, they act out things which have emotionally aroused us in some way. Emotional arousal is unavoidable - countless things happen to us during the day that activates our emotional instincts, both positively and negatively. Let's say somebody cuts in front of you whilst you're driving, which makes you angry, or your boss says something to you which upsets you.
If we act out or express these emotions in some way, then they're discharged and completed. You might give verbal expression to your opinion of somebody else's driving, but perhaps you don't feel able to express your feelings to your boss. Nevertheless, your emotions have been aroused, and they're still aroused when you go to bed at night. It's almost certain you will have a dream that acts those emotions out, expressing what you felt like doing in a weird metaphorical way - perhaps you'll find yourself shouting at a monster, or the French President, or something else which symbolizes your boss.
The reason for this is to flush out unresolved emotions, so that we wake up refreshed and with our nervous systems intact, free of stress and ready to cope with the demands of another day. If we didn't do this, if we carried our unresolved emotions around with us permanently, we'd soon be in big trouble. Our nervous systems would literally be overloaded.
So what does any of this have to do with hypnosis? The key to this is the Rapid Eye Movement, or REM, state. This seems to act like a computer interface, and serves two purposes. First of all, it's the means whereby nature programs us with our instinctive behaviors in the first place - we all experience a vast amount of REM inside the womb, before we're even born. This ensures that every baby is born with the basic instincts it requires to survive in the outside world - for instance, the instinct to suckle at its mother's breast.
Secondly, REM is the means whereby the original instinctive programming can be kept up to date and in good shape. In evolutionary terms, this is crucial - if your instincts are poorly maintained or obsolete, your long-term prospects aren't very appealing! So we need to the ability to learn from our experience and the ability to remove stress from our instinctive nervous systems - REM performs both of these tasks.
The REM state is most commonly associated with dreaming sleep, which can be thought of as a maintenance task. However, as Griffin and Tyrrell point out, it can be activated at other times too. It's there when we daydream, and it's there when we vividly recall something in memory. It's also there when we experience hypnotic trance of any sort. Indeed, hypnosis is nothing less than the deliberate creation of the REM state in ourselves and others.
This explains why people in deep hypnotic trance look sometimes behave as if they're in dreaming sleep - it's because exactly the same things are happening to them as when they're asleep, even though they're not actually sleeping. For instance, hypnotized subjects often hallucinate things that aren't there, as stage hypnosis vividly demonstrates. This isn't so bizarre when you consider that we all have vivid hallucinations every single time we go to sleep and have a dream.
If hypnosis is another way of creating the REM state, then it follows that it also performs the same updating and maintenance tasks as REM. Simply being in REM/hypnosis is enough to let an overloaded brain catch up on its housekeeping and switch off unresolved emotional arousals. This is why people often say they feel better and are able to think more clearly after a hypnotic induction. By deliberately activating the REM state, hypnosis also opens up the interface with the unconscious. This allows new patterns of behavior to be laid down where they'll do the best, right at the unconscious level of instinctive behavior.
All of this is so much more important than simply being an interesting theory. The relationship of hypnosis to sleep explains how hypnosis works and why it is so effective in treating such a wide variety of conditions.