title: Auditory P300 event related potentials in acute and transient psychosis-Comparison with schizophrenia.
abstract: BACKGROUND
  Limited biological research data are available on acute and transient psychotic disorder (ATPD) vis-à-vis schizophrenia. P300 event related potentials (ERP) have been extensively studied as an important neurophysiological parameter in schizophrenia. However, no P300 ERP studies comparing the two disorders are available. We compared auditory P300 ERP in patients remitted from ATPD with schizophrenia in remission and biologically unrelated healthy controls.
  
  
  METHODS
  In this case-control study design, 25 subjects remitted from ATPD were age-/gender-matched with healthy controls and patients with schizophrenia in remission. Clinical assessment and auditory P300 ERP (amplitude and latencies at central and parietal sites, reaction time) were recorded. The ERP parameters were compared across the three groups.
  
  
  RESULTS
  All three groups showed significant differences in P300 amplitudes and latencies at central and parietal sites. Schizophrenia group differed significantly (p<0.001) from the ATPD group in all the P300 parameters. The ATPD group was found to have lower Pz latency (p<0.05) and lower mean reaction time (p<0.001) as compared to healthy controls.
  
  
  CONCLUSIONS
  The results suggest that P300 could easily distinguish between ATPD and schizophrenia in remission, thus neurophysiologically differentiating the two disorders. Lower P300 latency and reaction time, which indicate hyper-arousability, distinguished ATPD from normal controls, with implications for a better understanding of ATPD.
authors.affiliation: Department of Psychiatry, Post graduate Institute of Medical Education and Research, Chandigarh, India. Electronic address: swapnajit.same@gmail.com.
authors.forename: Swapnajeet
authors.initials: S
authors.lastname: Sahoo
authors.affiliation: Department of Psychiatry, Post graduate Institute of Medical Education and Research, Chandigarh, India.
authors.forename: Savita
authors.initials: S
authors.lastname: Malhotra
authors.affiliation: Department of Psychiatry, Post graduate Institute of Medical Education and Research, Chandigarh, India.
authors.forename: Debasish
authors.initials: D
authors.lastname: Basu
authors.affiliation: Department of Psychiatry, Post graduate Institute of Medical Education and Research, Chandigarh, India.
authors.forename: Manish
authors.initials: M
authors.lastname: Modi
mesh_terms: D000208:Acute Disease; D000328:Adult; D016022:Case-Control Studies; D018913:Event-Related Potentials, P300 / Q000502:physiology*; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D011618:Psychotic Disorders / Q000503:physiopathology*; D012559:Schizophrenia / Q000503:physiopathology*; D055815:Young Adult
keywords: Acute and transient psychosis; Neurophysiology; P300; Schizophrenia