First Steps: Understanding the Adult ADHD Assessment Process Attention-deficit/hyperactivity disorder (ADHD) is a chronic neurodevelopmental condition characterized by inattention, hyperactivity, and impulsivity. Although ADHD is commonly diagnosed in childhood, it can also persist into adulthood. In fact, recent studies suggest that up to 4.4% of adults in the United States have ADHD. If you suspect you have ADHD, it is essential to undergo an adult...