title: Secondary prevention of schizophrenia: utility of standardized scholastic tests in early identification.
abstract: BACKGROUND
  Given the enormous societal burden of schizophrenia, there has been a growing interest in its prevention during the past decade. Early detection and prompt treatment may improve outcome in schizophrenia. In this study, we examine the value of using pre-morbid cognitive impairment in early detection.
  
  
  METHODS
  Standardized achievement tests Iowa Test of Basic Skills (ITBS) and Iowa Tests of Educational Development (ITED) at Grades 4, 8 and 11 were examined in 70 patients with schizophrenia and 147 comparison subjects without schizophrenia. The majority of comparison subjects later developed another major mental illness such as substance abuse or mood disorder. Receiver operating characteristic curves were used to test the efficiency and accuracy of pre-morbid cognitive tests for differentiating adolescents who will later develop schizophrenia from those who remain well or develop another mental illness.
  
  
  RESULTS
  Although schizophrenia patients had lower mean percentile ranks than comparison subjects in every ITBS/ITED sub-test, these differences were only associated with small increases in risk for schizophrenia. Standardized scholastic tests achieved moderate sensitivity and specificity, and enhanced the detection of schizophrenia by three to five fold. However, positive predictive values were low. ITBS/ITED scores alone cannot be used in screening the general population, given the low positive predictive values.
  
  
  CONCLUSIONS
  Combining ITBS/ITED scores with other risk factors, such as family history, may lead to more efficient early detection. Our findings illustrate the challenges facing the secondary prevention of schizophrenia. Priority should be given to developing efficient and accurate methods of early detection in order to reduce the dangers of making erroneous false positive diagnoses, and to decrease exposure to unnecessary treatment during the testing of early interventions.
authors.affiliation: Department of Psychiatry, University of Iowa College of Medicine, Iowa City, IA 52242, USA. beng-ho@uiowa.edu
authors.forename: Beng-Choon
authors.initials: BC
authors.lastname: Ho
authors.forename: Nancy C
authors.initials: NC
authors.lastname: Andreasen
authors.forename: Peg
authors.initials: P
authors.lastname: Nopoulos
authors.forename: Rebecca
authors.initials: R
authors.lastname: Fuller
authors.forename: Stephan
authors.initials: S
authors.lastname: Arndt
authors.forename: Remi J
authors.initials: RJ
authors.lastname: Cadoret
mesh_terms: D000124:Achievement; D000328:Adult; D003072:Cognition Disorders / Q000175:diagnosis* / Q000523:psychology; D004521:Educational Measurement / Q000379:methods* / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D007361:Intelligence Tests / Q000706:statistics & numerical data; D008137:Longitudinal Studies; D008297:Male; D011237:Predictive Value of Tests; D011594:Psychometrics; D015203:Reproducibility of Results; D012307:Risk Factors; D012559:Schizophrenia / Q000175:diagnosis* / Q000517:prevention & control*; D012565:Schizophrenic Psychology; D012680:Sensitivity and Specificity; D012737:Sex Factors