ABSTRACT
Children ages 6-12 with Autism Spectrum Disorders (ASD) and Attention-Deficit/Hyperactivity Disorder (ADHD) often demonstrate similar challenges in in social skills and externalizing behavior (e.g., Leitner, 2014;May et al., 2018). Although distinct evidence-based intervention strategies for improving social skills and externalizing behavior have been shown to have positive effects for children with ASD (e.g., Wong et al., 2015) as well as children with ADHD (e.g., Fabiano et al., 2014), less is known about how a single evidence-based intervention might differentially affect children with ASD, ADHD, or both (Davis & Kollins, 2012).This study examined behavioral trajectories of children with ASD (n = 39), ADHD (n = 50), or both (n = 28) who participated in Apex Summer Camp prior to the COVID-19 pandemic. Apex is an intensive behavioral intervention modeled after the Summer Treatment Program (Pelham et al., 2012). Hierarchical linear modeling was used to model growth in prosocial and externalizing behaviors during camp, and to test whether diagnosis and pre-camp parent-reported child behavior ratings (i.e., Social Responsiveness Scale and Child Behavior Checklist) predicted growth. Results showed that all children, on average, had significant increases in most prosocial behaviors, but no overall changes in most externalizing behaviors. More importantly, campers with ASD and comorbid ASD and ADHD were rarely different from their counterparts with ADHD alone, though comorbid diagnosis was more often associated with less desirable outcomes. Last, parent pre-intervention behavior ratings were largely not predictive of positive behavior growth but predicted the intercept of some externalizing behaviors. Implications for clinical and school-based practice are discussed. (PsycInfo Database Record (c) 2023 APA, all rights reserved)