RI-CART Study Reveals Later Autism Diagnosis for Girls and High Rates of Co-occurring Conditions

Summary: On average, girls on the autism spectrum are diagnosed 1.5 years later than boys. More than half of people with autism experience co-occurring mental health or medical conditions, including ADHD and epilepsy.

Source: Brown University

A new analysis of the first 1,000 participants in the Rhode Island Consortium for Autism Research and Treatment (RI-CART) highlights important trends in autism presentation and diagnosis. The study, published in Autism Research on Jan. 20, examines diagnostic timing, sex differences, and the prevalence of psychiatric and medical comorbidities in a densely sampled U.S. population.

Girls Diagnosed Later Than Boys

The RI-CART analysis found that girls with autism received their first diagnosis about 1.5 years later than boys. Study authors Stephen Sheinkopf and Dr. Eric Morrow attribute this delay, in part, to differences in early language development. Parents and clinicians commonly recognize language delays as an initial sign of autism, and girls in this cohort tended to show stronger language skills than boys, which may make early signs less obvious.

Autism remains substantially more common in males: the RI-CART cohort included more than four times as many boys as girls. However, because the sample is large, researchers were able to examine patterns in girls with greater statistical power. Morrow, an associate professor at Brown University, emphasized the clinical importance of earlier diagnosis.

“The major treatment that has some efficacy in autism is early diagnosis and getting the children into intensive services, including behavioral therapy,” Morrow said. “So if we’re identifying girls later, that may delay their treatments.”

Sheinkopf, an associate professor of psychiatry and pediatrics, called for improved recognition of autism in children whose early language development appears more advanced but who nonetheless struggle with social communication, social play, and adapting to social situations.

“As we improve diagnosis across the full spectrum, we must also rethink early interventions so they are tailored to children who need help with more subtle aspects of social adaptation,” Sheinkopf said. “Treatments should be refined to address individual needs.”

Community-Based, Densely Sampled Cohort

Based at Bradley Hospital in East Providence, RI-CART is a public-private-academic collaboration that brought together Brown University, Bradley Hospital, Women and Infants Hospital, local service providers, and autism community organizations including the Autism Project. By engaging families, clinicians, and community partners, the study enrolled more than 20 percent of pediatric-age individuals with autism statewide.

Participants came from all regions of Rhode Island and underwent thorough in-person assessments. Most had a prior community diagnosis that was later confirmed by the research assessment using standardized behavioral observation tools. The cohort also included individuals with less clear diagnostic results—those with a community diagnosis but no confirmatory research diagnosis, those with a research diagnosis but not a prior community diagnosis, and some who did not meet criteria on either assessment.

“The diagnostically less clear-cut group reflects the complexity clinicians face daily,” Sheinkopf said. “This full range of heterogeneous autism presentation is a unique strength of our study.”

High Prevalence of Co-occurring Psychiatric and Medical Conditions

A major finding of the RI-CART study is the high rate of co-occurring conditions among people with autism. Nearly half of participants reported another neurodevelopmental disorder, such as attention-deficit/hyperactivity disorder (ADHD) or intellectual disability. Additionally, 44.1 percent reported a psychiatric disorder and 42.7 percent reported a neurological condition (including seizures/epilepsy, migraines, or tics). Overall, 92.5 percent reported at least one general medical condition, and nearly one-third reported other behavioral problems.

“These co-occurring conditions need also to be a focus of treatment for patients,” Morrow said.

Sheinkopf added that many people with autism require support for psychiatric and emotional challenges that commonly occur alongside the diagnosis. “These are clinically complex individuals who deserve sophisticated, multidimensional, multidisciplinary care,” he said.

Implications and Future Directions

The RI-CART registry covers a wide age range, from 2 years to nearly 64 years, giving researchers the opportunity to study development and transitions across the lifespan. Sheinkopf and Morrow welcomed the broad collaboration from healthcare providers, community members, and participating families, and they hope the registry will support future studies that improve care and outcomes for people with autism.

“Given that autism is a developmental disorder, the field must focus on longitudinal research—following people over time through key developmental transitions,” Morrow said. “Following children from an early age into adulthood will teach us much more about outcomes and opportunities for intervention.”

Authors, Funding, and Acknowledgments

In addition to Sheinkopf and Morrow, Brown University authors include Carolyn McCormick, Brian Kavanaugh, Danielle Sipsock, Giulia Righi, Lindsay Oberman, Daniel Moreno-De Luca, Ece Gamsiz Uzun, Carrie Best, Beth Jerskey, Pei-Chi Wu, Rebecca McLean, Todd Levine, Hasmik Tokadjian, Kayla Perkins, Elaine Clark, Brittany Dunn, Alan Gerber, Elena Tenenbaum and Thomas Anders. Contributors from the Autism Project include Joanne Quinn and Susan Jewel.

Funding: This work was supported by the Simons Foundation Autism Research Initiative, the Hassenfeld Child Health Innovation Institute at Brown University, the National Institutes of Health (via the National Center for Advancing Translational Sciences), the Clinical and Translational Sciences Award, and the National Institute of Mental Health. Pilot support for RI-CART came from the Carney Institute for Brain Science at Brown, the Norman Prince Neuroscience Institute, and the Department of Psychiatry and Human Behavior.

Source:
Brown University
Media Contact:
Kevin Stacey – Brown University
Image Source:
The image is in the public domain.

Original Research: Closed access
Title: “Autism Heterogeneity in a Densely Sampled U.S. Population: Results From the First 1,000 Participants in the RI‐CART Study.” Stephen Sheinkopf et al., Autism Research. DOI: 10.1002/aur.2261.

Abstract (summary): The RI-CART study established a large, densely sampled U.S. cohort of people with autism spectrum disorder. Using direct behavioral observation and standardized assessment, researchers examined 1,000 participants aged 21 months to 64 years. The cohort likely represents between 20% and 49% of pediatric-age individuals with autism in Rhode Island and matches U.S. Census demographics. Key findings include a later age of first diagnosis for females—possibly related to stronger early language skills—and high rates of psychiatric and medical comorbidities. The study underscores the need for targeted strategies to improve earlier diagnosis in females and to address the broad medical and psychiatric needs of people with autism.