Restricted interests and repetitive behaviors (RRBs) are core symptoms of autism spectrum disorder (ASD), and commonly occur in attention-deficit/hyperactivity disorder (ADHD). Little is known about how RRBs manifest in ADHD. We quantified and compared factor structures of RRBs in children with ASD (n = 634) or ADHD (n = 448), and related factors…

Our purpose in this study was to further examine the psychometric properties of the Quality of Life for Children with Autism Spectrum Disorder (QOLASD-C) scale. We first investigated the factor structure and the internal consistency of the scale. The bifactor model showed good fit and strong reliability. Second, we used multiple-indicators…

The disorder of autism is widely recognised throughout the world. However, the diagnostic criteria and theories of autism are based on research predominantly conducted in Western cultures. Here we compare the expression of autistic traits in a sample of neurotypical individuals from one Western culture (UK) and two Eastern cultures (India and…

Three self-report measures of the broader autism phenotype (BAP) were evaluated in terms of their internal consistency, distribution of scores, factor structure, and criterion-related validity in a non-clinical sample. All measures showed a continuous distribution. The SRS-A and BAPQ showed expected sex differences and were superior to the AQ in…

The purpose of this study was to test the factor validity and reliability of the Very Short Form of the Physical Self-Inventory- (PSI-VSF) within a sample of adolescents with mild to moderate Intellectual Disability (ID). A total of 362 ID adolescents were involved in two studies. In Study 1, the content and format scale response of the PSI-VSF…

The factor structure of the Dutch translation of the Autism-Spectrum Quotient (AQ; a continuous, quantitative measure of autistic traits) was evaluated with confirmatory factor analyses in a large general population and student sample. The criterion validity of the AQ was examined in three matched patient groups (autism spectrum conditions (ASC),…