Can we improve the diagnostic efficiency and predictive power of prodromalsymptoms for schizophrenia?

Prodromal symptoms and other variables for a sample of 200 young people who had experienced a first-onset functional psychosis, were analyzed to exami ne their diagnostic efficiency and predictive power in relation to a diagno sis of schizophrenia. Two different techniques were utilized to generate op timal cut-off points for a number of prodromal symptoms, and optimal decisi on rules to maximize diagnostic efficiency. The product of the chance corre cted sensitivity and specificity, or the area under the QROC curve, was use d to assess the predictive efficiency of a number of prodromal variables, D SM-III-R prodromal variables, pre-psychotic deterioration, pre-morbid funct ioning, and prodromal duration. The SPAN technique generated a decision rul e that performed equivalently to the single variable 'duration of prodrome' . Implications of these results for future research are discussed. (C) 2000 Elsevier Science B.V. All rights reserved.