Early Childhood Aggression in Autistic and Non-Autistic Preschoolers: Prevalence, Topography, and Relationship to Emotional Reactivity.

Objective: Despite heightened rates of aggressive behaviors among older autistic youth relative to non-autistic peers, less is known about these behaviors during early childhood. This study included 3 objectives to address this gap: (1) to establish the prevalence and topography (frequency, severity, type, context) of aggressive behaviors in a large sample of preschool-aged children using a developmentally sensitive parent-report measure; (2) to identify clinical correlates of aggression; and (3) to investigate whether different subgroups of autistic children can be identified based on their profiles of aggression, emotional reactivity, and autism traits. Method: Data were analyzed from parents of 1,199 children 2 to 5 years of age (n = 622 autistic children) who completed the Multidimensional Assessment Profiles Scales (MAPS) aggression subscale and the Emotion Dysregulation Inventory-Young Child (EDI-YC) reactivity subscale. Results: Autistic preschoolers had 2 to 6 times higher odds of experiencing frequent aggression (more days than not) compared with non-autistic preschoolers. Hierarchical multiple regression analyses revealed that autism diagnosis, traits, and suspected and diagnosed attention-deficit/hyperactivity disorder (ADHD) were positively associated with aggression; however, heightened emotional reactivity explained the greatest degree of added variance in aggression total scores. Machine learning clustering techniques revealed 3 distinct subgroups of autistic preschoolers, with cluster membership driven primarily by aggression and reactivity scores, and less so by autism traits. Conclusion: Autistic preschoolers display more frequent parent-reported aggressive behaviors, and emotional reactivity may play an important role in aggressive behavior presentation. Future developmental screening and early intervention tailoring for aggression may benefit from assessing reactivity early in development. Diversity & Inclusion Statement: One or more of the authors of this paper self-identifies as a member of one or more historically underrepresented racial and/or ethnic groups in science. One or more of the authors of this paper self-identifies as a member of one or more historically underrepresented sexual and/or gender groups in science. One or more of the authors of this paper self-identifies as living with a disability. The author list of this paper includes contributors from the location and/or community where the research was conducted who participated in the data collection, design, analysis, and/or interpretation of the work.