title: Automatic sensory information processing abnormalities across the illness course of schizophrenia.
abstract: BACKGROUND
  Deficits in automatic sensory discrimination, as indexed by a reduction in the mismatch negativity (MMN) and P3a event-related potential amplitudes, are well documented in chronic schizophrenia. However, MMN and P3a have not been sufficiently studied early in the course of psychotic illness. The present study aimed to investigate MMN, P3a and reorienting negativity (RON) across the course of schizophrenia.
  
  
  METHODS
  MMN, P3a, and RON were assessed in 118 subjects across four groups: (1) individuals at risk for psychosis (n=26); (2) recent-onset patients (n=31); (3) chronic patients (n=33); and (4) normal controls (n=28) using a duration-deviant auditory oddball paradigm.
  
  
  RESULTS
  Frontocentral deficits in MMN and P3a were present in all patient groups. The at-risk group's MMN and P3a amplitudes were intermediate to those of the control and recent-onset groups. The recent-onset and chronic patients, but not the at-risk subjects, showed significant RON amplitude reductions, relative to the control group. Associations between MMN, P3a, RON and psychosocial functioning were present in the chronic patients. In the at-risk subjects, P3a and RON deficits were significantly associated with higher levels of negative symptoms.
  
  
  CONCLUSIONS
  Abnormalities in the automatic processes of sensory discrimination, orienting and reorienting of attention are evident in the early phases of schizophrenia and raise the possibility of progressive worsening across stages of the illness. The finding that MMN and P3a, but not RON, were reduced before psychosis onset supports the continued examination of these components as potential early biomarkers of schizophrenia.
authors: Mental Illness Research, Education and Clinical Center, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, USA.
authors: C
authors: C
authors: Jahshan
authors: K S
authors: KS
authors: Cadenhead
authors: A J
authors: AJ
authors: Rissling
authors: K
authors: K
authors: Kirihara
authors: D L
authors: DL
authors: Braff
authors: G A
authors: GA
authors: Light
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods; D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001288:Attention / Q000502:physiology; D002908:Chronic Disease; D003072:Cognition Disorders / Q000503:physiopathology; D003430:Cross-Sectional Studies; D004192:Discrimination, Psychological / Q000502:physiology*; D018450:Disease Progression; D004569:Electroencephalography / Q000379:methods; D018913:Event-Related Potentials, P300 / Q000502:physiology*; D005260:Female; D006801:Humans; D007406:Interview, Psychological; D008297:Male; D009483:Neuropsychological Tests; D011930:Reaction Time; D012307:Risk Factors; D012559:Schizophrenia / Q000453:epidemiology / Q000473:pathology / Q000503:physiopathology*; D012565:Schizophrenic Psychology; D012720:Severity of Illness Index; D012919:Social Behavior; D055815:Young Adult