The Secretary of the US Department of Health & Human Services (HHSS) recently claimed that US estimates of the prevalence of autism confirmed the existence of an autism epidemic. Furthermore, HHSS asserted that the autism epidemic was driven by an environmental toxin which he promised to find in the following months. These claims are contradicted by studies showing that progress in the understanding, detection, diagnosis and management of autism have fueled the increasing prevalence. HHSS statements are also in sharp contrast with the opinion of scientists who have monitored the upward trend in autism prevalence in the US and worldwide. In this Commentary, we address sequentially each misconception and misinterpretation proffered by HHSS. We show that changes in the definition of autism, in diagnostic criteria and practices, in case ascertainment in surveys, the inclusion of less severe forms of autism and other contextual factors such as improved awareness, de-stigmatization, advocacy, improved access to service and better insurance coverage have all converged in increasing the prevalence of autism and that presenting the rise on autism prevalence as an epidemic is misleading. Furthermore, given the strong heritability of autism, its genetic and phenotypic heterogeneity and the paucity of leads on environmental risk, the promise to find an environmental toxin causally related to autism in upcoming months appears at best preposterous. We warn about the return of false theories and already debunked hypotheses on the etiology of autism when empirical data are ignored, scientific methodology is dismissed and experts' opinions disdained.
Keywords: Autism; Diagnosis; Epidemiology; Prevalence; Survey; Time trends.
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