title: Differences between first episode schizophrenia and schizoaffective disorder.
abstract: BACKGROUND
  The diagnostic and clinical overlap between schizophrenia and schizoaffective disorder is an important nosological issue in psychiatry that is yet to be resolved. The aim of this study was to compare the clinical and functional characteristics of an epidemiological treated cohort of first episode patients with an 18-month discharge diagnosis of schizophrenia (FES) or schizoaffective disorder (FESA).
  
  
  METHODS
  This study was part of the larger First Episode Psychosis Outcome Study (FEPOS) which involved a medical file audit study of all 786 patients treated at the Early Psychosis Prevention and Intervention Centre between 1998 and 2000. Of this cohort, 283 patients had an 18-month discharge diagnosis of FES and 64 had a diagnosis of FESA. DSM-IV diagnoses and clinical and functional ratings were derived and validated by two consultant psychiatrists.
  
  
  RESULTS
  Compared to FES patients, those with FESA were significantly more likely to have a later age of onset (p=.004), longer prodrome (p=.020), and a longer duration of untreated psychosis (p<.001). At service entry, FESA patients presented with a higher illness severity (p=.020), largely due to the presence of more severe manic symptoms (p<.001). FESA patients also had a greater number of subsequent inpatient admissions (p=.017), had more severe depressive symptoms (p=.011), and higher levels of functioning at discharge.
  
  
  CONCLUSIONS
  The findings support the notion that these might be considered two discernable disorders; however, further research is required to ascertain the ways and extent to which these disorders are discriminable at presentation and over time.
authors.affiliation: Orygen Youth Health Research Centre, Melbourne Australia; Centre for Youth Mental Health, The University of Melbourne, Australia. Electronic address: smcotton@unimelb.edu.au.
authors.forename: S M
authors.initials: SM
authors.lastname: Cotton
authors.affiliation: Psychosis Early Detection and Intervention Centre (PEDIC), Department for Psychiatry and Psychotherapy, Centre for Psychosocial Medicine, University Medical Center Hamburg-Eppendorf, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Lambert
authors.affiliation: University Hospital of Child and Adolescent Psychiatry, University of Bern, Switzerland.
authors.forename: B G
authors.initials: BG
authors.lastname: Schimmelmann
authors.affiliation: Orygen Youth Health Research Centre, Melbourne Australia; Centre for Youth Mental Health, The University of Melbourne, Australia.
authors.forename: A
authors.initials: A
authors.lastname: Mackinnon
authors.affiliation: School of Psychology, Australian Catholic University, Australia.
authors.forename: J F M
authors.initials: JFM
authors.lastname: Gleeson
authors.affiliation: Orygen Youth Health Research Centre, Melbourne Australia; Centre for Youth Mental Health, The University of Melbourne, Australia; Deakin University, Geelong, Australia; Florey Institute for Neuroscience and Mental Health, Parkville, Australia.
authors.forename: M
authors.initials: M
authors.lastname: Berk
authors.affiliation: Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia.
authors.forename: L
authors.initials: L
authors.lastname: Hides
authors.affiliation: Orygen Youth Health Research Centre, Melbourne Australia; Centre for Youth Mental Health, The University of Melbourne, Australia.
authors.forename: A M
authors.initials: AM
authors.lastname: Chanen
authors.affiliation: Centre for Clinical Research, University of Queensland, Brisbane, Australia.
authors.forename: J
authors.initials: J
authors.lastname: Scott
authors.affiliation: Psychosis Early Detection and Intervention Centre (PEDIC), Department for Psychiatry and Psychotherapy, Centre for Psychosocial Medicine, University Medical Center Hamburg-Eppendorf, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Schöttle
authors.affiliation: Orygen Youth Health Research Centre, Melbourne Australia; Centre for Youth Mental Health, The University of Melbourne, Australia.
authors.forename: P D
authors.initials: PD
authors.lastname: McGorry
authors.affiliation: Treatment and Early Intervention in Psychosis Program (TIPP), Département de Psychiatrie CHUV, Université de Lausanne, Clinique de Cery, 1008 Prilly, Switzerland.
authors.forename: P
authors.initials: P
authors.lastname: Conus
mesh_terms: D000293:Adolescent; D000328:Adult; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D017063:Outcome Assessment, Health Care; D011569:Psychiatric Status Rating Scales; D011618:Psychotic Disorders / Q000175:diagnosis* / Q000453:epidemiology; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012559:Schizophrenia / Q000175:diagnosis* / Q000453:epidemiology; D012720:Severity of Illness Index; D016896:Treatment Outcome; D055815:Young Adult