title: Low-level temporal coding impairments in psychosis: preliminary findings and recommendations for further studies.
abstract: 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.
authors.affiliation: Department of Psychiatry, Trinity College Dublin, Dublin, Republic of Ireland. heike.schmidt@tcd.ie
authors.forename: Heike
authors.initials: H
authors.lastname: Schmidt
authors.forename: John
authors.initials: J
authors.lastname: McFarland
authors.forename: Mohamed
authors.initials: M
authors.lastname: Ahmed
authors.forename: Colm
authors.initials: C
authors.lastname: McDonald
authors.forename: Mark A
authors.initials: MA
authors.lastname: Elliott
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007600:Judgment / Q000502:physiology*; D008297:Male; D009483:Neuropsychological Tests; D010775:Photic Stimulation; D011618:Psychotic Disorders / Q000175:diagnosis / Q000523:psychology*; D012565:Schizophrenic Psychology; D013998:Time Perception / Q000502:physiology*