Attention deficit hyperactivity disorder (ADHD) is a condition that includes symptoms such as inattentiveness, hyperactivity and impulsiveness.  Symptoms of attention deficit hyperactivity disorder include a short attention span, constantly fidgeting and acting without thinking.  Attention deficit hyperactivity disorder can often be treated with medicines and talking therapies.  It's not clear what causes attention deficit hyperactivity disorder, but it tends to run in families.  Sometimes things can go unnoticed because the symptoms may be less obvious.