A systematic literature review published in 2018 in the Journal of Clinical Sleep Medicine evaluated the available evidence for hypnosis for sleep improvement …
The team found that, overall, more than a half (58.3%) of the included studies reported hypnosis benefit on sleep outcomes, just over 12% reported mixed results, and less than a third (29.2%) reported no hypnosis benefit. The authors concluded that hypnosis for sleep problems is a promising treatment.
They also highlighted that the available evidence suggests low incidence of adverse events.
Chamine, I., Atchley, R., Oken, B. S. (2018). Hypnosis Intervention Effects on Sleep Outcomes: A Systematic Review. Journal of Clinical Sleep Medicine : JCSM : Official publication of the American Academy of Sleep Medicine, 14(2), 271–283. DOI: 10.5664/jcsm.6952