What is hypnosis? Hypnosis is a trance state characterized by increased suggestibility, relaxation and heightened imagination. It is a normal state that most people experience on a regular basis, such as when daydreaming or when "losing yourself" in a book or movie. Just as when daydreaming or being absorbed by what you are reading, you are fully conscious, but you tune out most of the stimuli around you. This gives you the ability to focus on the problem at hand, to the near exclusion of any other thought.
How does hypnosis work? Hypnosis works by altering your state of consciousness in such a way that the analytical left-hand side of the brain is turned off, while the non-analytical right-hand side is made more alert. Since the unconscious mind is a deeper-rooted, more instinctive force than the conscious mind, this is the part which has to change for the patient's behavior to alter.
For example, a patient who consciously wants to quit smoking may try everything they consciously can to do it, but will still fail as long as their unconscious mind retains the urge to smoke. Progress can only be made by reprogramming the unconscious so that deeply seated urges are diminished and beliefs that they cannot quit are abolished.
How many sessions will it take to work? The number of sessions required depends on the type of problem, severity, and your motivation to change. Most people see dramatic improvement, if not a complete change, in just one session. Habits such as smoking are usually cured in 1 or 2 sessions, whereas ongoing issues such as learning to eat healthier are most effective if done a few times a year.
Is being hypnotized like being asleep? Although you are in a very relaxed state, hypnosis is not like being asleep since you are aware of everything around you. Hypnosis is much more similar to meditation, where you have a strong internal focus and are very relaxed, yet you are in complete control. Unlike sleeping where you feel as if you are a passive recipient of your dreams, you are actively choosing what to visualize and are hyperattentive to the topic at hand.
Do I need to feel like I have been hypnotized for it to work? Some people come out of a session and do not believe that they had been hypnotized because they do not have a clear conception of how hypnotism is supposed to feel. Since a person is completely aware under hypnosis and they do not experience a loss of control, some people will claim that they did not go "under". Interestingly enough, it is very common for these people to completely change their habits after being hypnotized, claiming that they just "suddenly realized" how important it was for them to change.
Will hypnosis work if you do not believe in it? In my experience, hypnosis is extremely effective even for those who claim not to believe in it. However, as with anything else, telling yourself that you cannot change can be a self-fulfilling prophecy. Medical research has shown time and time again that even widely accepted treatments are less effective for those who do not believe that they will get better.