title: An incongruent reality: the N400 in relation to psychosis and recovery.
abstract: BACKGROUND
  Cognitive impairments and delusions are hallmarks of schizophrenia, and are thought to be due in part to abnormalities in semantic priming. The N400, a neural measure of semantic processing, is found to be reduced in schizophrenia. However, it is unclear if individuals with other psychoses (e.g., mood disorders or substance abuse with psychotic features) also show this impairment, and whether N400 reduction relates to real-world functioning and recovery.
  
  
  METHODS
  Eighty-nine individuals from the Suffolk County Mental Health Project, a longitudinal study of first-admission psychosis, and 35 healthy adults were assessed using matched, related, and unrelated picture-word pairs to elicit the N400. Patients' real-world functioning, symptomatology, and recovery were tracked since first hospitalization; EEG assessment was completed during year 15 of the study.
  
  
  RESULTS
  Participants with schizophrenia had slower reaction times and reduced N400 to semantically incongruent stimuli relative to healthy participants. Schizophrenia and other psychoses did not differ on N400, suggesting that N400 abnormalities characterize psychosis broadly. When grouped by recovery status, patients who remained ill had a significantly blunted N400, while those who recovered did not differ from healthy adults. Few patients with schizophrenia achieved recovery; therefore recovery results are limited to the other psychosis group. Furthermore, reduced N400 and increased reaction times correlated with greater psychotic symptoms, worse global assessment of functioning scores, unemployment, and impaired social functioning.
  
  
  CONCLUSIONS
  Abnormalities in the N400 are not specific to schizophrenia; in addition, the N400 may be a useful neural correlate of recovery and real-world functioning across psychotic disorders.
authors.affiliation: Department of Psychology, Stony Brook University, Stony Brook, NY, United States. Electronic address: felicia.jackson@stonybrook.edu.
authors.forename: Felicia
authors.initials: F
authors.lastname: Jackson
authors.affiliation: Department of Psychological Sciences, Purdue University, West Lafayette, IN, United States.
authors.forename: Dan
authors.initials: D
authors.lastname: Foti
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Stony Brook University, Stony Brook, NY, United States.
authors.forename: Roman
authors.initials: R
authors.lastname: Kotov
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Stony Brook University, Stony Brook, NY, United States.
authors.forename: Greg
authors.initials: G
authors.lastname: Perlman
authors.affiliation: Department of Psychiatry, University of California San Francisco, San Francisco, CA, United States.
authors.forename: Daniel H
authors.initials: DH
authors.lastname: Mathalon
authors.affiliation: Department of Psychology, Stony Brook University, Stony Brook, NY, United States.
authors.forename: Greg Hajcak
authors.initials: GH
authors.lastname: Proudfit
mesh_terms: D000328:Adult; D001921:Brain / Q000503:physiopathology*; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006760:Hospitalization; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010775:Photic Stimulation; D011618:Psychotic Disorders / Q000175:diagnosis / Q000503:physiopathology* / Q000628:therapy; D011930:Reaction Time; D011932:Reading; D020127:Recovery of Function / Q000502:physiology*; D012559:Schizophrenia / Q000175:diagnosis / Q000503:physiopathology* / Q000628:therapy; D012660:Semantics; D014796:Visual Perception / Q000502:physiology
keywords: ERP; N400; Psychosis; Recovery; Schizophrenia