This paper presents the historical evolution of medical diagnosis related to diseases without lesions. We focus on this problematic field of history of medicine observing the difficulties to get clinical evidences using pattern procedures. We approach the nosological classifications for these diseases during the 19th century based on three paradigms: irritability, arc-reflex, central nervous system. During the 20th century, we focus on the psychogenetic paradigm and on the transformations that those diagnosis have had in the different editions of the Diagnostic and Statistical Manual of Mental Disorders. Finally, we approach some of the new names that diseases without lesions have achieved nowadays, taking functional somatic syndromes as a contemporary example and analyzing the (i)legitimacy dilemma that surround that kind of illnesses.
Symptoms without lesion; psychosomatics; history of medicine