title: First-episode psychosis: diagnostic stability over one and two years.
abstract: BACKGROUND
  Diagnostic stability is important for daily clinical work and planning of treatment. The aims of this study were to measure diagnostic stability in a clinical epidemiologic sample and to identify markers of change in diagnosis.
  
  
  METHODS
  Diagnostic stability and change were measured in a sample of 301 patients with first-episode psychosis from four national health care sectors in Norway and Denmark at baseline, 1 and 2 years.
  
  
  RESULTS
  Diagnostic stabilities were high for schizophrenia and schizoaffective disorder (85-99%), low for schizophreniform disorder (16-19%), and intermediate for other diagnoses. Diagnostic change from schizophreniform to schizophrenia was frequent in year 1 (72%). Characteristics discriminating schizophreniform patients keeping their diagnosis (i.e. having recovered within 6 months with no relapse) from those developing schizophrenia at 1 year were female gender, better childhood premorbid functioning, shorter duration of untreated psychosis and more severe general psychotic symptoms, especially excitation.
  
  
  CONCLUSIONS
  Findings provide validation for the DSM-IV categories within the schizophrenic spectrum. The limitations of the study were: the raters were not blind to baseline assessments; patients with longer duration of untreated psychosis were more likely to refuse participation; not all patients were assessed at 1- and 2-year follow-up, but the attrition was rather low.
authors.affiliation: Psychiatric Research Unit, Zealand Region Psychiatry Roskilde, Roskilde, Denmark. ulrikhaahr@mail.dk
authors.forename: Ulrik
authors.initials: U
authors.lastname: Haahr
authors.forename: Svein
authors.initials: S
authors.lastname: Friis
authors.forename: Tor K
authors.initials: TK
authors.lastname: Larsen
authors.forename: Ingrid
authors.initials: I
authors.lastname: Melle
authors.forename: Jan Olav
authors.initials: JO
authors.lastname: Johannessen
authors.forename: Stein
authors.initials: S
authors.lastname: Opjordsmoen
authors.forename: Erik
authors.initials: E
authors.lastname: Simonsen
authors.forename: Bjørn Rishovd
authors.initials: BR
authors.lastname: Rund
authors.forename: Per
authors.initials: P
authors.lastname: Vaglum
authors.forename: Thomas
authors.initials: T
authors.lastname: McGlashan
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000465:Algorithms; D003937:Diagnosis, Differential; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011618:Psychotic Disorders / Q000175:diagnosis* / Q000453:epidemiology / Q000523:psychology*; D012559:Schizophrenia / Q000175:diagnosis* / Q000453:epidemiology; D012565:Schizophrenic Psychology; D012720:Severity of Illness Index; D019966:Substance-Related Disorders / Q000453:epidemiology; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult