ADHD is a neurobiological disorder that affects people of every age, race, socioeconomic background, and culture. ADHD has long been viewed as a condition that primarily affects boys and men — and it does affect about twice as many men as women. However, that still means there are millions of women with the condition. Until the 1970s, researchers believed that ADHD was a childhood disease that children outgrew by puberty. Today, studies show that up to 50 percent of children with ADHD still have symptoms as adults.