Development of the Parent-Rated Anxiety Scale for Youth with Autism Spectrum Disorder.

OBJECTIVE: Anxiety is common in youth with autism spectrum disorder (ASD). There is no accepted outcome measure for anxiety in this population.

METHOD: Following a series of focus groups with parents of youth with ASD, we generated 72 items (scored 0-3). Parents of 990 youth with ASD (age 5-17; 80.8% male youth) completed an online survey. Factor analysis and item response theory (IRT) analyses reduced the content to a single factor with 25 items. Children with a least mild anxiety (N=116; age 5-17; 79.3% male youth) participated in a comprehensive clinical assessment to evaluate validity and reliability of the 25-item Parent-rated Anxiety Scale for ASD (PRAS-ASD).

RESULTS: In the online sample, the mean PRAS-ASD score was 29.04 ± 14.9 (range 0 to 75). Coefficient alpha was 0.93. The IRT results indicated excellent reliability across a wide range of scores with low standard errors. In the clinical sample (N=116), the PRAS-ASD mean was 31.0 +15.6 (range 1-65). Pearson correlations with parent ratings of ASD symptom severity, repetitive behavior and disruptive behavior ranged 0.33 to 0.66 supporting divergent validity of the PRAS-ASD. Pearson correlation with a parent-rated measure of anxiety used in the general pediatric population of 0.83 supported convergent validity. Forty participants (32 boys, 8 girls; mean age of 11.9 + 3.4) returned at Time 2 (mean =12.2 days) and Time 3 (mean = 24.2 days). Intraclass correlation showed test-retest reliabilities of 0.88 and 0.86 at Time 2 and Time 3, respectively.

CONCLUSION: The 25-item PRAS-ASD is a reliable and valid scale for measuring anxiety in youth with ASD.