It is difficult to know precisely the history of a functional disease, unlike the natural history of infectious agents, tumour processes or poly-malformative syndromes. In the case of psychiatry, and especially schizophrenia and psychotic disorders, a retrospective look at artistic productions (writings and drawings) makes it possible to reconstitute a whole section of this pathological context. Through four medieval and modern examples, we will see how it is possible to do a paleo-psychiatry: Opicinus de Canistris (14^th c.), the Voynich manuscript (15^th c.), Hieronymus Bosch (15^th-16^th c.), and the Codex Seraphinianus (20^th c.).