Low-level temporal coding impairments in psychosis: preliminary findings and recommendations for further studies

The authors investigated whether difficulties with temporal event coding, previously reported in patients with schizophrenia, are already present during first-episode psychosis (FEP). In this experiment, the subjective judgments of the simultaneity of visually presented stimuli were compared between 11 healthy controls, 9 patients with chronic schizophrenia (CSZ), and a sample of 11 FEP patients. Participants were asked to indicate whether 2 vertical bars appeared at the same time or at different times on a computer monitor. CSZ patients' thresholds were elevated, and the FEP sample showed higher thresholds relative to controls. Although preliminary, these findings indicate a generalized disturbance in event-structure coding at early stages of psychosis and question the specificity of its disturbance. Considering the proposed relationship between event-structure coding and the experience of time in general, this study recommends that future studies refocus on psychosis in general, rather than on schizophrenia as a particular case of abnormal temporal processing. In addition, it is suggested that the relevant psychopathology will be best determined by means of a comprehensive analysis of low-level temporal coding performance in different types of psychosis.