The importance of complex illness themes, in particular those of mental illness, has already been emphasized in numerous scientific articles regarding the literary work of Georg Büchner. It is particularly evident that Büchner draws on his medical knowledge into the literary text. In Lenz (1835) he experiments like a scientist with themes, images and structures from his scientific sources. This article opens with a comparative discussion of the narrative structures used in psychological case descriptions of the early 1800s and the ones used in Büchner’s Lenz. As the comparison reveals, the use of metaphors referring to mental illness, as well as the use of the narrative expression “es war ihm, als” (it seemed to him as if) characterize the peculiarity of Büchner’s narrative. Furthermore, this article examines the grammatical and rhetorical functioning of the expression “es war ihm, als” and suggests that it should be understood as a medium which introduces a new perspective on critical aspects of Büchner’s contemporary society.