Attention Deficit Hyperactivity Disorder

Experts suggest that attention deficit hyperactivity disorder (ADHD) affects an estimated 5 to 8 percent of school-aged children and one to seven percent of adults. ADHD interferes with your ability to regulate activity (hyperactivity), control some behaviors (impulsivity) and focus on tasks (inattention). When the hyperactivity is not present, the condition is sometimes called Attention Deficit Disorder (ADD), although the more current term is ADHD-Inattentive type. As many as two-thirds of children with ADHD will continue to face major challenges caused by the disorder as adults, according to the Attention Deficit Disorder Association (ADDA).

By current estimates, about three times more boys than girls are affected by ADHD, but that gap appears to close across development, with the ratio evening out in adulthood.

Overall, women and girls may have fewer of the typical symptoms associated with ADHD in boys, but once a diagnosis is made, the symptoms are fairly similar. Still, sex differences exist. For example, girls with ADHD may be more likely to be shy rather than hyperactive. They tend to be less defiant and more compliant than boys and men with the condition. Like boys and men with ADHD, however, women with the condition may also have difficulty completing tasks and remaining organized. Instead of being tested for ADHD, they're often dismissed as flighty or spacey.

Thus, because girls are less likely to disrupt class—the kind of behavior that often brings boys with the condition to medical professionals' attention—girls are less likely to get diagnosed with ADHD. Consequently, many girls and women do not get the help they need. Often, girls' self-esteem suffers as they encounter academic problems in school. They may have difficulty with interpersonal relationships as well as social challenges. These secondary difficulties may result in depression, anxiety disorders, problems sleeping and substance abuse.

Once diagnosed, however, many women recall painful or difficult childhood experiences in school that were likely caused by ADHD but attributed at the time to other causes, such as laziness or lack of ability. This can lead to significant emotional or psychological problems.

Causes of ADHDAlthough no one knows for sure what causes ADHD, the condition does run in families, suggesting a strong genetic component. In fact, ADHD is among the most recognized genetic-based disorders in psychiatry. Overall, if a parent has the disorder, there is up to a 40 percent chance that a child will have it. Studies show that if a child has ADHD, there is about a 25 percent chance that one of his or her close relatives will also have the condition. For identical twins, there is a strong chance the other twin has it. This "family resemblance" appears due more to genetic than social factors. Many researchers around the world are now investigating various genes that may contribute to the development of ADHD in families.

A smaller percentage of cases of ADHD are due to environmental causes, including prenatal use of alcohol, tobacco and cocaine, and exposure to lead, which can alter brain development in the fetus. Low birthweight can also lead to ADHD symptoms. Additionally, some postnatal problems, such as chronic low levels of lead or severe head trauma, can result in ADHD.

For years, ADHD was thought to be a disruptive behavior disorder that most experts intuitively believed involved some brain abnormality. With the development of more sophisticated brain scanning techniques, it is now known that people with ADHD do have anatomical differences in their brains, as well as differences in the biochemical balance that controls everything from mood to impulses.

For instance, imaging studies like MRIs show that some areas of the brain in children with ADHD are smaller, or have structural abnormalities, compared to those without the condition.

Another biological component of ADHD has to do with levels of two key neurotransmitters in the brain: norepinephrine and its precursor, dopamine. Both are major neurochemicals responsible for transmission of nerve impulses throughout the brain, and both are thought to be essential in regulating impulse control, organization and attention.

Those with ADHD generally may have increased levels of a transporter protein that reduces the amount of dopamine transmitted between neurons, leading to a dopamine (and thus norepinephrine) deficiency.

Medications like methylphenidate HCL (Ritalin and Concerta) and other stimulants work directly on this mechanism, making more dopamine available for transmission by blocking those proteins, while the newest and first non-stimulant ADHD drug, atomoxetine (Strattera), works on the norepinephrine pathway.

ADHD is not caused by many environmental triggers commonly believed to be associated with the disorder, such as:

too much TV

food allergies

eating too much sugar

poor home life

poor teaching and/or schools

permissive parenting

Still, it is essential to realize that the home environment and the school setting are extremely important in managing ADHD.