Hypnotic Susceptibility - Hypnotic Depth Scales

Hypnotic Depth Scales

Hypnotic susceptibility scales, which mainly developed in experimental settings, were preceded by more primitive scales, developed within clinical practice, which were intended to infer the "depth" or "level" of "hypnotic trance" on the basis of various subjective, behavioural or physiological changes.

The Scottish surgeon James Braid (who introduced the term "hypnotism"), attempted to distinguish, in various ways, between different levels of the hypnotic state. Subsequently, the French neurologist Jean-Martin Charcot also made a similar distinction between what he termed the lethargic, somnambulistic, and cataleptic levels of the hypnotic state.

However, Ambroise-Auguste Liébeault and Hippolyte Bernheim introduced more complex hypnotic "depth" scales, based on a combination of behavioural, physiological and subjective responses, some of which were due to direct suggestion and some of which were not. In the first few decades of the 20th century, these early clinical "depth" scales were superseded by more sophisticated "hypnotic susceptibility" scales based on experimental research. The most influential were the Davis-Husband and Friedlander-Sarbin scales developed in the 1930s.