Attention-deficit hyperactivity disorder (ADHD) is common among autistic people. Less is known about the behavioral characteristics of children who have both conditions when they are toddlers.
A recent study led by associate professor Naomi Davis, PhD, asked caregivers to answer questions about their toddlers’ behavior, including whether they noticed signs of autism or ADHD. The children were then followed over several years. Some were diagnosed with autism only or autism plus ADHD.
When children had both conditions, caregivers reported that their toddlers had higher levels of autistic traits and ADHD-related behaviors. Scores on a commonly used autism screener were higher, and caregivers also reported needing more support in caring for their child. This study suggests that the co-occurrence of ADHD with autism affects children’s development as early as toddlerhood.
This paper was published in the Journal of Child Psychology and Psychiatry in 2025. This work was supported by grants from the National Institutes of Health, including the Autism Center of Excellence and National Center for Advancing Translational Sciences grants.
Davis, N. O., Lerebours, R., Aiello, R. E., Carpenter, K. L. H., Compton, S., Franz, L., Kollins, S. H., Sabatos‐DeVito, M., Spanos, M., & Dawson, G. (2025). Behavioral characteristics of toddlers later identified with an autism diagnosis, ADHD symptoms, or combined autism and ADHD symptoms. Journal of Child Psychology and Psychiatry, 66(2), 214–224. https://doi.org/10.1111/jcpp.14050