There are many theories about what causes ADD or attention deficit disorder.
Many studies have been conducted to try and discover the cause of the disorder that affects about 2 million children in the U.
S.
alone.
While some great discoveries have been made that have shed light on the disorder, experts still don't know exactly what causes it.
The factors that seem to have the biggest impact in the development of ADD are genetics and neurological function.
Studies have shown that the brain activity of many children with the disorder is underdeveloped for their age in the areas that control attention and impulsiveness which are two of the main symptoms of ADD.
Studies have also shown that parents who have ADD or had it as a child are more likely to have children with the disorder.
Children with a sibling who has ADD are three times more likely to have the disorder as well.
These findings support the theory that ADD is caused in part by hereditary neurological problems.
Some people believe that environmental factors such as diet, tobacco and alcohol use in pregnant women, and parenting have a lot to do with ADD.
Studies have yet to find a definitive link between any of these factors and the disorder, although some food additives such as red dye seem to make ADD symptoms worse.
Some foods such as Omega 3 and Omega 6 acids seem to make symptoms better as well.
Sugar, which was once though to be the main cause of hyperactivity in children, has recently been proven not to have an impact on ADD symptoms at all.
There is no test for ADD because it is a clinical diagnosis made by examining symptoms and behaviors that are present in a child and ruling out any other disease or disorder that can cause the same symptoms.
Most experts agree that the disorder is probably caused by a combination of factors, including genetics and neurological differences in the brain although some evidence has pointed to environmental factors such as diet that can also contribute to ADD symptoms.