This article was originally published 14 May 2017, based on preliminary data presented at the 2017 International Meeting for Autism Research in San Francisco, California. We have updated the article following publication of the study 12 August 2018 in Autism Research1. Updates appear below in brackets.
Social difficulties appear to wane as toddlers with autism mature into young adults, perhaps due in large part to improvements in language ability. Researchers presented the unpublished results yesterday at the 2017 International Meeting for Autism Research in San Francisco, California.
However, the findings do not mean that these individuals no longer have autism, the researchers caution.
“There’s a lot of desire to talk about improvement or decreased severity, but I worry a little that that may be a little misleading,” says Vanessa Hus Bal, assistant professor of psychiatry at the University of California, San Francisco, who presented the findings. “These individuals continue to have autism diagnoses.”
One shortcoming of the study is that it is based on assessments of autism features using a diagnostic test developed for children. This highlights the need for techniques that are designed specifically for adults — particularly those who have well-developed language skills.
“The symptoms that we are using to diagnose children may not be the best markers for autism in adults,” Bal says. “We need to identify what symptoms characterize autism in adulthood and develop new instruments.”
The researchers explored how autism features and language abilities changed over time in  participants, nearly all of whom were diagnosed with autism at age 2. They assessed most of the same children again at ages 3, 5, 9 and .
The team split the children into three groups, all roughly the same size, based on their language skills at age 3 and . One group had delayed language at 3 and remained minimally verbal at ; the second group had delayed language at 3 but developed speech by ; the third group was verbal at both ages.
The researchers analyzed the children’s social and communication difficulties at each age using data from the Autism Diagnostic Interview-Revised, a set of parent reports. They looked at how the severity of these difficulties varied over time in each of the three groups.
Overall, social communication difficulties eased with age in the group of children with fluent speech by age 3. They also waned in the children who acquired language by age , albeit at a slower rate. The problems remained relatively stable in the minimally verbal group, however.
Language ability affects some aspects of social communication more than others. For example, communicative gestures such as pointing and nodding improve with age regardless of language ability. By contrast, showing attention to others and offering comfort improve more with age in those who speak than in those who do not.
The findings suggest that researchers need to account for changes in language ability when evaluating autism features in people as they age. Bal’s team is developing an instrument for assessing autism traits in adults.
For more reports from the 2017 International Meeting for Autism Research, please click here.