Rising ADHD and Autism Diagnoses May Reflect Broader Diagnostic Criteria

A Danish population-based cohort study found that individuals diagnosed with attention-deficit/hyperactivity disorder (ADHD) or autism spectrum disorder (ASD) in more recent years carried lower average genetic risk scores for these conditions and related psychiatric traits than those diagnosed earlier, suggesting that the rising prevalence of ADHD and ASD is more likely explained by broader diagnostic criteria and increased identification rather than a true increase in underlying genetic risk. Using data from over 17,000 individuals with ASD and 20,000 with ADHD diagnosed between 1994 and 2016, researchers examined polygenic scores for multiple psychiatric and cognitive-behavioral traits. They found that more recent ADHD diagnoses were associated with lower genetic liability for ADHD, ASD, bipolar disorder, and schizophrenia, while more recent ASD diagnoses were associated with lower genetic risk for ASD, bipolar disorder, schizophrenia, and related traits. Comparisons with simulated scenarios indicated that expanding diagnostic boundaries and identifying individuals with milder genetic susceptibility best explained the observed trends. These findings suggest that changes in clinical practice and diagnostic recognition, rather than emerging genetic risk factors, have played a major role in the increasing rates of ADHD and ASD diagnoses over recent decades. Source: https://jamanetwork.com/