A Florida school district has agreed to pay $600,000 to settle a case involving a principal who hypnotized students, three of whom died shortly after (some from suicide). Many of the reports in the media include statements drawing a causative link between the hypnosis and the suicides.
For example, the lawyer for the families of the students is quoted by the Washington Post as saying:
He altered the underdeveloped brains of teenagers, and they all ended up dead because of it.
The Tampa Bay Times quoted a psychologist, Richard Spana, as saying:
The issue in working with hypnosis is that there can be latent things that are triggered, like past experiences and memories, and the patient can have a bad reaction... Does hypnosis cause suicide in and of itself? That's not really likely. Can it trigger some sort of mental health problem that was dormant? Yes.
These statements were also repeated by the Washington Post.
This book compiles some statements dating back to the 1960s that also suggest a widely-held belief that using hypnosis on depressed patients increases their risk of suicide. The author says that there is a widespread belief among clinicians that hypnosis carries an increased risk of suicide. He dismisses this belief on the basis that some of the mechanisms by which the link is claimed to act are based on faulty assumptions. However, he does not mention any evidence refuting such a link, either.
Meanwhile, a television mentalist, the Amazing Kreskin, is quoted by the NY Daily News as saying that it is impossible for hypnosis to cause suicide:
If it's possible to cause suicide through hypnosis, should I seriously consider going on satellite television with the attempt to attract viewers who are members of ISIS and then bring about mass suicide of our enemy?... The question I suggest is who in the hell had the asinine, imbecilic, stupid, unscientific idea that this had to do with hypnosis?
which states that hypnosis cannot singlehandedly cause suicide, but doesn't address whether it can be a contributing factor in someone with existing mental health issues. Similar statements were made by other personalities.
So to summarize: we have people saying that the claim is feasible, and people saying that the claim is ludicrous. I have not seen any facts or evidence, though.
Is there any evidence one way on the other on whether hypnosis can trigger latent mental health problems or exacerbate existing mental health problems, and thereby be a contributing factor in a suicide?