Conversion reactions such as hypoesthesia or anesthesia, which have appeared in contemporary society, are examined in a survey of the literature. The dynamics from neurophysiologic, behavioristic, and psychoanalytic points of view are considered. The relationship of conversion reactions to hysterical neuroses and the hysterical personality types and the boundaries for inclusion of symptoms are established. Neurologic formulations explore the role of inhibition at an operational level and the correlation between organic brain disease and conversion reaction disorders. Behavioristic and social learning theories deal with the effect of environmental stimulation on conversion reaction symptoms, whereas psychoanalytically oriented theory deals with repression, intrapsychic conflict, condensation, and displacement in producing conversion reaction. The role of culture, not only in expression but in diagnosis, is important to an understanding of the various manifestations of conversion reaction. The variety of subgroup cultural patterns in contemporary American society increases the variety of expressions of intrapsychic conflict or need. Psychological testing decreases the dependence on symptomatic diagnoses, providing information about the cognitive and affective styles that underlie symptoms, be they physical 6r behavioral.In the first 3 months of my work as a emotional and physical symptoms as well: clinical psychologist at the Santa Fe Indian depression, emotional lability, headache, burn-Hospital, four patients who manifested hand ing sensation in neck and arms, a lump in the numbness were referred to me. A casual throat, and back pain. All of the patients were expression of interest in this symptom to the diagnosed as suffering from conversion reaction, medical staff resulted in the referral of six I had understood that conversion reaction, more cases. In none of these cases was there a phenomenon traditionally included as one any physiological explanation for the anes-of two subheadings under hysteria (the other thesia, nor did the symptom follow any of the being dissociation), was not a common disorder currently recognized rules of neurological in routine psychiatric work. In fact, I tended functioning. In each case there were other to view it as a psychological mechanism of Biblical times and of the Victorian era, time " i '. ~~~, T~T and culture bound, no longer relevant in our Requests for reprints should be sent to Molly .