Prospective diagnosis of the initial prodrome for schizophrenia based on the Structured Interview for Prodromal Syndromes: preliminary evidence of interrater reliability and predictive validity.
OBJECTIVE
This study was conducted to determine the interrater reliability and predictive validity of a set of diagnostic criteria for the prodrome of the first episode of schizophrenic psychosis when based on the Structured Interview for Prodromal Syndromes.


METHODS
The subjects were patients referred for evaluation because of a suspected schizophrenia prodromal syndrome. For the reliability study, two to four raters independently diagnosed 18 patients on the basis of face-to-face or videotaped interviews. For the validity study, 6- and 12-month outcome data were collected for 29 patients.


RESULTS
Agreement in differentiating prodromal from nonprodromal patients was 93%. The prodromal features had converted to schizophrenic psychosis for 46% of the prodromal patients at 6 months and for 54% at 12 months.


CONCLUSIONS
In small groups of subjects, these diagnostic criteria for the schizophrenic prodrome and the Structured Interview for Prodromal Syndromes showed promising interrater reliability and predictive validity.
Miller
Tandy J
TJ
Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06520, USA. tandy.miller@yale.edu
McGlashan
Thomas H
TH
Rosen
Joanna Lifshey
JL
Somjee
Lubna
L
Markovich
Philip J
PJ
Stein
Kelly
K
Woods
Scott W
SW
D000328:Adult; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D017063:Outcome Assessment, Health Care; D011237:Predictive Value of Tests; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data*; D015203:Reproducibility of Results; D012559:Schizophrenia / Q000175:diagnosis*; D012565:Schizophrenic Psychology; D012720:Severity of Illness Index; D014743:Videotape Recording