The ADHD Brain

What is ADHD?
ADHD stands for Attention Deficit Hyperactivity Disorder. Generally, ADD and ADHD are used interchangeably, although technically do not refer to the same disorder. ADD is an inattentive disorder where a patient has difficulty maintaining attention to one stimulus and is easily distracted by other stimuli. ADHD is a similar attention disorder that also involves a hyperactive component.  Together they are often known as ADD/HD.

ADHD is characterized by
1) Impulsivity
2) Inattention
3) Hyperactivity
These things can cause behavioral problems, both in school and at home, which can affect a child's relationships, motivation to learn, and overall satisfaction with life.

ADHD is often accompanied by disorganization, aggressive behavior, low self-esteem, sensation seeking, frequent daydreaming, coordination problems, poor memory, and behavioral "inconsistency." All of these things further contribute to a child's difficulties and interfere with daily functioning.

Biological Basis for ADHD

Genetic Causes
Studies of families of children with ADHD have shown that this disorder seems to run in families. When one twin is diagnosed with ADHD there is a much higher likelihood that the other twin will be diagnosed as well, as opposed to the other siblings in the family. Twins share many more of their genes than regular siblings. Similarly, studies of adopted children have found that there is a greater connection between whether the child's biological parents have been diagnosed with ADHD than if the adopted parents have been diagnosed.

It seems from these studies that there is a strong genetic component to ADHD, as opposed to a child being affected by the organization in the environment around them. However, researchers have yet to isolate a single gene that causes ADHD. Rather, it is theorized that there are several factors that can contribute to ADHD. This explains why there seem to be so many different types of ADHD and why no one treatment works for every child, although there are many successful therapies and medications that can help a child manage their condition.

Neuropsychological Causes
Brain scans comparing brain function in children with ADHD and a control group have shown lower blood flow in the frontal lobes, which are involved in attention and impulse control. The frontal lobes are also known as the "Executive Brain," since they are involved in higher order cognitive tasks such as organization and attention. They can be compared to a band conductor who is not himself playing music, but without whom there would be no concert.

Neurochemical Causes
Dopamine is a hormone produced by the brain that is involved in regulating memory, attention, problem solving, and motivation - all things that are compromised in children diagnosed with ADHD. Dopamine production has been shown to be lower in children with ADHD.  Ritalin and other stimulants can increase the level of dopamine in the brain and is used help kids with ADHD focus better on tasks.