Late diagnosis of autism linked to  higher mental disorder risks: Study

The age at which a child is diagnosed with autism may reflect differences in their biology and development, with later diagnoses associated with an increased risk of mental health disorders, including depression, a new study published in Nature suggests.

Autism, a neurodevelopmental disorder affecting brain regions such as the cerebellum and amygdala, can impair social and emotional skills. Symptoms — such as not responding to one’s name or avoiding eye contact — typically appear in the first year or by age two.

Researchers, including those from the University of Cambridge, UK, found distinct genetic and developmental patterns between children diagnosed early and those diagnosed later, often in late childhood. In early-diagnosed cases, difficulties with social interaction, anxiety, and hyperactivity appear early but remain stable. In contrast, late-diagnosed children show increasing challenges during adolescence.

The study noted that those diagnosed later were more likely to experience mental health conditions such as depression, PTSD, self-harm, and consequences of childhood maltreatment compared to early-diagnosed children.

"The earlier-diagnosed autism factor had a low ... genetic correlation with educational attainment, cognitive aptitude, ADHD and various mental-health and related conditions," the authors wrote.

"The later-diagnosed autism factor showed a ... significantly higher genetic correlations with ADHD and a range of other mental health and related conditions, including depression, PTSD (post-traumatic stress disorder), childhood maltreatment and self-harm," they said.

Data for the study were drawn from research published between 1998 and 2024, including sources such as Google Scholar and PubMed.