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ADHD research exploding in recent months

2011-12-13 13:30

In recent months, researchers have published a large amount of material regarding attention deficit hyperactivity disorder (ADHD). The condition is one of the most common childhood disorders and can continue through adolescence and adulthood. It is characterized by the inability to focus or pay attention, hyperactivity and impulsive behavior. The behavior problems are so frequent that they interfere with the child's ability to adequately function on a daily basis without treatment. Symptoms include difficulty staying focused and paying attention, difficulty controlling behavior, and hyperactivity. Amphetamine (Adderall), methylphenidate (Ritalin) and other central nervous system stimulants are given to children who suffer from ADHD. Interestingly, these drugs do not have the stimulant effect observed in adults when given to children before they reach puberty. In the U.S., approximately 2.7 million children are prescribed ADHD medication, primarily to reduce impulsive behavior as well as to improve focus and attention span. In addition, more than 1.5 million adults also take the medications. Over the past decade, the use of ADHD drugs in adults has outpaced that in children.

On October 16, the American Academy of Pediatrics (AAP) released new guidelines. They provide instructions for pediatricians on diagnosing and managing ADHD in children 4 to 18. According to the new guidelines, behavioral management techniques should be the first treatment approach for preschool-age children. However, they also suggest that physicians consider prescribing Ritalin in preschool-age children with moderate to severe symptoms when behavioral intervention does not provide significant improvement. This recommendation is potentially controversial because methylphenidate is not approved by the Food and Drug Administration (FD) for use within that age group. Many ADHD medications are approved for children age six and older. The prior set of AAP guidelines, issued about a decade ago, gave recommendations for children six to 12. In addition to preschool-age children, the new recommendations also address teenagers who might not have been diagnosed at a younger age.

According to the guidelines, to correctly diagnose a child with ADHD, the overactive, impulsive behavior needs to be seen consistently for four to six months in both the home and another environment such as school. The guidelines recommend that parents undergo training to help modify behaviors associated with ADHD. Such techniques involve setting up a reward-and-punishment system and stress the consistent application of the modification techniques. Furthermore, medication should be considered for preschool-age children only if they exhibit symptoms of ADHD for at least nine months and only after behavior management techniques have been tried. For children age six through 12, the guidelines suggest a combination of behavior training and medication. Doctors stress that controlling the symptoms of ADHD in school-age children is important to boosting their chances of success in school.

They are categorized as stimulants and appear to boost and balance brain chemicals called neurotransmitters, which helps address symptoms of inattention and hyperactivity. ADHD medications have some side effects, including decreased appetite, weight loss and, sometimes, trouble sleeping. Another concern is that the medications could damage the heart. These concerns are based on the fact that they cause a modest increase in heart rate and blood pressure.

In 2005, fears regarding a potential risk of heart damage from ADHD medications arose because of reports of about a dozen deaths from sudden cardiac arrest among young users of Adderall. As a result, the Canadian government temporarily banned the sale of Adderall; however, the suspension was later determined that the patients who had died had heart defects or other underlying heart disease.

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In 2006 in the U.S., the Food and Drug Administration (FDA) held advisory panels to discuss the cardiac risk of ADHD drugs. Subsequently, the FDA mandated an update to product labeling to mention cardiac risk. In 2008, the American Heart Association (AHA) recommended that children being considered for ADHD medications undergo a thorough heart exam, possibly including an electrocardiogram, before taking them.

A large new study, which was published online on December 12 it the Journal of the American Medical Association (JAMA), has eased the concerns of heart damage. Researchers at Kaiser Permanente—Northern California (Oakland, CA) analyzed the health records of nearly 500,000 adults; their study shortly after a separate study, which reached a similar conclusion about the drugs’ effect in 1.2 million children and young adults. Both studies found no evidence of heart damage from the medications; however, they both noted that the ADHD drugs have other side-effects, such as anxiety and a slowing of growth in children. "We don't see any evidence they're increasing risk," noted Laura A. Habel, a Kaiser Permanente research scientist.

Both the study, published online December 12 in JAMA and the previous one, published last month in the New England Journal of Medicine, were funded by the FDA and other U.S. agencies in order to clarify the risk associated with the ADHD drugs following the 2006 advisory panel hearings. The JAMA study compared about 150,000 adult users of ADHD medications between the ages of 25 and 64 years to approximately 300,000 nonusers. The Kaiser researchers reviewed medical records from four health insurance plans to look at the number of serious cardiovascular events such as sudden cardiac death, heart attack, and stroke among both groups. The study found that 1,357 heart attacks, 296 cases of sudden cardiac death, and 575 cases of stroke occurred among all the patients. The rate was similar among users and nonusers of ADHD drugs; this suggested that the medications did not increase risk of developing serious cardiovascular problems.

The November study, by the same research team, reached a similar conclusion among patients aged two to 24. The patients evaluated in the studies were not randomized and the average duration of treatment was relatively short; as a result, the researchers cautioned that an increased risk associated with the drugs. "Even though we can't rule out increased risk," said William Cooper, a pediatrician at Vanderbilt University, Nashville, Tenn., and lead author of November study, "the absolute magnitude would be low because the [serious] events are so rare."

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