Measurable difference between people with autism and people without it has decreased: Study

A recent study has revealed that the measurable difference between people having autism and the rest of the population is diminishing. This may also blur the actual meaning of autism.

The study was published in the journal ‘JAMA Psychiatry’.

Dr Laurent Mottrona, a professor at Universite de Montreal’s Department of Psychiatry, worked with intern Eya-Mist Rodgaard of the University of Copenhagen and four other researchers from France, Denmark and Montreal to review 11 meta-analyses published between 1966 and 2019, with data drawn from nearly 23,000 people diagnosed with autism.

The meta-analyses showed that people with autism and people in the rest of the population exhibit significant differences in seven areas: emotion recognition, theory of mind (ability to understand that other people have their own intentions), cognitive flexibility (ability to transition from one task to another), activity planning, inhibition, evoked responses (the nervous system’s response to sensory stimulation) and brain volume.

They found that, in each of the assessed areas, the measurable difference between people with autism and people without it has decreased over the past 50 years. In fact, a statistically significant dilution in effect size (ranging from 45 per cent to 80 per cent) was noted in five of these seven areas.

“If this trend holds, the objective difference between people with autism and the general population will disappear in less than 10 years,” said Mottron

The diagnostic criteria for autism haven’t changed over the years that the differences have diminished. Instead, Dr Mottron believes that what has changed are diagnostic practices.

Even though Dr Mottron recognises that there is a continuum between people with autism and those without it, he believes that such a continuum could result from the juxtaposition of natural categories. “Autism is a natural category at one end of the socialisation continuum. And we need to focus on this extreme if want to make progress,” he said.

In his opinion, autism studies include too many participants who aren’t sufficiently different from people without autism. In contrast to the generally prevailing scientific belief, Dr Mottron thinks that including more subjects in studies on autism, as it is currently defined, reduces the likelihood of discovering new things about the mechanisms of the disorder. No major discoveries have been made in this field in the last 10 years.

(This story has been published from a wire agency feed without modifications to the text. Only the headline has been changed.)

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First Published: Aug 25, 2019 15:01 IST