Schizophrenia Spectrum Disorders in Relation to the Totality of Psychosis: From First Episode to Long-Term Outcome

Abstract

"Schizophrenia spectrum disorders", however broadly defined, still fail to capture lame tranches of psychotic illness whose epidemiological, psychopathological and pathobiological characteristics are likely important for holistic understanding of psychosis. We outline preliminary findings from the Cavan-Monaghan First Episode Psychosis Study (CAMFEPS) that suspends a priori diagnostic criteria, incepts "all" cases of first episode psychosis on an epidemiologically complete basis, follows cases prospectively over several years and evaluates the extent to which putative post hoc diagnostic distinctions are actually sustained or refuted by the data. Findings from CAMFEPS elaborate a dimensional as distinct from a categorical concept of psychotic symptomatology. What we currently diagnose operationally as schizophrenia/"schizophrenia spectrum disorders" may constitute not a discrete entity/collective but, rather, a domain characterised by certain epidemiological, psychopathological, pathobiological and functional characteristics; the boundaries of this domain appear arbitrary and in continuity with other operational psychotic and non-psychotic, particularly affective diagnoses and, perhaps, with the limits of "normal" adult human behaviour that include non-clinical, psychotic-like experiences.