This article was first published on November 20, 2023. It was last reviewed, updated, or edited on November 20, 2023. ADHD is a “Neurodevelopmental Disorder” Attention-deficit/ hyperactivity disorder (ADHD) is included in DSM-5-TR™ in the chapter on Neurodevelopmental Disorders, a group of conditions with onset early in life—during the developmental period (American Psychiatric Association, 2022). Let…