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Statement for the Record on Methylphenidate (Ritalin) for Children with ADHD by
Steven E. Hyman, M.D. Director
National Institute of Mental Health
National Institutes of Health
U.S. Department of Health and Human Services

Before the House Education and the Workforce Subcommittee on Early Childhood, Youth, and Families
May 16, 2000


I am Dr. Steven Hyman, Director of the National Institute of Mental Health (NIMH). I am pleased to have this opportunity to provide a statement for the record concerning research and clinical issues surrounding the use of methylphenidate (Ritalin) in the treatment of attention-deficit/hyperactivity disorder, or ADHD. NIMH is the component of the National Institutes of Health (NIH) that is charged with generating the knowledge needed to understand, treat, and prevent mental illness across the lifespan. I have made childhood mental and behavioral disorders among the highest of NIMH research priorities. In my view, this is an area of investigation which is urgent, and one in which our search for answers must take into account very special ethical and scientific challenges.

Prevalence and Impact of Childhood Mental Disorders

The recent, landmark Surgeon General’s Report on Mental Health report estimates that some 20 percent of children and adolescents in the U.S. have mental disorders that result in mild functional impairment, and a smaller subset of children – between 5 and 9 percent – experience severe functional impairments. These children are severely handicapped in their ability to interact happily and healthily with their families and friends, to engage fully in school activities and to acquire the skills and knowledge that set the developmental path for a productive, satisfying adult life. For children, an untreated mental illness is doubly tragic because it may not be possible to recover the lost period of learning and social development needed to produce healthy, skilled, and productive individuals who can live up to their innate potential. Of course, untreated behavioral and emotional conditions in children can also markedly impair the ability of parents to work productively. The need for appropriate treatment of childhood mental illness is vital, and the payoff is immense, particularly given increasing evidence that the earliest possible diagnosis and intervention may minimize severity and ultimate functional impairment.

Often in public debate and in the media, the question is raised whether psychotropic medications are good for our children, given that childhood is a time of brain development and rapid behavioral change. I am concerned that labeling medication use as "good" or "bad" risks polarizing the necessary discussion. There exist in our country highly impaired children with attention-deficit/hyperactivity disorder, depression, bipolar disorder, and other illnesses for whom interventions other than medication have failed. There are also children who receive psychotropic medication for behavioral problems but who have not had appropriate work-ups. We need to ask whether children with emotional and behavioral disorders are getting proper evaluations by well-trained providers, proper interventions for their symptoms, and appropriate follow-up and management. It is true that we must be concerned about the impact of medication on brain development. Both of these issues – that is, the quality of mental health treatments and the developmental consequences of medications – are high on our research agenda. At the same time we must not forget that the impact of an untreated mental disorder on development of brain and behavior may have even more serious consequences.

Attention-Deficit/Hyperactivity Disorder and Methylphenidate

Attention-deficit/hyperactivity disorder (ADHD) is one of the most visible disorders seen in school-age children, with a prevalence rate in the population at large between 3 and 5 percent. I want to underscore this figure, because the limited data we have on community-to-community patterns of diagnosing and treating ADHD vary widely, perhaps to the detriment of under-treated and over-treated children alike. When doctors and other health care providers follow accepted practice guidelines, ADHD can be diagnosed in a reliable and valid way. ADHD usually becomes evident in preschool or early elementary years. It is a chronic condition that tends to persist into adolescence and, at times, adulthood. ADHD impairs the ability of children to function in school and at times, at home; understandably, it is associated with academic and occupational underachievement, low self-esteem, and increased rate of car accidents. Conduct disorder, anxiety and depression tend to co-occur with ADHD, and, when accompanied by conduct disorder, ADHD also is associated with delinquency and substance abuse.

Methylphenidate (MPH), commonly referred to as Ritalin after the commercial brand name, is a prescription medication approved by the Food and Drug Administration (FDA) approximately thirty years ago for the treatment of ADHD in adults and in children age 6 and older. MPH is highly effective in treating all the signs of ADHD, including hyperactivity, inattention, and impulsive behavior. Its efficacy has been documented by more than 160 controlled studies. In fact, the data supporting its efficacy constitute the largest body of scientific literature on any childhood behavioral disorder, involving the study of more than 5,000 children. Typically in these clinical trials, at least 80 percent of children with ADHD improve on MPH. The NIMH-funded Multimodal Treatment Study of Children with Attention-Deficit/Hyperactivity Disorder (MTA), which reported findings last December, involved the participation of 579 children, ages 7 to 9, making it the largest controlled study in child mental health. This study compared the effectiveness of single interventions (i.e., medication treatment or behavior therapy) with combined treatment (i.e., medication plus behavior therapy). The control condition – that is, the baseline for comparison – was the care children routinely receive in the community, in non-research settings. Results showed that MPH, when carefully dose-adjusted and monitored, is more effective than behavior therapy without medication; for some outcomes such as academic performance and familial relations the combined approach was favored by teachers and family members and it permitted lower doses of medication to be used.

Let me emphasize that MPH does not "cure" ADHD, but only controls the signs of the disorder. Because ADHD is a chronic condition, long-term treatment with MPH is usually needed. The effects of MPH beyond 14 months of administration have not been adequately studied. This is due to both the ethical and practical difficulties of conducting prolonged clinical trials in children. Naturalistic follow-up studies have not detected any long-term detrimental effects, however, and show that, when grown-up, ADHD children treated with MPH may have fewer car accidents, less tobacco use and substance abuse, and better social skills and self-esteem than untreated children. In 1998, NIMH and the National Institute on Drug Abuse organized a NIH Consensus Development Conference at which experts reviewed available data on abuse potential associated with ADHD and treatment with MPH. These experts found the weight of the evidence to be inconclusive, and called for more research.

An important aspect of treatment with MPH that has not been addressed adequately is whether long-term treatment leads to better academic achievement and occupational status. Indisputably, MPH improves daily academic classroom performance and "on task" behavior of children with the disorder. With proper medication, these children attempt more math and reading tasks; they are more attentive during class and are better able to absorb lessons being taught. But whether medicated children ultimately will achieve better educational outcomes is still in question. A follow-up of children who participated in the MTA study is being planned and is expected to provide clarification on some of these unresolved questions.

To recapitulate, data accumulated over 30 years of research and clinical use indicate that MPH is a safe medication when appropriately used for the treatment of ADHD. Certain side effects are common, such as decreased appetite and difficulties falling asleep at night, but they are usually mild and transient. More rare are stomachache, flat affect, compulsions, tic movements, and "zombie-like" appearance. The higher the dose the greater is the likelihood of these side effects. MPH has not been associated, as causal factor, to any life-threatening medical conditions. When used appropriately, it does not increase the risk of seizures or heart complications. Prolonged use may lead to slight, transient slowing in growth -- in one study, growth was about 2/3 of an inch less than expected over a 2-year period – but the ultimate height was not shorter than expected.

Appropriate Use of MPH Offers Little Potential for Abuse

MPH is a stimulant medication similar in pharmacological action to amphetamines. Amphetamine-like drugs certainly have abuse potential, and at high doses, in both humans and animals, produce dependence. However, the dosage equivalents that produce dependence in animal models or addiction in humans are far higher than those used to treat ADHD. Concerns that some children may abuse the medication by illicitly obtaining the medication and taking far more than a treatment dose are valid, but are not unique to this disorder and this treatment. When amphetamine-like stimulants are abused at doses that produce euphoria, they also produce tolerance leading, to steadily increasing doses. It is noteworthy that, in contrast, tolerance is generally not observed in the use of MPH or amphetamine derivatives to treat ADHD. Clearly, the higher doses that characterize abuse engage additional pharmacologic mechanisms than do the low doses that treat symptoms of ADHD. In other words, data regarding the consequences of illicit use of amphetamines should be understood as distinct from data regarding the therapeutic use of MPH in children with ADHD. NIMH hosted a research workshop in December 1999 to review these data and encourage more clinically appropriate use of animal models for the study of stimulant effects. A summary of this workshop is available on the NIMH homepage, at www.nimh.nih.gov/research/confsummaries.cfm .

The use of MPH has significantly increased during the last decade. This trend seems to reflect the increased interest in medical services for ADHD that has occurred in our communities. Although there have been no epidemiological studies in nationally representative samples that can inform on general patterns of use and misuse, we know that primary care physicians, such as pediatricians and family practitioners, are the most frequent source of prescriptions for MPH. As I noted above, some smaller studies have reported an over-prescribing of MPH among children in certain communities, while others have found an under-prescribing. Caucasian children appear to be more likely to be treated with MPH than African American children.

MPH has been shown to be effective also for children with conduct disturbances that are not necessarily accompanied by ADHD, such as aggression and antisocial behavior. Moreover, stimulant medications, such as MPH and dextroamphetamine, enhance cognitive performance including "on task" performance even in non-ADHD subjects. Though such uses of MPH do not reflect FDA-approved uses, it is possible that use to improve performance in individuals who would not meet strict diagnostic criteria for ADHD accounts for some of the purported over-prescribing of this medication. Research is needed to clarify patterns of care for children with ADHD and with milder behavioral symptoms, and to examine the attitudes of families, schools, and practitioners toward pharmacological interventions.

MPH in Very Young Children

Methylphenidate is approved by the FDA for use in children age 6 and older. There is evidence that it is being prescribed off-label also to younger children, and that this practice has increased over the last few years. We need to be aware that severe mental disorders are illnesses that affect a particular organ, the brain, and just as very young children are not immune from certain cancers or heart defects, neither are they immune from biologically based brain disorders. In many instances, use of medication is not only appropriate, but imperative. Since the first signs of ADHD often start in preschool years, especially for the more severe forms of the disorder, it is not entirely surprising that MPH is prescribed for these children. The increased use is worrisome, however, because the efficacy and safety of MPH – or, for that matter, the vast majority of prescription medications – in preschoolers have not been adequately investigated. Although there are seven controlled studies of MPH in children aged 3 to 6 years, these studies were relatively small in sample size, involving a total of 156 preschoolers, and did not extend beyond a few weeks of treatment. To obviate these limitations and provide adequate data on the safety and efficacy of MPH in younger children, NIMH will support a multisite trial at 6 universities. A large sample of carefully diagnosed preschoolers who suffer from impairing forms of ADHD will participate, with the active consent of their parents. The children in the study initially will receive a psychosocial intervention, and only those children who are not responsive to behavior therapy will be randomized to receive MPH or placebo. An extended follow-up is planned to detect long-term effects and need for continuous treatment. Let me note in this context that NIMH and our research community are exquisitely aware of the need for much more research on the long-term effects of any psychotropic medications on developing brains.

Conclusion

In closing, let me urge that the focus not be solely on whether medication use in children is "good" or "bad." The focus must be on the best ways to identify the real needs of children, to educate families, to monitor the selected treatments closely, and to assess the effects of treatment for a given child. We also need to ensure that that health care providers are educated about these issues, and that accurate information is available in diverse formats that will be useful to parents, teachers, day care providers, and others who deal directly with children on a regular basis.

Although we have much yet to learn about the developing brain and the causes, treatment, and prevention of mental and behavioral disorders in children and, indeed, across the lifespan, we must acknowledge the stunning scientific, clinically relevant progress that we have made in recent years. It is essential that as research continues, ambitious efforts must be undertaken to close the large gap between what we know at present and what actually is being done in practice in settings throughout the country.

Thank you.


January 22, 2003