ADHD is a condition marked by persistent inattention, hyperactivity, and/or impulsivity. ADHD begins in childhood and often lasts into adulthood. About 30% to 50% of children with ADHD continue to have symptoms as adults.
Symptoms of ADHD can differ from person to person, but involve some combination of hyperactivity, impulsivity, and inattention. When activity levels are normal or low, it is usually called attention deficit disorder (ADD). The symptoms of hyperactivity and possibly impulsiveness appear to diminish with age.
Children with ADHD have trouble functioning at home and in school and often have trouble with friends. If left untreated, ADHD may interfere with school and jobs, as well as social and emotional development.
ADHD is more common in boys, whose impulsivity and hyperactivity may be evident. Inattentiveness is a hallmark of ADHD in girls, but if they aren't disruptive in the classroom, they may not get diagnosed.
ADHD tends to run in families. When one person is diagnosed with ADHD, there is a 25%-35% chance that another family member will also have the condition, compared to 4%-6% of the general public.
No one knows for sure whether ADHD is more common today, but it is very clear that the number of children getting treatment for ADHD has risen in recent decades. Some of this increase in diagnosis and treatment is due to greater awareness. Some experts feel that ADHD is overdiagnosed, while others feel it is underdiagnosed.