The prevalence of autism has been on the rise globally, with an increase from 0.05% in 1966 to over 2% today. In Quebec’s Montérégie region, the prevalence has increased by 24% annually since 2000. However, Dr. Laurent Mottron questions the reported data and suggests that the line between autism and the general population is becoming increasingly blurry. A recent study published in JAMA Psychiatry supports Dr. Mottron’s findings and is considered significant in the field of psychiatry.
Dr. Mottron and his team conducted meta-analyses that highlighted significant differences between individuals with autism and those without in various areas, including emotion recognition, theory of mind, cognitive flexibility, activity planning, inhibition, evoked responses, and brain volume. They measured the progression of these differences using effect size, which measures the difference in specific characteristics between two subject groups.
Over the past 50 years, the measurable difference between individuals with autism and those without has decreased. There has been a statistically significant reduction in effect size in five of the seven areas studied, indicating a dilution of the differences. However, inhibition and cognitive flexibility did not show significant dilution in effect size. It is predicted that within the next 10 years, the objective differences between people with and without autism may disappear entirely, potentially rendering the current definition of autism less meaningful.
Dr. Mottron believes that changes in diagnostic practices, rather than changes in the criteria for autism, are responsible for the diminishing differences over time. He suggests that three autism diagnostic criteria relate to sociability, and previously, a lack of interest in others was considered a sign of autism. However, with the changing diagnostic practices, it now simply means having fewer friends. Dr. Mottron argues that the term “autism” has been replaced by “autism spectrum disorder” to acknowledge the different forms of the condition.
While some question whether autism exists as a distinct condition, Dr. Mottron asserts that it is fueled by changes in diagnostic practices and that there is a continuum between people with and without autism. He calls for a focus on the extreme end of socialization to make progress in understanding autism, and including participants without autism in studies may reduce the likelihood of new discoveries about the disorder.
In conclusion, the line between autism and non-autism conditions is becoming increasingly blurry. Changes in diagnostic practices, rather than changes in the criteria for autism, have led to a dilution of the measurable differences between individuals with and without autism over the past 50 years. This trend may lead to a disappearance of objective differences within the next decade, potentially trivializing the condition. Dr. Mottron argues for a focus on the extreme end of socialization to better understand autism and cautions against including participants without autism in studies as it may hinder progress in the field.
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