Hypnotism is reliant upon one thing - belief. Not just belief in hypnotism itself but also in the ability of the hypnotist to actually put you in a trance.
From what I've learnt about it, the trance state is really just a very relaxed state of mind.
You're led into this state by the hypnotist who uses an induction with specific language patterns in order to gently lead you into zone.
While in this relaxed state, your mind becomes very suggestible. What that means is that, as the hypnotist continues to talk to you, he's able to speak to your subconscious mind, again, using crafted language patterns in order to make some sort of change in you on a deeper level.
But, say for example the hypnotist is helping you quit smoking, what I also discovered is that all they are really doing is giving you permission to do something you have within you anyway.
So you could switch off your smoking habit yourself if you knew the technique to change your mind, but your lack of belief that you have much power of your habits and your mind stops you being able to.
Because that part of your brain is now being accessed in exactly the same way you could, but instead by a trained hypnotist, someone you believe has the ability to change your habit, you allow the change to happen.
These moments, the trance state moments, happen to us all the time throughout every day. Most of the time though, we're not even aware that we just kinda drifted away.
You'll notice it when you're having a long conversation with someone and you're explaining a long story about something, most of us have a short attention span. If you pay enough attention to the person you're talking to, at some point you might notice their attention wander off. Even just briefly. And it's in these moments when their focus goes, that you can speak to a different part of their brain, a part that doesn't assess and filter what's going in making it easy to manipulate.
So yes, hypnotism is real, it's based on language and psychology, not some sort of magic, and it's pretty powerful skill when done right.
I learned a lot about the way the mind operates and how easy it is to interrupt the patterns from Derren Brown. The guy is a genius with this stuff, and some of what he does will amaze you. check some of these out:
This one is shows you a language skill called NLP.
https://www.youtube.com/watch?v=sEmCQzueyEQ
And this is another one about language patterns but check out anything he's done on youtube :)
https://www.youtube.com/watch?v=sX-OuAoR3jA