In the late nineteenth century, German-speaking physicians and psychiatrists intensely debated the benefits and risks of treatment by hypnotic suggestion. While practitioners of the method sought to provide convincing evidence for its therapeutic efficacy in many medical conditions, especially nervous disorders, critics pointed to dangerous side effects, including the triggering of hysterical attacks or deterioration of nervous symptoms. Other critics claimed that patients merely simulated hypnotic phenomena in order to appease their therapist. A widespread concern was the potential for abuses of hypnosis, either by giving criminal suggestions or in the form of sexual assaults on hypnotized patients. Official inquiries by the Prussian Minister for Religious, Educational and Medical Affairs in 1902 and 1906 indicated that relatively few doctors practised hypnotherapy, whereas the method was increasingly used by lay healers. Although the Ministry found no evidence for serious harm caused by hypnotic treatments, whether performed by doctors or by lay healers, many German doctors seem to have regarded hypnotic suggestion therapy as a problematic method and abstained from using it.
Maehle, A. (2017). A Dangerous Method? The German Discourse on Hypnotic Suggestion Therapy around 1900. Notes and Records: The Royal Society Journal of the History of Science, 71(2), 197-211. https://doi.org/10.1098/rsnr.2017.0006