Being born in a low-income neighborhood increases the risk that children with autism spectrum disorder will have more severe ADHD symptoms, underscoring the need to improve health equity in these communities.
Children with autism who are born in low-income neighborhoods are more likely to show more severe symptoms of attention-deficit/hyperactivity disorder (ADHD) compared with those who grow up in more affluent communities, a new study led by researchers at the MIND Institute at the University of California, Davis, has found.
This is the first time that the study has looked at how neighborhood factors are linked to ADHD in children, both those with autism spectrum disorder and those with typical neurodevelopment. The study offers new insights into mental health conditions and could influence changes in public policies to improve health equity. The findings have been published in the journal JCPP Advances.
“We found that certain neighborhood factors are strongly related to ADHD symptoms in autistic children,” said Catrina Calub, the study’s senior author and a postdoctoral researcher in the lab of Julie Schweitzer, a professor in the Department of Psychiatry and Behavioral Sciences and the MIND Institute.
“In this study, we did not see this effect in typically developing children or those with other developmental disabilities, only in autistic children. This suggests that when autistic children live in less-resourced neighborhoods, they tend to have more pronounced ADHD symptoms,” Calub explained.
ADHD symptoms may include increased levels of inattention, hyperactivity, and impulsive behavior. These symptoms are associated with:
- Difficulties in school performance and relationships with friends.
- Low self-esteem and increased risk of anxiety and depression.
- Increased likelihood of developing substance abuse disorders and having accidents.
- Problems with emotional and behavioral regulation.
- The study extends findings from long-term research.
Increasing neighborhood resources to reduce ADHD risk
The researchers used data from two studies: the CHARGE (Childhood Autism Risks from Genetics and Environment) study led by Irva Hertz-Picciotto at the MIND Institute, and the follow-up ReCHARGE project. CHARGE and ReCHARGE assess how genetics, environment, and other factors influence development from early childhood (2–5 years) through adolescence (8–20 years).
The team studied 246 autistic children, 85 with developmental delays (without autism), and 193 with neurotypical development. They then applied the Children’s Opportunity Index, which uses census data to track more than 30 neighborhood characteristics, including socioeconomic status, green space, single-parent households, and the concentration of early childhood education centers.
The index covers three domains: education, health and environment, and social and economic resources. Higher scores are associated with better child health. Of the three domains, scores in education and social and economic resources were most strongly associated with ADHD symptoms.
“Children with autism and ADHD are more likely to face additional challenges – behavioral, cognitive, emotional and social – and being born in a low-income neighborhood puts them at an even greater disadvantage.”
The analysis showed that Childhood Opportunity Index scores at birth were a strong predictor of ADHD symptoms in adolescence in autistic children, but not in the other groups. “These results are quite concerning,” Calub said. “Those with autism and ADHD are already more likely to face additional challenges – behavioral, cognitive, emotional and social. Being born in a low-income neighborhood puts them at an even greater disadvantage. This reinforces the need for more resources in underserved areas, especially for those with conditions like autism.”
ADHD is highly prevalent in the general population and 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 outcomes, particularly for autistic youth, and also reduce long-term economic costs,” said Julie Schweitzer, professor in the Department of Psychiatry and Behavioral Sciences.
Calub said more research is needed to determine whether the results would apply to a broader group. “It will be important for future studies to be larger and more diverse. That should help us understand whether neighborhood conditions may 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,” she added.
