Attention-Deficit Hyperactivity Disorder, Ritalin, and the Brain

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Biology 202
2002 First Paper
On Serendip

Attention-Deficit Hyperactivity Disorder, Ritalin, and the Brain

Sujatha Sebastian

Attention-Deficit Hyperactivity Disorder, more commonly referred to as simply ADHD, is the most commonly diagnosed disorder among American children today. According to the National Institute on Mental Health an estimated 3 to 5 percent of school age children are affected by this disorder. (1) There are more diagnosed cases of ADHD of in the United States than there are anywhere in the world. The main symptoms of ADHD include "developmentally inappropriate levels of attention, concentration, activity, distractibility, and impulsivity." (1) While the number of people diagnosed with ADHD increases dramatically every year, there is still much about the disorder that is not understood. While scientists have deduced that ADHD originates in the brain, they still have many questions about the nature of it. The classification of Attention-Deficit Hyperactivity Disorder has become quite a controversial topic in American society today. There are some who believe that by recognizing the symptoms associated with the disorder as ADHD; science is simply putting a band-aid on a problem that could be otherwise corrected with behavior modification.

The lack of a complete understanding of ADHD has led scientists to question how to go about treating ADHD. While at the moment the disorder cannot be cured, they are methods that scientists have come up with to address the symptoms displayed by ADHD. These approaches range all the way from psychotherapy, and cognitive-behavioral therapy, to the prescription of pyschostimulant medications. (3) The most popular of these medications include amphetamines, such as Aderall, and methylphenidates such as Ritalin. (1) The use of such drugs has caused controversy among scientists and general American society alike. If we do not understand the exact nature of Attention-Deficit Hyperactivity Disorder is it appropriate to use drugs as methylphenidates to deal with it? While studies conducted on the short-term use of these drugs have indicated strongly favorable results in reducing the symptoms of ADHD, at the present there have not been any conclusive studies to show the long-term effects of methylphenidate.

To look at the other side of the debate on ADHD one must also consider the argument that while scientists at the moment do not completely understand the nature of ADHD, they are obligated to learn more. If the use of Ritalin has shown obviously beneficial effects is it not logical to use it? The debate surrounding the use of psychostimulants drugs, and more specifically Ritalin, has mainly to do with the lack of understanding concerning ADHD than it does with the drugs themselves. Scientists believe that one first one has to recognize ADHD as a disorder before one can proceed to evaluate its treatments. Ultimately the battle over Ritalin and ADHD demonstrates the lack of understanding we as humans have of the brain and how it functions.

Attention-Deficit Hyperactivity Disorder most popularly associated with an inability to concentrate has been identified by the American Psychiatric Association as displaying nine possible symptoms. To be diagnosed with ADHD a person must display at least six of the nine symptoms. These symptoms include:
-Making careless mistakes in schoolwork
-Difficulty sustaining attention to tasks
-Not listening to what is being said
-Losing and misplacing belongings
-Fidgeting and squirming when seated
-Talking excessively
-Interrupting or intruding on others
-Difficulty in playing quietly (2)

There is still much that is unknown as to what causes ADHD. While it has been determined that the disorder is a result of a behavior in the brain, there are still specific questions that are unanswered. Research has led scientists to believe that the prefrontal cortex, a part of the cerebellum, and a group of nerve cells, referred to as the basil ganglia are involved in ADHD. (3) Studies of children with ADHD have showed that their prefrontal cortex and their basil ganglia were smaller when compared to children who did not have the disorder. The prefrontal cortex in the brain is one of the areas responsible for editing a person's behavior. The basil ganglia coordinate neurological input activity in the brain. (3) While the prefrontal cortex and the basil ganglia have been identified as playing a role in ADHD scientists do not yet understand what causes these areas to shrink. Among children studied the shrinkage in their brain has been associated with a mutation of genes. This has provided scientists with the clue that ADHD is possibly caused by malfunction of more than one gene, making it a polygenic disorder. (3)

The question scientists are now asking is which genes specifically are defective? A great amount of research has been focused on the role that dopamine, a neurotransmitter in the brain, plays. (2) Dopamine is released by neurons in specific parts of the brain to control the activity of other neurons. There are dopamine receptors that sit on the outside of specific neurons. The dopamine then enters these neurons through the specific receptor. There are also dopamine transporters that sit on the outside of other neurons. These transporters gather dopamine that has been released in the brain, but not used, together again. In persons with ADHD it is these transporters that are either unreceptive, or overly receptive. The result is an imbalance in the level of dopamine present in the brain. (3)

The incorrect transportation of dopamine causes a person with ADHD to have limited control over their executive functions. These executive functions include four operations: the operation of working memory, the internalization of self-directed speech, the controlling of emotions, and the reconstitution of behavior. (3) Scientists' understanding of the role that dopamine plays in ADHD has led them to try and control the levels of dopamine released in the brain. This has been done by the use of psychostimulants. The most popular of these psychostimulants is methylphenidate, better known as Ritalin. Ritalin affects ADHD by preventing dopamine transmitters from collecting released dopamine. In one study the use of psychostimulants seemed to help improve the behavior of 70 to 90 percent of children who took it. (3)

The sharp increase in the number of diagnosed cases of ADHD has led to a dramatic increase in the number of people using pyscholstimulants. The prescription of methylphenidate has increased so much so that it has sparked a debate among scientists and mainstream American society alike. Many ask what the effects of the dependency on pyschostimulants are. What does it mean to have such a large number of people on such powerful drugs? While the use of any powerful drug can cause debate, the one surrounding the use of Ritalin is so intense in part because of the nature of the nature of the drug. Methylphenidate belongs to the same family of drugs that cocaine does. (6) While several studies have shown that Ritalin when administered in small dosages can have an overtly positive effect on ADHD, many are worried that a dependency on Ritalin will lead to greater problems. (4)

Ritalin functions by creating a balance in the level of dopamine transmitted in the brain. It is in fact a pyschostimulant, but it works by preventing the stimulation of dopamine transporters. Ritalin is prescribed in the form of a tablet. It is given in 5, 10, or 20 mg dosages. (5) Once taken Ritalin produces a calming effect. It aids the brain in performing its executive functions. The side effects associated with Ritalin can include lack of hunger, loss of ability to sleep, and headaches. (5)

One of the biggest things that scientists have been trying to learn about is the long-term effect of Ritalin on the brain. At the moment they are unsure. A research project conducted at the University of Buffalo showed that methylphenidate has the potential to cause long lasting changes in brain cell structure. In the study 20 mg per kg were prescribed to mice. (The prescribed dosage for a human would be .3 to .7 mg per kg). The changes produced in the brains of the mice resembled changes in the brain caused by cocaine usage. (8) The study concluded that Ritalin as it is prescribed among humans not only appears to be safe, but beneficial.

There is great uncertainty in the medical world surrounding Attention-Deficit Hyperactivity Disorder. While scientists now understand part of the process of how ADHD develops its, they are still unsure about a lot. The biggest debate concerning ADHD is how to treat it. Science and society alike have contrasting views on how ADHD can be best dealt with. One's opinion on how to treat ADHD goes in accordance with one's interpretation of the disorder. Scientists who see ADHD as the result of a chemical imbalance look to drugs for a solution. Others who see ADHD as simply a behavioral problem look to behavior modification techniques for help. Ultimately the debate surrounding ADHD demonstrates how the little we as humans understand about the brain and its functions. While this is only natural, for science is simply a system of trial and error, . . . the question then becomes how do we proceed to become "less wrong" about Attention-Deficit Hyperactivity Disorder?


1)Attention Deficit Hyperactivity Disorder (ADHD)-Questions and Answers, National Institutes of Health

2) Attention Deficit Disorder (ADD), Attention Deficit Hyperactivity Disorder (ADHD, AD/HD) A Developmental Approach, National Information Center for Children and Youth with Disabilities (NICHCY)

3)Attention-Deficit Hyperactivity Disorder, Scientific American Online

4) Methylphenidate (Ritalin), National Institute on Drug Abuse

5) Ritalin: Prescribing Information, Novartis Pharmaceuticals Corporation

6) The Hazards of Treating "Attention-Deficit/Hyperactivity Disorder" with Methylphenidate (Ritalin), The Journal of College Student Psychotherapy

7) Information About ADD, Scientific American Online

8) University At Buffalo Research on Long-Lasting Effects of Ritalin in Brain-Cell Function, Science Daily

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