Attention deficit hyperactivity disorder (ADHD) may be well known, but there is still a great deal that scientists don't know about it.

Though the past decade has seen increases in prescription drugs used among adults, the use of doctor-prescribed medications among children has actually declined - with some exceptions.

While attention deficit-hyperactivity disorder (ADHD) is most commonly associated with children, adults suffer from it too. New research shows certain medications improve adult ADHD symptoms.