New evidence on late-diagnosed autism
PARIS — A large international study published in Nature suggests that autism diagnosed later in life could be a distinct form of the condition, different from autism identified in early childhood. The research, carried out by scientists from Denmark, the United States and other countries, focused on whether cases diagnosed after age 10 share the same genetic underpinnings as those diagnosed in early childhood.
Two theories about late-diagnosed autism
Experts highlighted two possible explanations for why some people receive an autism diagnosis later in life. One theory posits that all individuals with autism may share a common genetic background, but subtle or milder symptoms in some people delay recognition until adulthood. The other theory, which the study supports, proposes that late-diagnosed autism could be a different, distinct form within the broader autism umbrella.
What the study found
Using genetic data from thousands of people with autism in Denmark and the United States, the researchers found significant differences between those diagnosed early and those diagnosed later. Importantly, the late-diagnosed group showed genetic patterns more similar to those seen in attention deficit hyperactivity disorder (ADHD) and carried a higher likelihood of mental health conditions such as depression. The findings contribute to the view that autism is highly heterogeneous and that there may be multiple subtypes within the broader spectrum.
Genetics and comorbidities
Dr. Thomas Bourgeron of the Pasteur Institute explained that late-diagnosed individuals appear to share genetic characteristics with ADHD, suggesting overlapping developmental pathways. The study also notes that later-diagnosed autism is associated with increased mental health risks, underscoring the importance of comprehensive care that addresses coexisting conditions in adults.
Implications for diagnosis and treatment
Emeritus Professor Uta Frith of University College London, though not involved in the study, welcomed the work and suggested that continued research could reveal more subgroups within autism. The authors emphasize that clinical practice should move toward personalized care, recognizing that different autism subtypes may require different diagnostic labels, therapies, and supports tuned to an individual’s strengths and challenges.
Context amid public discourse
The study arrives as public discussions about autism have included misinformation, including claims of an epidemic or unfounded links to external factors. Scientists caution that autism is a spectrum with diverse presentations and that science must guide understanding and policy. The goal is to improve outcomes for all individuals on the autism spectrum, regardless of when they are diagnosed.
Bottom line
Autism is a spectrum with potentially multiple underlying pathways. Recognizing that late-diagnosed autism may constitute a different form could improve screening, diagnosis, and tailored support for adults navigating neurodevelopmental differences, ultimately enhancing quality of life and mental health outcomes.
