[Short-lived disorders].

Over the years, most of the mental disorders that are dealt with in everyday clinical practice have changed not only their names but also their conceptualisation. Furthermore, as some disorders disappear or are forgotten, others come into being. Seen from a historical perspective and unlike many of the diseases included within classical medicine, it can be stated that one of the basic characteristics of mental disorders is their short-lived presence in the scientific literature. In this study we analyse the causes underlying the transitory nature of mental disorders. The disappearance of a disorder or the modification of how it is conceptualised may be linked to several different motives. Sometimes they may be due to an evolution of the construct, as a result of new findings. On other occasions the disorder falls into disuse owing to the weakness of the theoretical construct or the clinical research upholding it. Lastly, because the Diagnostic and Statistical Manual of Mental Disorders and the International Classification of Diseases require updates that incorporate new contributions and correct faults in the current model, they give rise to new denominations and definitions in mental disorders. This article analyses these three situations and offers an illustrative example in each case.