Autism diagnosed later in life could be different form
A large new study suggests that people diagnosed with autism later in life may have a different form of the condition than those diagnosed during childhood. The research, published Wednesday, comes amid widespread misinformation about autism in the United States, including claims by former President Donald Trump and Health Secretary Robert F. Kennedy Jr. that there is an "epidemic" of autism cases and unfounded links to vaccines or paracetamol.
The study supports the idea that the term “autism” encompasses multiple phenomena affecting people in distinct ways. Researchers sought to determine whether there are differences between cases identified in early childhood and those diagnosed after age 10. Historically, autism was considered a childhood condition, but diagnostic criteria have broadened in recent decades, resulting in more diagnoses among older individuals.
The research team outlined two possible explanations for the observed differences. One theory is that all individuals with autism share a similar genetic profile, but some are not diagnosed early because their symptoms are subtle or mild, becoming more apparent later. The alternative theory is that childhood and later-onset autism represent distinct forms of the condition. The study’s findings lend support to the latter hypothesis.
By comparing the genetic profiles of thousands of individuals with autism in Denmark and the United States, researchers identified significant genetic differences between those diagnosed in childhood and those diagnosed later. “People diagnosed with autism later in life are genetically more similar to those with attention deficit hyperactivity disorder (ADHD),” said Thomas Bourgeron, a co-author and researcher at France’s Pasteur Institute.
The study also found that individuals diagnosed later are at greater risk for mental health conditions, including depression. Bourgeron emphasized the diversity within the autism spectrum, highlighting the need for care tailored to each patient’s specific needs.
Uta Frith, an emeritus professor of cognitive development at University College London who was not involved in the study, said the findings raise hope that even more subgroups within autism will eventually be recognized, each receiving a suitable diagnostic label. She added, “If there is talk about an ‘autism epidemic,’ a ‘cause of autism,’ or a ‘treatment for autism,’ the immediate question must be: which kind of autism?”
Overall, the research underscores the complexity of autism and challenges the notion of a single, uniform condition, pointing instead to multiple, genetically and clinically distinct forms that require individualized understanding and care.
