In search of essential behaviours for diagnosing DSM-5 Autism Spectrum Disorder

Background: Despite initial concerns about the sensitivity of the proposed diagnostic criteria for DSM-5 Autism Spectrum Disorder (ASD), evidence is growing that the DSM-5 criteria provides an inclusive description with both good sensitivity and specificity (e.g. Kent, Carrington et al., 2013). The capacity of the criteria to provide high levels of sensitivity and specificity comparable with DSM-IV-TR, however, relies on careful measurement to ensure that appropriate items from diagnostic instruments map onto the DSM-5 descriptions. Aim: To use an existing DSM-5 diagnostic algorithm (Kent, Carrington et al., 2013) to identify ‘essential’ behaviors sufficient to reliably and accurately diagnose DSM-5 (ASD) across age and ability level. Methods: Highly discriminating, ‘essential’ behaviours were identified from the published DSM-5 algorithm developed for the Diagnostic Interview for Social and Communication Disorders (DISCO). Analyses were run on existing DISCO datasets, with a total participant sample size of 335. Highly discriminating items were identified using chi-square statistics and the predictive validity of the resultant item sets was tested using Receiver Operating Characteristic curves. Finally, sensitivity across age and ability was investigated in a subset of individuals with ASD (n = 190). Results: Study 1 identified a reduced item set (48 items) with good predictive that provided a complete representation of DSM-5 ASD criteria but lacked sensitivity for individuals with higher ability. An adjusted essential item set (54 items; Study 2) had good sensitivity when applied to individuals with higher ability and performance was comparable to the published full DISCO DSM-5 algorithm. Investigation at the item level revealed that the most highly discriminating items predominantly measured social-communication behaviours. Conclusions: This work represents a first attempt to derive a reduced set of behaviours for DSM-5 directly from an existing standardized ASD developmental history interview and has implications for the use of DSM-5 criteria in clinical practice.status: publishe