New findings on late-diagnosed autism
Autism diagnosed later in life may represent a distinct form of the condition, according to a large international study published in Nature. Researchers compared genetic data from thousands of individuals diagnosed with autism in early childhood with those diagnosed much later, often after age 10. The results challenge the traditional view that autism is a single, uniform disorder and instead support the idea that the umbrella term autism encompasses multiple phenotypes with different genetic underpinnings and clinical presentations.
Until recently, autism was primarily identified in young children. As diagnostic practices broadened, more people—including adults—were formally diagnosed. The study sought to answer a core question: do late-diagnosed cases simply share the same biology as early-diagnosed cases but are detected later, or are they fundamentally different?
Two explanations in focus
The researchers outlined two plausible theories. The first posits that all people with autism share a similar genetic profile, but some individuals’ symptoms are subtler or milder, delaying recognition. The second theory suggests that autism diagnosed in childhood and autism diagnosed later truly represent different forms of the condition with distinct genetic patterns and clinical implications. The Nature study leans toward the latter, indicating meaningful differences between the two groups.
Dr. Thomas Bourgeron of France’s Pasteur Institute, a co-author, summarized the key finding when speaking with AFP: those diagnosed later in life are genetically more similar to people with attention-deficit/hyperactivity disorder (ADHD) than to early-diagnosed individuals. This overlap with ADHD traits may help explain why late-diagnosed autism sometimes presents differently and may require tailored assessment and support.
Genetics, ADHD links, and mental health
Beyond genetic distinctions, the study reported higher susceptibility to mental health challenges among late-diagnosed individuals, including depression. This aligns with broader clinical observations that autism’s impact varies widely between individuals. Emeritus Professor Uta Frith of University College London, while not involved in the study, noted that recognizing subgroups within autism could lead to more precise diagnoses and personalized care plans. “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?” she told AFP, underscoring the need for nuance in both research and clinical practice.
Implications for diagnosis and care
The findings argue for a shift in how clinicians approach autism across the lifespan. If late-diagnosed autism constitutes a different phenotype with distinct genetic and cognitive profiles, then assessments, interventions, and support services should be customized to the patient’s specific subtype rather than applying a one-size-fits-all model. The authors emphasize that people with autism are “very different from one another,” and care should be tailored to individual needs, including comorbid conditions such as ADHD and mood disorders.
Public discourse and the autism conversation
The study arrives amid ongoing public debates about autism, including controversial commentary from high-profile figures who have linked autism to vaccines or other unfounded theories. The researchers and many clinicians caution against conflating different autism subtypes or attributing a single cause or universal treatment. Correct interpretation of genetic findings is essential to advancing understanding and reducing stigma rather than fueling broad-brush narratives. The scientific community’s goal is to refine diagnostic categories so each person receives the most appropriate care.
Bottom line
While more research is needed to map the full complexity of autism across the lifespan, this study adds important evidence that late-life autism may be a distinct form with unique genetic signals and mental-health considerations. Recognizing subgroups within autism could improve diagnostic accuracy and enable more personalized interventions that better support individuals wherever they are on the spectrum.
