Studies have shown that hypnosis have a much greater rate of success when applied to people who believe in the effects of hypnosis as a method to put a person's consciousness into a higher state of suggestibility. Psychologists have not been able to pinpoint the cause of hypnosis but from the evidence gathered from practice, it could very well be the patients under hypnosis playing the role of a hypnotized person as they would believe a hypnotized person should act. Those who strongly disagree with the belief that hypnosis will bring them to a conscious state of higher suggestibility will not be very likely to undergo the effects of hypnosis. Psychologists read a series of simple hypnotic suggestions to test the suggestibility of their patients, called hypnotic susceptbility scales, before providing the post-hypnotic suggestion. Providing that hypnosis works on the person receiving the therapy, it certainly is fast, easy, and effective. So if you believe hypnosis will work for you, go ahead and give it a try with a professional psychologist/psychiatrist.
This is not fully related to the topic at hand but I feel it should be written as a warning: using hypnosis as a means to recover lost memory is rather unreliable and depending on the purpose of the therapy (for example, to be used for testimony in the court of law) can be rather dangerous especially if the hypnotists provides leading suggestions (e.g. you will now remember how your father killed your best friend) which will then lead the patient under hypnosis to come up with memories of the suggested event even if the event never really happened.