Jan 2019 update: Given the latest articles on this and a more extensive literature search, I am now convinced about the effectiveness of hypnosis after brain injury than I was when writing this initially. Still, much of this is lower-quality research than I’d like. So the below is still accurate.

I have been overwhelmed with requests following our article about the effect of hypnotic suggestion on working memory performance following acquired brain injury. I present frequent questions and very short answers below. My answers to the questions all originate in the same point: there is insufficient evidence right now to establish whether to use or not to use hypnosis for the treatment of cognitive problems following acquired brain injury. I predict that we should be able to give a recommendation (or refusal) regarding hypnosis following acquired brain injury in 2020.

Frequent questions from patients and relatives:

Question: I have a brain injury. Where can I get hypnosis?
Answer: I won’t give any recommendations. I am a researcher and there is not a firm research-based basis for such a recommendation. If you choose to find a hypnotist, make sure to avoid hypnotists who offer regression to past lives, healing of aura, contact with dead relatives, etc. They have demonstrated an inability to learn from science.

Question: Can I be a test subject in an experiment?
Answer: Unfortunately, not by asking me. If we had experiments with open recruitment, we would recruit through other sources to avoid the strong selection bias.

Question: My daughter is diagnosed with ADHD/Schizophrenia/chronic pain/other – can hypnosis help her?
Answer: The results from our experiment should not be uncritically transferred to other conditions. I do not know enough about the effectiveness of hypnosis for the condition you mentioned here.

Frequent questions from rehabilitation professionals and hypnotists:

Question: Can you send me the manuscript?
Answer: No, the manuscripts will be made freely available if (and only if) there is sufficient evidence to decide if it can be recommended as a generalized treatment. We expect to have that evidence in 2020. Here is a list of all public information about the our experiment, which is more than for most scientific articles. This includes some excerpts from the manuscript in the supplementary materials.

Question: Can you help us get started using this intervention for our clients?
Answer: I’m eager to work with you to set up a research project if you are an institution working professionally with brain-injured patients. That means that you can offer the treatment but you will have less control over to whom and how the treatment is administered while the research is ongoing. These projects are needed to accumulate the evidence to decide if hypnosis can be recommended as a treatment for cognitive problems following acquired brain injury.

Background to the answers

Although our study is very convincing in and of itself, it is just one study and one should remember to factor in prior skepticism and that skepticism should be quite high in this case. The results are surprising exactly because they seem unlikely given prior evidence. One also should consider the fact that the results from scientific studies on humans and animals often fail to replicate. I know of several widely used “treatments” in neurorehabilitation that was introduced because of positive early studies but they are still lingering on even though the collective evidence points to small or no effects. If our results should fail to replicate, its better that hypnosis was never brought to use in neurorehabilitation than spending everybody’s precious time on something ineffective.

I am personally optimistic because I have more (less scientific) sources of evidence than what has been published, but I am also a strong believer in science as the right way to make clinical recommendations. With the ongoing and planned studies, I expect that we have sufficient evidence to make a recommendation (whether for or against) in 2020. We keep the final details about the intervention to research projects until then.

I may come across as dismissive. I really am both personally moved by individual stories and intellectually baffled by the scale of the problem on a world scale. I believe that the solution above will, on average, be the best. One potential advantage of it is that it increases the probability that the treatment, if effective, will be implemented in standard treatment instead of on the all-too-grey market of private hypnotists.

See also my post on what our experiment did not show.