This study questions the widely held assumption that the phenomenon known as mass psychogenic illness (MPI) exists per se in nature as a psychiatric disorder. Most MPI studies are problematical, being descriptive, retrospective investigations of specific incidents which conform to a set of pre-existing symptom criteria that are used to determine the presence of collective psychosomatic illness. Diagnoses are based upon subjective, ambiguous categories that reflect stereotypes of female normality which assume the presence of a transcultural disease or disorder entity, underemphasizing or ignoring the significance of episodes as culturally conditioned roles of social action. Examples of this bias include the mislabelling of dancing manias, tarantism and demonopathy in Europe since the Middle Ages as culture-specific variants of MPI. While 'victims' are typified as mentally disturbed females possessing abnormal personality characteristics who are exhibiting cathartic reactions to stress, it is argued that episodes may involve normal, rational people who possess unfamiliar conduct codes, world-views and political agendas that differ significantly from those of Western-trained investigators who often judge these illness behaviours independent of their local context and meanings.