I would agree with anonymous, but I think some aspects of it show much more promise. Hypnosis, which eventually is trained as self-hypnosis, can be a way of putting a person in a more relaxed state that allows them to accept and process information and suggestions. I am largely a cognitive-behavioral psychologist who believes that how a person thinks can determine how they feel. If I can change the way that they think and actually attempt to program positive affirmations, I can change negative thinking into positive thinking and positive behavior. Of course, I can do the same thing through conscious therapy, but sometimes my patient is just to anxious and resistant. I have tried to accumulate every tool and would not discard one that might work for someone.
Hypnosis has shown short-term effects in cessation of smoking, but long-term effects depend on continued practice. Similar results have been found with meditation, but meditation probably takes longer because it is less directive and directed to a single outcome. Meditation can be a mindfulness technique.