Can a person's susceptibility to hypnosis be altered? It is commonly quoted in popular literature that 10% of people are &quot;highly hypnotizable&quot;. Given a set of 10 suggestions, such people would have 7 or more suggestions become active. On the other end of the spectrum, there are people who are very hard to hypnotize and will have 0 out of 10 suggestions become active. Everyone else falls somewhere in between.
I'm interested if the person's susceptibility to hypnosis can be altered? Can a person who would previously respond to 7/10 suggestions be made to respond to 1/10, thus becoming hard to hypnotize (or vice versa)?
If so, what is the mechanism behind such change - is it localized to some brain area?
There is no a single answer for this, but I will tell from what I have read of Milton Erickson's ideas.

Everyone is suceptible to hypnosis. The difficult in being hypnoized depends on the person's experience more than a specific part of the brain, and this implies that the most important thing is how the hipnotist is capable of capturing the person's unconscious attention, which is purely determined by the person's experience.

In conclusion, the person's suggestability is completely alterable. In my experience (not too much), if you fail hypnotizing someone and you do not handle ir properly, the next time that person will be less suggestable. This is only an example, there are many other factors that influence this process.