During the hypnotic trance one is not fully "asleep". The subconscious mind can also listen in. But it is still a very special state of mind. Something between awake and sleeping. In this balance it is possible to connect both the conscious and the unconscious mind. This makes big change possible because we have conscious influence over unconscious processes.
Problem and Resource
The subconscious never has bad intentions. With some issues this is not obvious, but most problems have a use. If we find out what the idea is behind the problem we can replace it with something more suitable. This makes the energy that was used to prop up the problem free to be used for a solution. After we free up the inner resources we guide them towards a solution.
Some of the phenomena one sees used in stage hypnosis can also be used for therapeutic goals. Our subconscious can for instance give us a sign with the twitching of a finger after we ask a question. Or a trance can be strenghened with a stiff arm. Most of my clients are amazed when they experience those phenomena for the first time.
The subconscious controls almost everything that is going on in our body. This includes bodily funcions like the immune system or blood pressure. That is why medical hypnosis can also help with physical illnesses. It is best use case are chronic illnesses.
Being balanced promotes health. The influence the psyche has on the immune system ist known even in classical medicine. That is why we can say that hypnosis and self hypnosis helps is good for our health. And not just when we have a problem but also as prevention.
Effects of hypnosis
Hypnosis works over time on the inside. The maximum effect of hypnosis is generally not reached during the session but it builds up. The subconscious needs time to process, time to physically make new brain connections.
For this reason it is more advisable to have more shorter sessions instead of a single long one.
I've seen the best success with two to three weeks inbetween sessions.