Comparing temporal event-coding in patients with first-episode psychosis and chronic schizophrenia

Cognitive impairments are a core feature of schizophrenia. It has been suggested that the underlying cause of the cognitive deficits in schizophrenia is an impaired ability to sequence mental activity in time. Various studies have found increased time windows where patients with schizophrenia judge stimuli to appear simultaneously. However, very little is known if these deficits are already present in first-episode psychosis (FEP) or if they develop gradually over time. This study compared the subjective evaluation of temporal structure between healthy controls, chronic schizophrenic and FEP patients using an experimental approach involving judgments of simultaneity of visually presented stimuli. The results suggest that patients required longer delays between stimuli to detect asynchrony, although FEP patients exhibit shorter windows of simultaneity compared to the chronic sample. These data indicate that FEP patients do not appear to have the same impairments in event-coding in time as do chronic patients but show substantial variability.