Children with attention-deficit hyperactivity disorder (ADHD) often exhibit autistic traits, which can lead to even greater problems with socialization, according to new research presented at the 26th European College of Neuropsychopharmacology (ECNP) Congress.

Previous research has shown that children with autism spectrum disorder (ASD) often also have a diagnosis of ADHD. This new study suggests that the reverse may also be true.

“Twin, family, and linkage studies indicate that [ADHD and ASDs] share a portion of their heritable etiology,” wrote the investigators.

“These findings raise the possibility that some children with ADHD may manifest symptoms of autism even in the absence of a full-fledged disorder,” they add.

The research, which involved 469 children, showed that significantly more of those with ADHD had autistic traits (ATs) compared with children without ADHD. Furthermore, the group with both ADHD and ATs had significantly more psychopathologic, neuropsychological and interpersonal deficits, as well as more emotional dysregulation.

“We showed that some children who do not fulfill the criteria for autism have a lot of similar social difficulties and interpersonal dysfunction. That might be something that’s important to recognize,” said lead researcher Joseph Biederman, M.D.

“I would tell clinicians to pay attention to this possibility. It represented about 20 percent of our children with ADHD,” said Biederman, of Massachusetts General Hospital in Boston and the Department of Psychiatry at Harvard Medical School.

The researchers said that identifying ADHD-AT children “heralds the opportunity for early recognition” and for individualized interventions.

For the study, researchers enrolled 242 kids with ADHD and 227 kids without the disorder (mean age, 11.3 years; 99 percent white). None of the participants had been diagnosed with ASD.

“We have been aware for a long time that some of those with ADHD have behaviors that look differently than what you would expect. They do not have a lot of social wisdom and have difficulties interacting, even though they do not fulfill criteria for autism,” said Biederman.

“I’m a researcher who also sees patients. And this is an issue that we have not yet really put our finger on,” he added.

Results showed that 18.18 percent of the children with ADHD had a positive AT profile compared to 0.87 percent of those without ADHD.

Although there were no significant differences in ADHD core symptoms between the ADHD-AT subgroup and the ADHD-only subgroup, the first subgroup did have significantly higher rates of being clumsy and of fighting with and rejection by others.

The ADHD-AT subgroup also had much higher rates of social dysfunction compared with the healthy control group and compared with the ADHD-only subgroup; and they had significantly higher rates of severe emotional problems.

In addition, the ADHD-AT subgroup had significantly more disruptive behavior, mood, multiple anxiety, and language disorders than did either of the other groups.

“Findings reveal that ATs are present in children with ADHD and that their presence heralds a significantly more compromised clinical presentation,” said the investigators.

Some of the results have been published in the journal Pediatrics.

Source: 26th ECNP Congress

ADHD Kids Often Show Autistic Traits