There are a few groups of people who can’t be hypnotized for therapy.
Each group has their own reason.
The first group is very young children under age 6.
The reason for this is young children have small vocabularies and short attention spans.
The second group is people with a low I.Q.
The threshold appears to be people who have an I.Q. below 70 can’t be hypnotized. The reason is attention and the lack of ability to process logic. On the opposite end of the scale people with a high I.Q. are very easily hypnotized.
A difficult group to hypnotize is people suffering from schizophrenia.
They can only be hypnotized if they don’t know it is happening. If they know they will successfully resist.
Resisting hypnosis is not the same as not being able to be hypnotized. Anyone can resist hypnosis.
Not everyone enters hypnosis at the same speed. In fact there are some that will enter hypnosis in a few seconds, while others may require much longer inductions.