Autism Spectrum Disorder: ADHD Behavior May Mask Autism & Delay Crucial Diagnosis [New Study]

A recent study published online has discovered that kids with Autism Spectrum Disorder (ASD) might be incorrectly diagnosed with ADHD.

According to HealthDay, the study has found that symptoms of attention-deficit hyperactivity disorder,or ADHD, may overshadow or "mask" autism spectrum disorder, or ASD.

The researchers said that this overshadowing can create a significant delay in the accurate diagnosis of the condition. It took an average period of three years longer to properly diagnose ASD in kids who were thought to be just having ADHD.

Study author Dr. Amir Miodovnik, developmental pediatrician at Boston Children's Hospital, said: "It's been shown the earlier that you implement these therapies for autism, the better children do in terms of outcomes."

"Three years is a significant amount of time for the kids to not be receiving therapy," he added.

The study was published online on Sept. 14, and will be in the October print of Pediatrics.

According to the study authors, inattention, hyperactivity and impulsivity are core features of ADHD. However, kids with ASD often show the same symptoms, and may be diagnosed with ADHD first. Researchers investigated the length of time that passes between an initial ADHD diagnosis, and a more accurate diagnosis with autism.

To do that, the researchers looked at data from the National Survey on Children's Health on 2011 to 2012, involving nearly 1,500 children. The survey asked parents regarding the age of their kids when diagnosed with ADHD and/or ASD. 

The researchers found that more than two out of five kids diagnosed with both conditions were diagnosed with ADHD first. Most of the kids diagnosed with ADHD were eventually diagnosed with ASD at age six.

It was also found that kids initially diagnosed with ADHD were 17 times more likely to be diagnosed with ASD past age six.

The kids initially diagnosed with ADHD were also 30 times more likely to be diagnosed with autism after age six, compared to those diagnosed with both conditions, or those diagnosed with autism first and then ADHD later.

Dr. Daniel Coury, chief of developmental and behavioral pediatrics and Nationwide Children's Hospital, said that the results indicate doctors rushing to apply a diagnosis that's too early.

"In fact, these children may have a neurodevelopmental problem that is going to change over the next few years, and will be much more apparent at 4 or 5 years than it is at 2," said Dr. Coury. "We don't usually make a diagnosis of ADHD in 3- and 4-year-old children. If we're making a diagnosis at that early age, maybe we should be thinking about a developmental disorder that is more common for that age group, like autism."