Children with ADHD are more likely to have autism traits than those without ADHD according to a new study completed at Massachusetts General Hospital, Harvard Medical School and SUNY Upstate Medical University.

The study looked at 469 children of which 242 had ADHD and 227 did not between the ages of 8 to 14 years old. None of the children had been diagnosed with autism but researchers were interested in finding out how many exhibited signs of autism, such as social difficulties.

According to the study, 18 percent of those with ADHD showed autism traits, as compared to less than 1 percent of those without ADHD. The researchers pointed out that showing autism traits does not mean that a child is on the autism spectrum (ASD).

Autism is a developmental disorder characterized by difficulties with social interaction and communication as well as repetitive behaviors. Approximately one in every 88 children have ASD. Signs of autism usually appear between the ages of two and three years old, although it is present from birth. Speech delays and difficulties interacting with others are some of the early warning signs of autism.

The recent study indicated that the children with ADHD who also had autism traits were more likely to:

• Be shunned by peers
• Have problems with siblings
• Get into fights

Overall, researchers found these children to be more severely impaired than those with ADHD but without ASD traits. Amelia Kotte, Ph.D. one of the researchers indicated that it is important to identify children with autism traits to modify treatment, especially in the area of social skills.

Misdiagnosing Autism as ADHD

The three main symptoms of ADHD, inattention, hyperactivity and impulsiveness, can all be found in children with autism as well. This confusion may cause some children with autism to be misdiagnosed with ADHD according to a study completed at Penn State College of Medicine and published in the journal Research in Autism Spectrum Disorders.

Researchers of this study point out, however, that while the main symptoms of ADHD can be a part of autism, symptoms of autism are not common in children with ADHD. Because of this, the two disorders can be easily distinguished.

Another study showed that while sustained attention scores were similar in children with ADHD and ASD, cognitive-attentional tasks, such as rapid letter naming performance, did show clear differences in children with ADHD from those with ASD. Researchers from Baylor University, who completed this study, indicate that these types of tests may help doctors distinguish the two disorders.

References:

"Autism and ADHD: Overlapping and Discriminating Symptoms," 2012, Susan Dickerson Mayes et al, Research in Autism Spectrum Disorders

"Autistic Traits in Children With and Without ADHD," 2013, Amelia Kotte, Ph.D. et al, Pediatrics

"The Difference Between Autism and ADHD Is in the Eye of the Cognitive Task?" 2011, June, Lucy Barnard-Brak, Personality and Individual Differences