ADHD is "Real"
< Aug. 08, 2007 > -- Attention-deficit/hyperactivity disorder (ADHD) is an identifiable disease linked to changes in production of the brain chemical dopamine, two new reports suggest. Dopamine is a chemical substance, called a neurotransmitter, found in the brain that regulates movement, balance, and walking.
ADHD is the most prevalent psychiatric disorder among children. "Despite decades of research, the specific neurobiological mechanisms underlying this disorder still remain unclear," the study authors write. "Genetic, clinical, and imaging studies point to a disruption of the brain dopamine system, which is corroborated by the clinical effectiveness of stimulant drugs (methylphenidate hydrochloride and amphetamine), which increase extracellular dopamine in the brain."
In the first report, researchers found that a version of the dopamine receptor gene may help cause ADHD, but may also improve the disease's outcome.
"If you have a certain variant of this gene, you have a greatly increased risk of having ADHD," says head researcher, Dr. Philip Shaw, from the Child Psychiatry Branch at the US National Institute of Mental Health.
Dr. Shaw also states, "The kids who had the risk gene tended to get better. They also tended to be a little bit more intelligent."
Not all children with the gene variant had ADHD. But it was present in one-quarter to one-fifth of children with ADHD. This is higher than the general population, of which one-fifth to one-sixth has the genetic variant.
Dr. Shaw's team discovered the genetic variability by comparing 105 children with ADHD to 103 children who did not have the disorder. The children, who averaged 10 years of age, had magnetic resonance imaging (MRI) brain scans and DNA testing.
Also, 67 of the children with ADHD were evaluated six years later.
The gene variant was found in the dopamine D4 receptor gene (DRD4), associated with ADHD. This form of the gene is also linked with thinner tissues in certain areas of the brain that control attention.
In the children followed for six years, those who had the gene variant present had better outcomes and regained healthy tissue thickness in the affected brain region. This finding may help explain how ADHD tends to improve with age, notes the research team.
Dr. Shaw states, "This is a very important study as it adds increasing evidence that ADHD is a heritable [can be inherited] disease with genetically determined neurobiological underpinnings and adds further evidence that this is a valid mental disorder, often requiring neurobiological interventions [such as] pharmacological treatment."
In the second study, led by Dr. Nora D. Volkow, of the US National Institute on Drug Abuse, researchers discovered that, in contrast to common belief, ADHD is associated with lowered dopamine production, instead of higher production.
The study found that adults with ADHD who received the drug methylphenidate (Ritalin) had a blunted response to the medication.
Dr. Volkow noted that "Individuals with ADHD have a decreased function of the brain dopamine system. ADHD, clearly, is associated with a biochemical dysfunction."
This knowledge is important because it defends against the myth that ADHD is a disorder created in order "to sell medication," Dr. Volkow reports. This research supports the premise that stimulant medications, such as Ritalin, are beneficial because they increase the dopamine function in the brain, researchers say.
Both reports were published in a recent issue of the Archives of General Psychiatry.
Dr. Volkow also notes that drugs such as nicotine, cocaine, and methamphetamine also improve dopamine function.
"This may be the reason why individuals that have ADHD are at a much greater risk of abusing substances than the general population, because drugs of abuse increase dopamine brain function, and they will 'feel better,'" Dr. Volkow said.
Always consult your physician for more information.
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ADHD, also called attention-deficit disorder, is a behavior disorder, usually first diagnosed in childhood, that is characterized by inattention, impulsivity, and, in some cases, hyperactivity. These symptoms usually occur together. However, one may occur without the other(s).
The symptoms of hyperactivity, when present, are almost always apparent by the age of 7 and may be apparent in very young preschoolers. Inattention or attention-deficit may not be evident until a child faces the expectations of elementary school.
How is attention-deficit/hyperactivity disorder diagnosed?
ADHD is the most commonly diagnosed behavior disorder of childhood. A pediatrician, child psychiatrist, or a qualified mental health professional usually identifies ADHD in children. A detailed history of the child's behavior from parents and teachers, observations of the child's behavior, and psychoeducational testing contribute to making the diagnosis of ADHD.
Further, because ADHD is a group of symptoms, often diagnosis depends on evaluating results from several different types of evaluations, including physical, neurological, and psychological. Certain tests may be used to rule out other conditions, and some may be used to test intelligence and certain skill sets.
Treatment for attention-deficit/hyperactivity disorder:
Major components of treatment for children with ADHD include parental support and education in behavioral training, appropriate school placement, and medication (psychostimulants). Treatment with a psychostimulant is highly effective in most children with ADHD.
Treatment may include:
Psychostimulant medications, used for their ability to balance chemicals in the brain that prohibit the child from maintaining attention and controlling impulses, may be used to reduce the major characteristics of ADHD, which include inattention,impulsivity, and/or hyperactivity.
There are four different psychostimulant medications that are commonly used to treat ADHD, including the following :
- methylphenidate (Ritalin)
- dextroamphetamine (Dexedrine)
- a mixture of amphetamine salts (Adderall)
- atomoxetine (Strattera)
Most side effects of stimulant use are mild, decrease with regular use, and respond to dose changes.
Antidepressant medications may also be administered for children and adolescents with ADHD to help improve attention while decreasing aggression, anxiety, and/or depression.
Parenting children with ADHD may be difficult and can present challenges that create stress within the family. Psychosocial treatments may be useful in coping with ADHD.
Classes in behavior management skills for parents can help reduce stress for all family members. Training in behavior management skills for parents usually occurs in a group setting which encourages parent-to-parent support.
Behavior management skills may include use of "time out"; point systems; or contingent attention (responding to child with positive attention when desired behaviors occur; withholding attention when undesired behaviors occur).
Behavior management techniques tend to improve targeted behaviors (such as completing school work or keeping the child's hands to himself/herself), but are not usually helpful in reducing inattention, hyperactivity, or impulsivity.
Always consult your physician for more information.
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