title: Initial diagnosis and treatment in first-episode psychosis: can an operationalized diagnostic classification system enhance treating clinicians' diagnosis and the treatment chosen?
abstract: OBJECTIVE
  Diagnosis during the initial stages of first-episode psychosis is particularly challenging but crucial in deciding on treatment. This is compounded by important differences in the two major classification systems, International Classification of Diseases, 10th revision (ICD-10) and Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV). We aimed to compare the concordance between an operationalized diagnosis using Operational Criteria Checklist (OPCRIT) and treating clinician-generated diagnosis in first episode psychosis diagnosis and its correlation with treatment prescribed.
  
  
  METHODS
  Operationalized polydiagnostic assessments were conducted on 150 first-episode psychosis patients using OPCRIT. OPCRIT generated ICD-10, DSM-IV and treating clinician diagnoses were compared. The association between these diagnoses and choice of treatment was evaluated.
  
  
  RESULTS
  General agreement between the three classification systems was moderate to good, with kappa values between 0.460 and 0.674. There was a higher frequency of schizophrenia diagnosis in ICD-10 (n = 85) comparing to DSM-IV (n = 45) and similar in clinical diagnosis (n = 76), with moderate to good agreement between classifications (kappa between 0.602 and 0.731). No significant differences were found for ratings of psychotic depressive and manic/bipolar disorders with psychosis, with affective disorders having the higher agreement. Heterogeneous group of 'other disorders' achieved a kappa value from 0.250 (DSM-IV/ICD-10) to 0.566 (DSM-IV/clinical diagnosis).
  
  
  CONCLUSIONS
  Despite the challenges in first-episode psychosis diagnosis, it is possible to have a good agreement between OPCRIT-generated (DSM-IV and ICD-10) diagnoses and clinician based diagnoses, although some differences exist. The choice of psychopharmacological treatment prescribed matches well with these operationalized diagnoses.
authors.affiliation: Lambeth Early Onset Service, SouthLondon and Maudsley NHS Trust, London, UK. ricardo.coentre@netc.pt
authors.forename: Ricardo
authors.initials: R
authors.lastname: Coentre
authors.forename: Pablo
authors.initials: P
authors.lastname: Blanco
authors.forename: Silvina
authors.initials: S
authors.lastname: Fontes
authors.forename: Paddy
authors.initials: P
authors.lastname: Power
mesh_terms: D000293:Adolescent; D000328:Adult; D039721:Diagnostic and Statistical Manual of Mental Disorders; D042241:Early Diagnosis; D005260:Female; D006801:Humans; D038801:International Classification of Diseases; D008297:Male; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data*; D011618:Psychotic Disorders / Q000175:diagnosis* / Q000188:drug therapy; D011619:Psychotropic Drugs / Q000627:therapeutic use
chemical_list: D011619:Psychotropic Drugs