Early Childhood Diagnosis of Co-Occurring Developmental Conditions May Prompt Earlier Autism Evaluation

Autistic children often have other neurodevelopmental conditions, such as language delay, motor delay, ADHD, and global developmental delay. However, until now we did not know how common it was for an autistic child to have multiple additional neurodevelopmental conditions, and whether these diagnoses were related to when a child receives their autism diagnosis. This study used North Carolina Medicaid data to examine which neurodevelopmental conditions are most often diagnosed before an autism diagnosis and whether having these conditions is linked to being diagnosed with autism earlier or later. The researchers also explored whether these patterns differed for boys and girls.

The study included 2,694 children who were diagnosed with autism by 8 years of age and were continuously enrolled in North Carolina Medicaid from infancy. Most participants were boys (77%), and researchers examined information about their sex, race and ethnicity, and diagnoses of other neurodevelopmental conditions that occurred before their autism diagnosis.

About 90% of autistic children had at least one other neurodevelopmental condition diagnosed before their autism diagnosis. Language delay was the most common (82%), followed by global developmental delay (52%), motor delay (46%), and ADHD (19%). Children with language delay, motor delay, or global developmental delay were diagnosed with autism several months earlier than children without those conditions. The largest differences were seen when these delays were identified between 1.5 and 2 years of age. ADHD was not significantly linked to earlier or later autism diagnosis.

These findings show that most autistic children experience difficulties with their language, motor skills, or overall development that are evident before their autism diagnosis. Children who are identified early with these developmental delays may receive autism diagnoses sooner, which can help families access supports and services earlier. The results highlight the importance of developmental screening and ongoing monitoring for autism in children with other neurodevelopmental conditions. They also suggest that clinicians should consider the full range of a child’s developmental needs when planning care and interventions.