Clinical observations and neuroscientific evidence tell a similar story: Schizophrenia is a disorder of the self-other boundary

Abstract

The relationship between transdiagnostic, dimensional and categorical approaches to schizophrenia is under debate. We propose that if a categorical diagnosis of schizophrenia makes sense, points of rarity should be observable in causal risk factors, genetic or environmental, and/or the neural systems on which they impact. In our reading, the preponderance of the evidence supports the view that risk factors largely have a pleiotropic effect that is not restricted to schizophrenia. In cross-disorder neuroimaging studies, both structural and functional data likewise largely show transdiagnostic dimensional systems-level alterations, with the possible exception of hippocampal connectivity features linked to genetic risk. There is thus no clear neurobiological evidence to support the categorical construct of schizophrenia. Retaining this approach thus revolves primarily around clinical and pragmatic considerations.