'Dementia praecocissima': the Sante De Sanctis model of mental disorder in child psychiatry in the 20th century.

The aim of this article is to describe the nosographical contribution of the Italian psychiatrist Sante De Sanctis (1862-1935) to early twentieth-century child psychiatry. De Sanctis first proposed the category of 'dementia praecocissima' in 1906, and it was recognized by Kraepelin. Dementia praecocissima has its roots in a theoretical and methodological conception of mental disorder based on 'psycho-physical proportionalism' and the 'law of circle'. This article deals with De Sanctis's model, which has so far been neglected by historiographers; it shows the pioneering role that this Italian psychiatrist played in child psychiatry in Italy.