Meares coined his term from the English atavism, which is derived from the Latin atavus, meaning a great-grandfather's grandfather and, thus, more generally, an ancestor.
As used by Meares, for example, his 1960 work A System of Medical Hypnosis, the term "atavistic regression" is used to denote the tendency to revert to ancestral type: Meares held the view that when in hypnosis, the higher (more evolved) functions of the subject's brain were switched off, and the subject reverted to a far more archaic and far less advanced (in evolutionary terms) mental state; something which significantly altered the subjects' cognitive processing so that they readily accepted internally consistent, literal logic without any of the normal filters and verifications against the objective facts of the real world.
While hypnotherapy that induces atavistic regression for smoking cessation is an area of interest, it is important to note that its effectiveness and mechanisms require further empirical validation.
It should be emphasized that hypnotherapy, when considered for smoking cessation, is recommended as part of a broader program encompassing behavioral therapy, support groups, and other interventions.
The importance of seeking hypnotherapy services from certified and experienced professionals is crucial to ensure both safety and efficacy of the treatment.