New research identifies differing trends in attention-deficit/hyperactivity disorder (ADHD) diagnoses among adolescents and adults, including an increase among adults from 2020 to 2023. The study found a significant downward trends in ADHD incidence among adults from 2016 to 2020 and adolescents from 2016 to 2018. The ADHD incidence rate remained stable for adolescents in subsequent years.