ADHD stands for Attention Deficit Hyperactivity Disorder.   Here is an excerpt from a FAQ concerning ADD and ADHD.

Q:   What is an Attention Deficit Disorder?
A:   Attention Deficit Disorder (ADD) is a syndrome which is usually characterized by serious and persistent difficulties resulting in:
      a) poor attention span
      b) weak impulse control
      c) hyperactivity

ADD also has a subtype which includes hyperactivity (ADHD).   It is a treatable (NOTE: not curable) complex disorder which affects approximately 3 to 6 percent of the population (70% in relatives of ADD children).   Inattentiveness, impulsivity, and often times hyperactivity are common characteristics of the disorder.   Boys with ADD tend to outnumber girls by 3 to 1, although ADD in girls is under-identified.   The term ADD is usually referring to ADHD.   ADD without hyperactivity is also known as ADD/WO (With Out) or Undifferentiated ADD.

This gives you a basic definition of ADHD.   I set this page up with the hope of making information on this subject more available.   My son, who is now 7, was 3 when he was diagnosed as ADHD.   This sent me on a search for information.   I found many sources on the internet.   This page is an attempt to gather the sites that I found useful.   If you know of any that I have missed, please let me know.   On the bottom of this page are my email address, and icq UIN.