The following links provide articles and research material related to the application and effectiveness of hypnosis and hypnotherapy.
EEG technology now allows us to record brainwave activity during hypnosis. You can see here several snapshots of brainwave activity whilst experiencing various hypnotic phenomena.
International Journal of Clinical and Experimental Hypnosis, 67:3, 336-363, DOI: 10.1080/00207144.2019.1613863
Psychosomatic Medicine 2005 May-Jun;67(3):376-83
European Journal of General Practice June 2002, Volume 8