The most commonly accepted definition of hypnosis is: critical faculty bypass. While this state is consistently achieved naturally, it is also easy to achieve artificially.
Everyone is capable of achieving a state of hypnosis. In that way, it is the same as any other skill. It is easier for some people to learn and become proficient at. A skilled hypnotist is able to help clients achieve hypnosis within minutes. Once this is accomplished, behavioral work can begin.
A common misconception is that a hypnotized person 'loses control'. This ignores the fact that the subconscious mind is still active and pre-existing beliefs and behaviors are present. There can be a 'sense' of losing control as the conscious mind becomes less active, but it is only a perception. In practice, the conscious mind has relatively little control to start with.
The Negative MotivatorFinding and working with the negative motivator in a behavior is the first goal. If this is skipped, the initial chance of success is reduced and the chance of long term success is even lower. If only the positive motivator, the most obvious part of a habit, is removed, the mind will look for balance. It will often replace the positive motivator that was removed with an alternate positive motivator.
If you take away cigarettes from a smoker, they will often replace them with food, gum, or candy. And sometimes, if they do not, they experience increased stress. Correctly addressing the negative motivator will often drastically reduces a person's reported stress levels. Sometimes the client finds that this alone will create the desired change. Once the negative motivator is addressed, the job of addressing the positive motivator is much easier.
The Positive MotivatorAddressing the positive motivator is what the client has come in for. It is the hypnotist's job to do this effectively. There are rare instances when replacing a positive motivator is appropriate and can be seen as progress. Moving from regular cola to diet cola can be relative progress. But, should not be seen as the end goal by the hypnotist, unless that is specifically what the client has requested.
There are times when a client has high stress but is not aware of, or is unwilling to discuss their stress (depression, anxiety, worry, etc..) When their positive motivator is removed, it is sometimes possible for them to have more severe stress and anxiety. It is important to discuss this possibility with these clients.