Brain Oscillations and Diurnal Variations in Hypnotic Responsiveness--A Commentary on "Diurnal Variations in Hypnotic Responsiveness: Is There an Optimal Time to be Hypnotized?".

A recent study published in the International Journal of Clinical and Experimental Hypnosis reported an interesting diurnal pattern of hypnotic responsivity; specifically, the authors found higher hypnotic responsiveness in a large sample of undergraduates in the morning and early evening. However, they did not have an explanation for this pattern of findings. This pattern is consistent, however, with the theta hypothesis of hypnotic responsivity. Further examination of the associations between brain oscillations and response to hypnosis is needed to determine if specific oscillations such as theta (a) actually facilitate response to some hypnotic suggestions, (b) merely reflect hypnotic responding, or (c) reflect another factor that itself plays a causal role in response to hypnosis.