While scientists aren’t sure about what causes autism, it’s likely that both genetics and environment play a role. Amy Daniels, the assistant director for public health research at Autism Speaks, a New York City-based advocacy group, says she agrees that a significant cause in the reported increases result from changes in diagnostic methods. Daniels adds that the findings in this new study are “consistent with past research documenting non-causal factors such as increased autism awareness.”
To conduct the study, researchers collected data on nearly 700,000 children born between 1980 to 1991 and followed them until they were either diagnosed with autism, died or emigrated, or the end of 2011, whichever came first. Almost 4,000 from that research group were diagnosed with autism, with most after 1995 when diagnostic criteria changed. The study was published online November 3 in JAMA Pediatrics.