ADHD affects an estimated 8% to 10% of all school-age children worldwide. It is not the result of laziness, low intelligence, poor parenting, or a child being "bad". And it's not a purely "American" disorder- it's found in all cultures.
Boys are about three times more likely than girls to be diagnosed with ADHD, though it's not yet understood why.
ADHD does tend to run in families. If a person has ADHD, it can be expected that over 25% of their first-degree relatives (that being mother, father, siblings, and/or children) will also show symptoms of ADHD. This genetic link is even higher among identical twins - if one identical twin has symptoms of ADHD, there is an 82% chance that the other one will, too.
Although ADHD symptoms tend to diminish with time, research suggests that up to 60% of children with ADHD will continue to have symptoms into adulthood.
