h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Absoutely, says Mindreader. "The worst thing that can happen is that the client may become too comfortable and fall asleep."
My view, based on what I witnessed many years ago when I were nobbut a lad serving in the RAF, is that it all depends on what you mean by safe.
I shared a billet with about a dozen others, one of whom was a hypnotist, and gave demonstrations to prove it. There were several good subjects in the billet whom he could hypnotise readily, and one who was an exceptional subject, who, after a few sessions, would go into a hypnotic state even when he was not supposed to be taking part in the session. The hypnotist (Pete) was mainly doing the standard sort of things that stage hypnotists do, for the amusement of the others who were watching. On one occasion he tried, all too successfully, to induce a positive hypnotic illusion of a disembodied head on a chair, using the exceptional subject (Dave) for this demonstration, explaining that this needed one of the deepest states of hypnosis to be successful. Dave duly reported, in an agitated state, that he could see the disembodied head. Pete brought him back to a normal state of consciouness with the usual instructions that he would be happy and relaxed. Unfortunately he wasn't, and that evening was physically shaking and in a distressed state of mind. Peter had to hypnotise Dave several times, giving post-hypnotic suggestions each time that he would returned to a relaxed state, before the shaking and agitation subsided after a day or two. Probably Dave suffered no long term effects, but he did experience distress for a couple of days.
On another occasion during my service a stage hypnotist came to perform at the camp cinema on the station where I was serving. I went with a friend, George, who proved to be a good subject and went onto the stage to take part. The hypnotist gave him a post hypnotic suggestion that whenever he flicked his cigarette lighter, George would stand up and shout out loudly, "You're a stupid old fish face".
The hypnotist then roused him and sent him back to his seat (next to me). After a time, the hypnotist flicked his lighter and George stood up and shouted as he had been instructed, and then looked round in a bewildered manner and sat down again. The audience laughed gleefully, but it was obvious to me that George was upset at his behaviour, and was completely unprepared for it. The show went on and a few minutes later the procedure was repeated. George was definitely upset this time, and when it happened for a third time he was going to leave in the middle of the performance. I assured him that it was not his fault, and he reluctantly stayed, but his distress was genuine.
So hypnosis by therapists is no doubt perfectly safe, but abuse of the subjects for the purpose of entertainment can cause distress to them, indicating that the subject is not completely in control of the situation when under hypnosis.

"So hypnosis by therapists is no doubt perfectly safe, but abuse of the subjects for the purpose of entertainment can cause distress to them..."

Thanks, Al. I agree completely, though I should point out two things: firstly, the best modern stage hypnotists are fully trained to deal with negative experiences of the kind that you mention, and secondly they work with much deeper levels of trance than are normally necessary in the therapy room.

There is no way that I, or any therapist that I know, would treat a subject in the way you describe.

Mindreader