Children who are first diagnosed with ADHD and then with ASD experience a substantial delay in their ASD diagnosis compared to those who are diagnosed with ADHD at the same time or after ASD, a new study has found.
Researchers from Boston Children’s Hospital and Harvard Medical School used data drawn from the 2011-12 US National Survey of Children’s Health, which asked parents to provide the age(s) at which their child received a diagnosis of ADHD and/or ASD.
They then examined the association between a previous diagnosis of ADHD and the age at ASD diagnosis, while controlling for factors known to influence the timing of ASD diagnosis. Approximately 20% of the 1,496 children with a current diagnosis of ASD as reported by parents had first been diagnosed with ADHD.
Children diagnosed with ADHD before ASD were diagnosed with ASD approximately three years after those in whom ADHD was diagnosed at the same time or after ASD. One explanation may be that the symptoms of inattention, hyperactivity and impulsivity are common to ADHD and ASD and that clinicians who diagnose ADHD first are failing to consider whether the child has ASD.
To avoid these potential delays in ASD diagnosis, the researchers suggest clinicians should always consider ASD in young children presenting with ADHD symptoms.
The study appeared in the journal Pediatrics.