Global Data on Autism Spectrum Disorders Prevalence: A Review of Facts, Fallacies and Limitations

Autism spectrum disorders (ASDs) are a range of neurodevelopmental disorders whose aetiologies are largely unknown. In the past few decades, studies have demonstrated that ASDs occur globally, and that the numbers of recorded cases are rising; however, determining the true prevalence figures is still a major challenge, especially in developing nations. Also, subtle differences in cultural norms might impede timely/accurate diagnosis and categorisation of patients. In this review, we examine the globally-available data on the prevalence of ASD and discuss some of the challenges of data acquisition, with reference to how these may impact the reliability of figures obtained. Some of the facts, fallacies and limitations relating to the presently-available figures are also highlighted.