Day persons, night persons, and variability in hypnotic susceptibility

Area of Science:

• Chronobiology
• Sleep Medicine
• Psychology

Background:

• Individual differences in circadian rhythms, specifically 'day' and 'night' persons, influence various physiological and psychological processes.
• Hypnotic susceptibility, a measure of an individual's ability to experience hypnosis, has been explored for temporal variations.

Purpose of the Study:

• To investigate the within-subject variability of hypnotic susceptibility over time in relation to circadian typology.
• To examine potential correlations between hypnotic susceptibility, body temperature, and meal times.

Main Methods:

• Two experiments were conducted using the Harvard Group Scale of Hypnotic Susceptibility, Form A, and the Stanford Hypnotic Susceptibility Scale, Form C.
• Participants, categorized as day or night persons, were assessed for hypnotic susceptibility at various times throughout the day.

Main Results:

• Day persons demonstrated peak hypnotic susceptibility at 10 a.m. and 2 p.m.
• Night persons exhibited peak susceptibility at 1 p.m. and between 6 p.m. and 9 p.m.
• Observed peaks in body temperature were associated with meal intake, not directly with hypnotic susceptibility.

Conclusions:

• Hypnotic susceptibility exhibits temporal variations influenced by an individual's circadian typology.
• The findings suggest the potential role of ultradian rhythms in hypnotic responsiveness, independent of circadian temperature fluctuations or meal times.