They then proceed to do incredible things (believing to be vampires, forgetting the number 7, ...).
This looks very much fake to me, as if they were acting.
On the other hand, most comments I got from a few Google searches do not debunk this show, which is quite surprising when looking at the enormity of what these stars are doing.
Were such actions actually scientifically measured/checked, under some reasonable conditions? (the definition of hypnosis is not that important, it can be any stated induced by someone in a typical TV environment - so no day-long dances which bring in some kind of trance, or drugs, or starvation, ...)
Note: a similar question mentioned participants being or not staged - in my case the ones under hypnosis are well-know celebrities, some of them actors, some not. They all claim being genuinely hypnotized.