Why is autism increasing? Scientists are converging on an unglamorous answer
Autism diagnoses have skyrocketed over the past few decades, prompting a debate among scientists. Is the biological rate of autism actually rising, or is society simply naming the condition more frequently?
The growing number of autism diagnoses is a widely recognized phenomenon. In the United States, a study published in the Journal of Autism and Developmental Disorders found a substantial increase in autism diagnoses among children and adolescents from 2013 to 2022. By the end of the study period, the researchers estimated that nearly four percent of children in the surveyed group had received an autism label.
Globally, researchers often use systematic reviews to estimate the prevalence of autism. One such review concluded that about one percent of people in the populations studied have autism, although this figure spans a wide range from 1.09 to 436 per 10,000 people due to differences in study designs and methodologies. Another review found a slightly lower pooled prevalence but noted an overall increase over time, attributing this variation to differences in study methods.
When examining specific primary care systems, the growth in autism diagnoses is significant. Research from England and Northern Ireland revealed a staggering 787 percent increase in recorded autism diagnoses between 1998 and 2018. Interestingly, the average age of diagnosis shifted upwards during this period, from 9.6 years to 14.5 years, challenging the assumption that rising numbers are due to earlier detection in childhood.
A key observation from a study in Sweden’s registry-based health system is the changing demographics of those receiving diagnoses. While boys were historically diagnosed at higher rates, the male-to-female ratio began to invert in late adolescence and early adulthood, with more females than males diagnosed between the ages of 15 and 24.
This trend suggests a potential catch-up effect, where girls were historically underdiagnosed, and the medical field is now correcting that oversight. Alternatively, some researchers propose that the increasing rates could be due to a lowering of the threshold for diagnosis, leading to more people meeting the criteria for an autism label.
Written by urgent.news from PsyPost's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
