Predictability of Self-Report Questionnaires (RAADS-R, AQ-28 and AQ-10) in the Assessment of Autism Spectrum Disorders in Adults

Introduction Although screening instruments for autism spectrum disorders (ASD) are widely used, none have been simultaneously evaluated in an outpatient setting in which the instruments are commonly used. Objectives To... [ view full abstract ]

Introduction
Although screening instruments for autism spectrum disorders (ASD) are widely used, none have been simultaneously evaluated in an outpatient setting in which the instruments are commonly used.

Objectives
To assess if the reported high psychometric properties of screening instruments for ASD in adults also apply to the naturalistic outpatient setting.

Methods
We tested the Ritvo Autism Asperger Diagnostic Scale (RAADS-R) and two short versions of the Autism Spectrum Quotient (AQ), the AQ-28 and AQ-10 in 210 patients referred for psychiatric assessment and 63 controls in six outpatient settings. Assessing clinicians were blind to the RAADS-R and AQ scores. At the end of the study, the clinical diagnosis (ASD or no ASD) was related to the RAADS-R and AQ-scores collected prior to the assessments.

Results
Of the 210 patients, 139 received an ASD diagnosis and 71 received another psychiatric diagnosis. While the clinical groups differed from each other and the control group in their scores on each of these three ASD measures, the percentage correct diagnoses was rather low (RAADS-R 68%, AQ-28 and AQ-10 61%). Both the sensitivity and specificity of each of these instruments was insufficient, where the sensitivity of the RAADS-R was the highest (73%) and the AQ short forms had the highest specificity (70 and 72%).

Conclusions
None of these instruments have a sufficient predictive validity to be used to predict clinical outcome in out-patients settings.