Psychometric characteristics of the AQ-Adolescent in autistic and non-autistic adolescents

The Autism Spectrum Quotient (AQ) measures autistic traits in children and adults. The adolescent version of the AQ is understudied. We analyzed the factor structure, informant- and sex differences, and clinical utility of the AQ adolescent in 1) parent reports from adolescents in the general population (GenPop; AQ50; N = 465), parent reports from autistic adolescents (Netherlands Autism Register, NAR; AQ28 [Hoekstra et al., 2011]; N = 284), and parent- and self-reports of autistic and non-autistic adolescents (MATCH; AQ50; N = 84). The tested AQ-Adult factor models (Hoekstra et al., 2011; Murray, Allison et al., 2017; Murray, McKenzie et al., 2017; Russell-Smith et al., 2011), showed an acceptable fit in the GenPop sample, and the bi-factor AQ28-Hoekstra (Murray et al., 2011) fitted the NAR sample acceptably. On the AQ28-Hoekstra, autistic adolescents scored lower whereas non-autistic adolescents scored higher than their parents (MATCH), and males scored higher than females on several factors (GenPop, NAR). Moreover, this factor model appeared invariant among autistic and non-autistic groups. Two cut-off scores were evaluated with ROC analyses for parent reports. Given the informant differences, these cannot be applied to self-reports. In conclusion, the AQ28-Hoekstra reliably measures autistic traits in adolescents with and without autism. Combining parent and self-report seems most informative.