Is delusion inconsequential?

How does delusion influence the patients' behaviors within psychotic disorders? According to an ancient clinical intuition, patients with delusion do not act upon it (delusion would be inconsequent). The authors present how psychiatric and psychopathological literature addressed the issue of acting on delusion since the beginning of the twentieth century in both classical and contemporary works, in various epistemological settings (nosology, philosophy of psychiatry, phenomenology, psychoanalysis, and empirical studies). They propose to consider the notion of "delusional inconsequentiality'', defined as a lack of effect of delusional ideation on behaviors, which cannot be reduced to the negative symptomatology of schizophrenia. The authors highlight the scientific and clinical prospects opened up by taking this trait of delusion into consideration. (C) 2021 Elsevier Masson SAS. All rights reserved.