For those who are suggestible to hypnosis, a short session prior to sleep may improve both the quality and quantity of deep, slow-wave sleep [SWS], according to a study published in the journal Sleep (2014; 37 , 1143-52). Deep sleep is the most restorative sleep, experts say, and as people age, the amount of deep sleep they get diminishes. Researchers in Switzerland are involved in a project to identify psychological and neurophysiological mechanisms underlying the role of sleep for memory and mental health.
As part of this project, Björn Rasch, PhD, professor in the department of psychology at the University of Fribourg, conducted a study with 70 healthy women aged 18-35 to determine whether a hypnotic suggestion to “sleep deeper” extended their SWS time. Investigators randomly divided the women into two groups: one listened to an auditory tape with hypnotic suggestions; the other listened to a control tape. EEG recordings were used to monitor brain wave activity and sleep patterns. All women were allowed to nap for 90 minutes. Through prestudy testing, some women were identified as being “highly suggestible” to hypnosis, while others were classified as “low suggestible.”
Data analysis showed that “highly suggestible” women who listened to the hypnosis tape experienced 81% more SWS than “highly suggestible” women who listened to the neutral text; and time awake was 67% less in the hypnosis group. “Low suggestible” participants did not benefit as much from listening to the hypnosis tape.
Lead study author Maren J. Cordi, Dipl Psych, said in a University of Zurich news release, “The results may be of major importance for patients with sleep problems and for older adults. In contrast to many sleep-inducing drugs, hypnosis has no adverse side effects.”