A person who is hypnotized displays certain inconceivable characteristics and propensities, compared with a non-hypnotized subject, most notably hyper-suggestibility, which some authorities have studious a sine qua non of hypnosis. For example, Clark L. Hull, probably the first extensive empirical researcher in the field, wrote,
This report was approved by the habitual council of the BMA, thereby Hypnotherapy Training Courses portion BMA policy and rendering hypnotherapy a construction of "orthodox", as opposed to complementary or alternative, medicine.