This is the technique employed by stage hypnotists, and in that context, a skilled hypnotist can produce some interesting effects with people. However, the stage hypnotist carefully picks his subjects. These are people that are likely to respond to suggestion especially in that setting. That does not mean that they will respond to suggestion in an actual clinical situation. I have had that experience with more than one patient
The stage hypnotist plays on peoples’ willingness to be exhibitionistic where not much is at stake.
In a clinical treatment situation, patients are often ambivalent about change. They say they want certain changes but they resist them. An ethical therapist using hypnosis as a tool does not attempt to use such a procedure because we realize that we can’t and won’t attempt to “force” someone to do something.
When I received the proper training in hypnosis I began to understand hypnosis as a natural state that people go in and out of, akin to imaginative states we have all experienced. Children are in a trance most of the time and therefore relatively easy to work with hypnotically if one has good rapport with them. Our imaginative states can be positive or negative. Unfortunately many people, and almost all of my patients are besieged with these negative trance states and don’t realize it. Dealing with them and fostering positive trance states is an art and a large part of what I do that I find beneficial for my patients.
Integral to my use of hypnosis are cognitive behavioral techniques which you can read about here.