Attention Deficit Hyperactivity Disorder (ADHD/ADD) is not a behavior disorder, nor is it a lack of will-power. ADHD is a neuro-development, or brain, disorder that interferes with functions essential to self-management.
All children display moments where they simply don't pay attention, talk excessively, are over-excited and may even act impulsively, but for a child with ADHD these behaviors persist and affect day-to-day functions. A child with ADHD shows a greater intensity of sustained immaturity in comparison to his/her peer group.
There are two presentations of the diagnosis:
Attention Deficit Disorder (ADD): predominantly inattentive, lacking the hyperactive/impulsive issues
Attention Deficit Hyperactivity Disorder (ADHD): predominantly hyperactive and impulsive symptoms; or a combination of both inattentive (ADD) and hyperactive/impulsive (ADHD) symptoms
For simplicity, ADD is often rolled up under the term ADHD; however, please note that is important to get an accurate diagnosis.
Obtaining an accurate diagnosis can be difficult as many other disorders and conditions commonly co-exist with ADHD, and frequently present overlapping symptoms. Leading expert Thomas E. Brown noted that 67% of kids with ADHD have at least one co-occurring learning or mental health issue including the possibility of a learning disability, conduct disorder, anxiety or depression.