I started reading clinical psychology books at age 15, literally a book a month. I majored in psychology in college for 4 years. And I've read hundreds of psychology books since college. Hypnotherapy was just the next step up.
I'm a "direct medical hypnotist" in that I help people with severe issues. For several years I worked with 3 actual medical doctors who incorporated "direct" hypnosis techniques for burn patients, cancer patients, PTSD patients and those in extreme physical or emotional pain.
I also studied "indirect" clinical hypnosis techniques which uses metaphors, confusion and story telling techniques which were created by Milton Erickson.
I continued to expand my knowledge of the power of the mind by spending years studying, practicing and helping others using the following:
√ Cognitive Behavioral Therapy (CBT)
√ Progressive Relaxation Techniques
√ Autogenic Training Techniques
√ Guided Meditation Techniques
√ Visualization Techniques
√ Stress Management Techniques
√ Pain Free Childbirth Techniques
After 16 of my 20 years as a medical hypnotist, I began to offer stage hypnosis in regards to helping Corporations because of my knowledge in Medicine, Stress Management and Focusing to Achieve Goals Techniques.
As for "comedy" stage hypnosis for schools and parties, anyone with half a brain and a very limited knowledge of hypnosis can entertain people. It takes very little knowledge of hypnosis to say "relax this muscle, that muscle, sleep, now dance like a drunken monkey."