The history of psychiatric hospitals, and of psychiatry in general, is also the history of the practices and tools used to control the behavior of the mentally ill. It is necessary to strive to place these artifacts in their cultural and historical framework: however, past and even recent abuses cannot be ignored, and it can be said that the way in which the problem is addressed is the figure of the level of civilization of a entire society.

Photography seemed to give an answer to psychiatry's need to anchor its hypotheses and certainties to the image, to the body. The British doctor Morison, as early as 1840, was comparing images of the same subject, sick and then cured. The neurologist Charchot photographed the sick to study the relationship between disease and somatic traits, on the basis of theories similar to those of Lombroso. At the end of the 19th century, the director Tamburini introduced photography to the San Lazzaro, which also became a model for this reason. The instruments and 1500 images of patients, buildings and scenes of life and work are preserved.

In the era of positivistic psychiatry, the San Lazzaro became a model for scientific research as well. Luigi Biagi introduced medical records, while with Carlo Livi in 1874 the San Lazzaro became the seat of the Psychiatric Clinic of the University of Modena, until 1908. Augusto Tamburini increased the number of scientific laboratories (histology, anthropology, experimental psychology, chemical analysis, electrotherapy) and museum collections. Many of the most important future Italian psychiatrists studied and worked in Reggio.

In the San Lazzaro archives there are about 8000 works produced by the former inmates, in particular during the painting ateliers opened as early as the 19th century and active until closing. There is also a large production of children hospitalized in the Marro school colony, where drawing was one of the subjects of study.

In the archives of San Lazzaro there are testimonies of every aspect of life and management, including administrative, of the former psychiatric hospital, a heritage of great importance in Italy. The main documentation is represented by medical records (from the 1870s): many also keep writings or drawings of patients, in addition to personal information and the clinical diary. From the previous period there remain brief news or correspondences between the director and family members.