I started out studying "direct medical hypnosis" for 3 years from actual medical doctors who incorporated hypnosis for burn patients, cancer patients and those in extreme physical or emotional pain. Direct hypnosis was used by doctors to alleviate pain in war time during amputations before the invention of morphine. Under hypnosis, patients felt less pain, had fewer infections and recovered more quickly.
Once mastered, I then studied "indirect hypnosis" techniques at a 1 year school, which emphasized confusion and story telling techniques which were created by Milton Erickson somewhere around 1940.....(boring).
I also studied Neuro Linguistic Programming (NLP) and Conversational Hypnosis techniques which took forever to get comfortable with because they are the opposite of my very successful "direct hypnosis" techniques.
And I've mastered and helped many with Cognitive Behavioral Therapy (CBT) since college (1975). CBT is what psychiatrists and psychologists use and all it means is that they help you bring your issues to the surface so that you can deal with them on a conscious level. An example is: :when did you first feel that way,' 'how did you deal with it back then,' 'how would you deal with it differently today?"
There are also street (impromptu) and stage hypnotists from whom I learned what I needed to know which was on top of medical hypnosis.
On a side note, I was raised around a psychiatrist and a psychologist and I've been reading their clinical psychology books since I was 10, and took 4 years of psychology in college (1971 to 1975) and have read probably hundreds of clinical psych books since (average 1 to 2 books per month for many years). Hypnosis was just the next step to helping others.