Children with autism who were born in underprivileged neighbourhoods are more likely to exhibit more significant symptoms of attention deficit hyperactivity disorder (ADHD) than those born in more affluent communities, according to a new study led by researchers at the UC Davis MIND Institute.
This groundbreaking study is the first of its kind to explore the relationship between neighbourhood factors and ADHD in both autistic and non-autistic children. The research offers new perspectives on mental health conditions and could play a key role in shaping public policy changes to enhance health equity.
“We discovered that certain neighbourhood factors are closely linked to ADHD symptoms in autistic children”” stated Catrina Club, the primary author of the study. Calub is a postdoctoral researcher working in the laboratory of Julie Schweitzer, who is a professor in the Department of Psychiatry and Behavioral Sciences and the MIND Institute.
“In our study, we found that this effect was only present in autistic children and not in typically developing kids or in kids with other developmental disabilities. It suggests that when autistic children live in neighbourhoods with fewer resources, they tend to exhibit more pronounced ADHD symptoms,” explained Club.
ADHD symptoms may include higher rates of inattention, hyperactivity, and impulsive behavior. It is associated with:
- Challenges in school performance and relationships with friends
- Lower self-esteem and greater risk for anxiety and depression
- Higher potential for substance use disorders and accidents
- Emotional dysregulation and conduct problems
Study expands findings from long-term research
The researchers utilized data from two studies: the long-running Childhood Autism Risks from Genetics and the Environment (CHARGE) study led by Irva Hertz-Picciotto at the MIND Institute and the ReCHARGE follow-up project.
The research team examined 246 children with autism, 85 with developmental delays but not autism, and 193 neurotypical children. They then used the Child Opportunity Index, which utilizes census data to analyze over 30 neighbourhood characteristics. These characteristics include socioeconomics, access to green spaces, single-parent households, and the presence of early childhood education centres.
The index encompasses education, health and environment, and social and economic resources. Higher scores are linked to better childhood health. Of the three domains, the scores for education and social and economic resources were most strongly related to ADHD symptoms.
The analysis showed the Child Opportunity Index scores at birth were a strong predictor for ADHD symptoms in adolescence in autistic children but not in the other groups. Calub noted that the finding was unexpected.
“These results are quite concerning,” Calub said. “Those with both autism and ADHD are already more likely to have additional challenges—behaviorally, cognitively, emotionally, and socially. Being born in a low-income neighbourhood puts them at an even greater disadvantage. This adds to the evidence that more resources are needed for underserved areas and specifically for those who have conditions like autism.”
The need for a larger, more diverse sample
Calub pointed out that more research is needed to determine if the obtained results are conclusive.
apply to a larger group.
“It will be important for future studies to be larger and more diverse. This will help us learn whether neighbourhood conditions might also influence ADHD symptoms in other groups, such as youth without autism, or in Black, Asian, and Native American individuals, who were underrepresented in our sample,” Caleb added.
These findings also provide insights on how to target preventive strategies to reduce the risk of increased ADHD symptoms, as noted by Schweitzer, who was also a co-author on the study.
“ADHD is highly prevalent in the general population and is common in autistic youth. If we can find ways to increase resources in these neighborhoods, we have the potential to improve academic, social, mental, and physical health outcomes, particularly for autistic youth, and also decrease long-term economic costs,” Schweitzer explained.
Calub and Schweizer assert the study’s findings should motivate policymakers to allocate more resources for underserved communities. Furthermore, they suggest that incorporating the Child Opportunity Index and other neighborhood metrics could yield fresh insights for future studies to guide policy.