The construction of the clinical category dysmorphophobia (now known as body dysmorphic disorder) resulted from the historical convergence of a neologism (coined by Enrico Morselli), a family of clinical concepts (already available during the late 19th century), and a specifiable behaviour (an ‘attitude’ towards part of the self and/or the body). The stability of such convergence has so far depended upon the epistemological capacity of the concepts involved and the social duration of the said attitude. This paper analyses the historical framework within which such convergence took place, and traces the history of dysmorphophobia in qualitative and quantitative terms. With regard to the latter, it compares cases reported before (139 subjects) and after (39 subjects) the publication of the DSM III criteria map. Patients in the former group were found to constitute a more heterogeneous group, and in the latter to have a better outcome. In the pre‐DSM III group, differences were also found between delusional and non‐delusional patients. The implications of these differences are discussed.