Hypnosis is tricky because just like a lot of psychological treatments, it can be proven successful or a failure. It has worked and it has failed. Overall, it's a tricky risk.
Yes. Hypnosis and self hypnosis have been demonstrated to be useful. Not many rigorous medical studies have been done but there is enough evidence out there to suggest many can benefit. Hypnosis is also good for addressing many conditions that affect blood pressure. for example reducing stress/relaxation, losing weight, stopping smoking and reducing alcohol addiction. I have added a link to a site on self hypnosis which can give you more information.
How well hypnosis works to help people depends on who you ask. Study results have been mixed. A handful of studies found that almost half of patients had stopped smoking by 11 months.
Some experts in hypnosis can use the techniques of hypnosis to hypnotize someone instantly through conversation. This is called covert hypnosis. For more information on covert hypnosis and other forms of hypnosis visit hypnotizepro.com
There is no TM for Hypnosis in any of the versions of the game. Unfortunately, the only way to learn hypnosis is through breeding or your Pokemon leveling up. Level up haunter and it might get hypnosis.
You can get hypnosis training at local shops, or by a trained professional. Hypnosis training can be attained by going to many institutions in California, home of hypnosis training.
Trance is a state of hypnosis.
Hypnosis is not a TM.
There is no hypnosis TM
hoothoot knows how to use hypnosis
A hypnosis practitioner also known as a hypnotist is a person who performs hypnosis on someone else.
Unfortunately, Hypnosis is not a TM in Pokemon Black or White. You would have to get it by leveling up.