Causes

ADD/ADHD is not caused by poor parenting, family problems, poor teachers or schools, too much TV, food allergies, or excess sugar. One early theory was that attention disorders were caused by minor head injuries or damage to the brain. While a number of studies have suggested that refined sugar and food additives made children hyperactive and inattentive, according to the National Institute of Health, diet is a component of ADHD in only about 5% of children with the disease -- primarily very young children or children with food allergies. Although food allergies have recently been associated with a higher risk for behavioral problems, children who respond to allergen-restrictive diets in all likelihood were not suffering from ADHD.

ADHD is a neurobiological disorder. The most recent research shows that the symptoms of ADD/ADHD are caused by a chemical imbalance in the brain.

Studies at NIMH observing the brain at work have shown a link between a personís ability to pay continued attention and the level of activity in the brain. Using a positron emission tomography scanner, researchers measured the level of glucose used by the areas of the brain that inhibit impulses and control attention. In people with ADHD, the brain areas that control attention used less glucose, indicating they were less active. It appears from this research that a lower level of activity in some parts of the brain may cause inattention and other ADHD symptoms. In some studies, brain scans reveal that the right side of the brain is smaller in ADHD children than in non-ADHD children. One recent study reported that adults with ADHD had abnormally low levels of the brain enzyme that produces dopamine, which in turn affects mental and emotional functioning.

In addition, there is a great deal of evidence that ADHD runs in families, which suggests genetic factors. If one person in a family is diagnosed with ADHD there is a 25- 35% probability that any other family member also has ADHD, compared to a 4- 6% probability for someone in the general population.