A new study analyzing the first 1,000 participants in the Rhode Island Consortium for Autism Research and Treatment (RI-CART) identifies key trends in the presentation and diagnosis of autism spectrum disorder. The study was published in Autism Research on Monday, Jan. 20.
The first finding was that girls with autism receive a diagnosis, on average, nearly 1.5 years later than boys. This is likely because parents and clinicians tend to notice language delays as the first sign of autism, and girls in the study exhibited more advanced language abilities compared to boys, said study authors Stephen Sheinkopf and Dr. Eric Morrow.
Autism is far more common in boys. The RI-CART study found more than four times as many boys as girls with autism; however, given the large size of the sample, the study was well-powered to evaluate girls with autism. The finding that girls with autism are diagnosed later is clinically important, said Morrow, an associate professor of molecular biology, neuroscience and psychiatry at Brown University.
"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."
The other major finding of the study was that people with autism frequently exhibit co-occurring psychiatric and medical conditions.
Nearly half of the participants reported another neurodevelopmental disorder (i.e., attention-deficit/hyperactivity disorder (ADHD) or intellectual disability), while 44.1 percent reported a psychiatric disorder, 42.7 percent reported a neurological condition (i.e., seizures/epilepsy, migraines, tics), 92.5 percent reported at least one general medical condition and nearly a third reported other behavioral problems.