Although the word sleep is often used in correlation with hypnosis and hypnotherapy, hypnosis is not a state of deep sleep. It does, however, induce a trance-like condition that actually increases the subjects state of awareness in their own subconscious. Because the subconscious is under the mental surface and we are mostly unaware of it in our normal conscious state, the hypnotic state is necessary to gain access to it.
A hypnotherapist, after the subject is in their hypnotic state, is able to suggest ideas to them as a form of therapy. These ideas are implanted deep into the psyche and can help with any number of issues. For example, while under hypnosis, a therapist may be able to suggest to you that cigarettes taste and smell awful, they make you sick and you want nothing to do with them. This is only a suggestion and may not work 100% the first time. Instead, the next time the subject picks up a cigarette, they may smoke it but will gain less enjoyment from it, hopefully leading them to eventually quit.
Hypnosis is the act of hypnotizing a subject. The practice of healing or positive growth through hypnosis is known as hypnotherapy. This is the...