Resurrection of the Follow-Back Method to Study the Transdiagnostic Origins of Psychosis: Comment on: “Timing, Distribution, and Relationship Between Nonpsychotic and Subthreshold Psychotic Symptoms Prior to Emergence of a First Episode of Psychosis”, by Cupo et al.

There has been a major drive in research trying to understand the onset of psychosis. Clinical-high risk (CHR) studies focus on opportunistic help-seeking samples with non-psychotic disorders and a degree of psychosis admixture of variable outcome, but it is unlikely that these represent the population incidence of psychotic disorders. Longitudinal cohort studies of representative samples in the general population have focused on development and outcome of attenuated psychotic symptoms, but typically have low power to detect transition to clinical psychotic disorder. In this issue of Schizophrenia Bulletin, Cupo and colleagues resurrect a time-honored method to examine psychosis onset: the epidemiological follow-back study, modernizing it to fit the research framework of the early intervention era. The authors set out to investigate the hypothesis that psychotic disorder represents the poorest outcome fraction of initially non-psychotic, common mental disorders and present compelling findings, unifying previous opportunistic CHR and representative cohort-based work.