He began working in 1891 at the Roman laboratory of pathological anatomy of Santa Maria della Pietà psychiatric hospital, directed by Giovanni Mingazzini.

[4] The commitment to children with disabilities remained constant throughout his life, to which he dedicated monographic studies such as "Educazione dei deficienti", published in 1915.

[5] On 6 August 1889, only ten years after the establishment of the first laboratory of experimental psychology at the University of Leipzig by Wilhelm Wundt, and in the same year in which the centenary of the French Revolution was celebrated, the 1st International Congress of Physiological Psychology was held in Paris, chaired by the famous neurologist Jean-Martin Charcot.

[9] The main purpose of the treaty was to offer an overview of the obstacles of the psychiatric diseases of childhood and, indeed, it addressed young psychiatrists and pediatricians who had to deal with a certainly not easy, but full of real satisfaction field.

In Italy, between the 19th and 20th centuries, the scientific conception of the child developed: it no longer idealized the childish world as innocent and positive, as in the religious sphere and in the Enlightenment culture, but it was based on an evidence as objective as possible.

The active commitment of the Italian psychologist in defining this new discipline was crowned by the foundation - by De Sanctis himself - of the first pediatric psychiatry hospital ward, consisting of an outpatient clinic and an observation center for children with abnormal behavior.

After the publication in 1906 of some cases of dementia in children aged 6–8, De Sanctis presented in 1908 the report of the observation of a 3-year-old girl to the Regia Accademia di Roma.

The main fact that emerged in the girl's anamnesis was a trauma at 2 years old: he witnessed the death of her mother hit by a tram which caused a growth interruption.

In the wake of the interest that these correspondences have aroused among scholars and to continue the work of enhancing the sources, the entire documentary nucleus has now been rearranged by creating an archival collection called the Fondo Sante De Sanctis.