ADHD Brains Develop More Slowly, But Generally Catch Up Later

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Main Category: ADHD
Also Included In: Neurology / Neuroscience;  Psychology / Psychiatry;  Mental Health
Article Date: 13 Nov 2007 - 13:00 PDT

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Children with Attention Deficit Hyperactivity Disorder (ADHD) have slower developing brains, when compared to children without ADHD, however, in most cases they still follow a normal pattern of development, according to an article in Proceedings of the National Academy of Sciences (PNAS).

The scientists found that the outer mantle of the brain - the cortex - develops with an average delay of three years among ADHD children. They studied 450 children, 225 had ADHD, while the other 225 did not. The cortex plays an important role in our planning and attention, the researchers explain.

The scientists, from the National Institute of Mental Health (NIMH), say their study may eventually lead to novel treatments for ADHD.

The researchers wanted to find out when the brain reaches peak thickness - a sign that it has matured. Half of the children with ADHD reached peak thickness when they were, on average 10.5 years old, compared to 7.5 years among children without ADHD.

However, even though many ADHD children's brains were developing three years behind the other children, their brains still followed a normal pattern of development.

Lead researchers, Dr. Philip Shaw, said "Finding a normal pattern of cortex maturation, albeit delayed, in children with ADHD should be reassuring to families and could help to explain why many youth eventually seem to grow out of the disorder."

The next step, the authors explain, will be to try to find out why this delay occurs, and look at ways of speeding it up.

Some experts say the idea of "catching up" is somewhat misleading. While an ADHD person is catching up, those without ADHD continue to develop further.

"Brain Matures a Few Years Late in ADHD, But Follows Normal Pattern"
National Institute of Mental Health
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What is ADHD?

ADHD (Attention Deficit Hyperactivity Disorder) is one of the most common neurobehavioral disorders of childhood and can persist through adolescence and into adulthood. Currently the causes are unknown.

A person with ADHD has a chronic level of inattention, impulsive hyperactivity, or both such that daily functioning is compromised.

The symptoms of the disorder must be present at levels that are higher than expected for a person's developmental stage and must interfere with the person's ability to function in different settings (e.g., in school and at home).

A person with ADHD may struggle in important areas of life, such as peer and family relationships, and school or work performance.

The American Psychiatric Association's Diagnostic and Statistical Manual-IV, Text Revision (DSM-IV-TR) estimates that 3%-7% of children suffer from ADHD. Some studies have estimated higher rates in community samples. ADHD is diagnosed approximately three times more often in boys than in girls.

Three types of ADHD have been established according to which symptoms are strongest in the individual. These types are described below:

1. PREDOMINANTLY INATTENTIVE TYPE: It is hard for the individual to organize or finish a task, to pay attention to details, or to follow instructions or conversations. The person is easily distracted or forgets details of daily routines.

2. PREDOMINANTLY HYPERACTIVE-IMPULSIVE TYPE: The person fidgets and talks a lot. It is hard to sit still for long (e.g., for a meal or while doing homework). Smaller children may run, jump or climb constantly. The individual feels restless and has trouble with impulsivity. Someone who is impulsive may interrupt others a lot, grab things from people, or speak at inappropriate times. It is hard for the person to wait their turn or listen to directions. A person with impulsiveness may have more accidents and injuries than others.

3. COMBINED TYPE: Symptoms of the above two types are equally predominant in the person.

As many as half of those with ADHD also have other mental disorders. These comorbidities of ADHD (other disorders that occur along with ADHD) can make it harder to diagnose and treat ADHD. They may also present further challenges to the individual with ADHD.

Used by mental health professionals, the DSM-IV-TR provides criteria for diagnosing ADHD. This diagnostic standard helps ensure that people are appropriately diagnosed and treated for ADHD. Using the same standard across communities will help determine the public health impact of ADHD.

Treating ADHD can be done through medical or behavioral therapies, or a combination of the two.

Criteria for the three primary subtypes are:

AD/HD - INATTENTIVE TYPE
-- Fails to give close attention to details or makes careless mistakes.
-- Has difficulty sustaining attention.
-- Does not appear to listen.
-- Struggles to follow through on instructions.
-- Has difficulty with organization.
-- Avoids or dislikes tasks requiring sustained mental effort.
-- Loses things.
-- Is easily distracted.
-- Is forgetful in daily activities.

AD/HD - HYPERACTIVE TYPE
-- Fidgets with hands or feet or squirms in chair.
-- Has difficulty remaining seated.
-- Runs about or climbs excessively.
-- Difficulty engaging in activities quietly.
-- Acts as if driven by a motor.
-- Talks excessively.
-- Blurts out answers before questions have been completed.
-- Difficulty waiting or taking turns.
-- Interrupts or intrudes upon others.

AD/HD - COMBINED TYPE
-- Individual meets both sets of inattention and hyperactive/impulsive criteria.

Written by - Christian Nordqvist
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