This study investigated the relationship between sleep, gastrointestinal symptoms, challenging behavior, adaptive behavior, and quality of life between children and adolescents with autism spectrum disorder (ASD), with and without attention-deficit/hyperactivity disorder (AD/HD) symptoms. Parents of 118 children and adolescents with ASD completed the Conners Early Childhood Rating Scale-Parent Short Form or the Conners 3-Parent Short Form, Children's Sleep Habits Questionnaire, Gastrointestinal Symptom Inventory, Behavior Problems Inventory-Short Form, Pediatric Quality of Life Inventory and the Vineland Adaptive Behavior Scales, Second Edition. The ASD group and the ASD with AD/HD groups differed significantly in sleep problems, gastrointestinal symptoms, and quality of life. Regressions indicated that AD/HD symptoms accounted for a small proportion of the variance for the differences in sleep problems and quality of life. AD/HD symptoms contribute to the complex needs of individuals with ASD. Research is necessary to investigate how these symptoms exacerbate comorbidities.
Keywords: Autism spectrum disorder; attention-deficit/hyperactivity disorder; challenging behavior; gastrointestinal symptoms; quality of life; sleep problems.