DIAGNOSING AUTISM - ANALYSES OF DATA FROM THE AUTISM DIAGNOSTIC INTERVIEW

Results from ROC curves of items from two scales, the Autism Diagnosti c Interview (ADI) and Autism Diagnostic Interview-Revised (ADI-R), ope rationalizing DSM-IV criteria for autism are presented for 319 autisti c and 113 other subjects fr om 8 international autism centers. Analyse s indicate that multiple items were necessary to attain adequate sensi tivity and specificity if samples with varying levels of language were considered separately. Although considering only current behavior was generally sufficient when a combination cutoff and additive model was employed, predictive power was highest when history was taken into ac count. A single set of criteria, as operationalized when individually structured questions in the ADI/ADI-R, was effective in differentiatin g autism from mental handicap and language impairment in subjects with a range of chronological ages and developmental levels.