Update on ADHD 2005

UPDATE ON ADHD 2005

Sam Goldstein, Ph.D.
November, 2005 Copyright © 2005

In the past two months, three important reports were issued by diverse groups concerning the diagnosis and treatment of ADHD. First, the U.S. Centers for Disease Control issued a report based on data collected in 2003 concerning the incidence of and treatment for ADHD state by state in America (CDC, 2005, www.cdc.gov/mmwr). Not surprisingly, incidence rates varied significantly from a low of approximately 5% to a high of 8% in children ages 4 to 17 years old. There appeared to be a consensus that regardless of incidence rate, approximately half had or were receiving medication treatment for the condition. The second report, issued by Medco Health Solutions, focused almost exclusively on the growth of the diagnosis and treatment of ADHD in adults (Medco, 2005). Finally, the third report published by the Oregon Health and Sciences University Drug Class Review Program on ph armacologic treatments attempted to examine the comparative effectiveness and tolerability of medications used to treat ADHD (McDonagh and Peterson, 2005). In this month's article, I will briefly summarize these latter two studies and offer a number of explanations I believe are responsible for the continued increase in the diagnosis and use of stimulant medications to treat ADHD.

Growth in Adult ADHD Diagnosis and Treatment

It has been estimated that approximately eight million adults in the United States suffer from ADHD, making it the second most common psychological problem in adults after depression. Yet, it is estimated that only 15% are reported to know that they have the condition. In a report issued in September, Medco Health Solutions summarized a survey of 2.4 million individuals across the life span relative to diagnosis and treatment for ADHD. Medco is a Fortune 500 company with reported revenues of 35 billion dollars in 2004. http://www.medco.com Their home page describes them as a "leader in managing prescription drug benefit programs that are designed to drive down the cost of ph armacy health care for private and public employers, health plans, labor unions and government agencies of all sizes." Medco operates the nation's largest specialty ph armacy operation, including mail order and internet ph armacies.

The primary force driving this survey was a treatment cost analysis. Medco reported nearly 78% of all prescriptions in 2004 dispensed for ADHD were brand name medications reflecting a nearly 30% increase in the use of brands versus generics. New preparations (e.g., Strattera) and delivery systems (e.g., Concerta) contributed to this rise. This led to nearly a tripling in the cost of medication treatment for ADHD. The shift away from generic drug use back to brand name drugs costing more money in combination with the equivocal findings comparing one medication treatment to another for ADHD in the Oregon Health and Sciences University report, will likely spur an increased push by health care providers for patients to use generic rather than brand name preparations.

In a nationwide analysis of 2.4 million subscriber prescription data, Medco reported prevalence rates of medication used to treat ADHD in 2004 of 3.41% for boys and 1.23% for girls below nine years of age. Growth among the adult population between 2000 and 2004 significantly outpaced the pediatric group by a margin of nearly 2 to 1. There was a four fold increase in the amount of money spent between 2000 and 2004 on medication to treat adult ADHD. The prevalence of ADHD medication used in 2003 was 1.1% and grew to 1.3% in 2004, a nearly 25% increase. This ranks second among all drug categories with only growth in rheumatologic drug users being greater. The greatest growth, 117% in the number of adult medication users for ADHD under age 65 was seen in a portion of the central region of the United States, including the states of Kentucky, Tennessee, Alabama and Mississippi. In the CDC Report concerning diagnosis and treatment of ADHD, these were among the states with the highest percentages of diagnosis and treatment. This region also had the largest increase in children ages 19 and under taking medication for ADHD, rising 70% from 2000 to 2004. Medco also reported that between 2000 and 2004 the number of children under the age of 9 using medication for ADHD grew almost 75% and spending increased five fold with males three times more likely to be taking medication for ADHD than females in this age group. Between 2000 and 2004 the number of adults between the ages of 20 to 44 taking medication for ADHD increased from 1 out 200 to 1 out of 100. Among females, ages 20 to 44, the use of ADHD medication more than doubled over the four year analysis period, a growth rate 21% greater than males. In 2004, the use of ADHD medications for adult women between the ages of 20 to 64 was equal to that of men. Yet, it is important to reiterate that even taking a very conservative estimate of 3% to 5% of the total population meeting diagnostic criteria for ADHD, half are still not receiving treatment, when treatment is defined as the use of research demonstrated medications for ADHD.

Oregon Health and Sciences University Report

The Oregon Evidence-Based Practice Center at the Oregon Health and Science University works to make information available regarding the comparative effectiveness and safety profiles of different drugs within ph armaceutical classes. The Center acknowledges that their reports are not usage guidelines nor should they be read as an endorsement of, or recommendation for any particular drug or approach. In September, 2005 the Center released a 100 plus page report on their drug class review of ph armacological treatments for ADHD. These findings, if able to stand the rigor of peer review, raise important questions about the comparative efficacy of the medications used to treat ADHD and their short versus long term impact.

The drug class review asked three key questions.

1. What is the comparative effectiveness of different ph armacologic treatments for attention deficit disorders?
2. What is the comparative tolerability and safety of different pha rmacologic treatments for attention deficit disorders?
3. Are their subgroups of patients based on demographics (e.g., age, racial background, gender, etc.), other medications, or comorbidities for which one ph armacologic treatment is more effective or associated with fewer adverse events?

It is important to note that this review did not question whether stimulants were effective for the treatment of ADHD and in fact reported that the overall response rate of stimulants for ADHD appears to be in the range of 60% to 80%. The authors identified over 2,000 citations from literature searches and reviews of reference lists. After applying eligibility and exclusion criteria to the titles and abstracts of the studies reviewed, the authors obtained full paper copies of 514 publications, making this the largest review on drug class effectiveness for ADHD. After reapplying the criteria for inclusion, the authors ultimately included 180 publications. Based upon review of these 180 publications, Dr. Marian S. McDonough and Ms. Kim Peterson reported:

1. Comparative effectiveness trials of drugs used in the treatment of ADHD are limited and generally do not make a case that one medication is better than another.
2. Good quality evidence on the use of medication to affect long-term outcomes relating to global academic performance, consequences of risky behavior, social achievement, etc. is lacking.
3. The evidence for comparative efficacy and adverse events of drugs used for the treatment of ADHD is severely limited by small sample sizes, very short durations of study, lack of studies measuring functional or long-term outcome. These findings are not unexpected as many drug studies for ADHD are funded by their manufacturers with the goal of demonstrating safety and short term efficacy to support FDA approval. Methods of measuring symptom control varied significantly across these studies. A crossover design was frequently used with few studies analyzing the effect of order of administration of drugs. Those that did found a significant effect. No head-to-head efficacy trials were reported to be of good quality. The small numbers of individuals in these trials limited the ability to demonstrate a difference between drugs, if one exists.
4. In addition to small sample sizes restricting statistical analysis, the authors noted other factors impeding the ability to draw conclusions from many of these studies, including:
   (a) Variation in diagnostic criteria and/or level of severity required for enrollment.
   (b) Proportions of patients with various subtypes of ADHD.
   (c) Proportions of patients with various comorbidities.
   (d) Lack of inclusion of a variety of ethnic groups.
5. Finally, although the authors, as noted, report significant benefits of drugs used to treat ADHD, they also note definitions of response rates varied and may not be comparable across studies. Depending on the definition used, there was a lack of clarity on the relationship of response rate to clinical significance. Additionally, response rates of non-stimulants varied but the range in placebo controlled trials was reported to be similar to that found with stimulants. Significant variation in the methods of assessment and definitions of response were reported to be the most likely reasons for this wide variation.

The message from this industrious review is clear, there is much research to be done relative to the comparison of the efficacy of various drugs used to treat ADHD but more importantly, in developing an understanding of the difference between drug effects leading to symptom relief versus drug effects leading to significant positive long-term outcome.

What Does It All Mean?

First, these three reports are not indicators of a conspiracy nor that something insidious is taking place. In fact, these reports reflect the increasing identification of those with ADHD and subsequent treatment. They also reflect a need for continued and thoughtful research in this area. However, these reports can be easily misused by those with agendas about ADHD, the diagnosis and treatment of the mental health field in general. Why are we witnessing an increase in the diagnosis of ADHD and subsequent treatment? Here are my four explanations:

1. Effective treatments are embraced. When an effective treatment enters the marketplace and/or is well promoted to professionals and the general public it is likely to be embraced and the numbers of treated individuals will increase significantly. This has been documented time and time again including over the counter preparations (e.g., Vitamin C to treat the common cold), medical conditions (Imitrex to treat migraine headache) and psychiatry (Risperdal to treat Schizophrenia and related problems). In these and other cases the rate of individuals receiving treatment increases dramatically over a short period of time as do health care costs. Thus, it is not surprising given the demonstrated effectiveness of stimulant medications in treating ADHD that numbers have and will increase. This phenomena was first observed as a treatment for ADHD in children. More recently, as noted by the Medco survey, a similar phenomena is being observed in adults with ADHD.
2. Time and effort impact treatment choice. When a condition can be treated in a number of different ways but those treatments vary in their timeline for effectiveness and consistent effort required by the patient or others, patients and/or their caretakers will gravitate towards those treatments that are quickest and require less effort. Medication is an effective treatment for ADHD. Some researchers demonstrate that for mild to moderate ADHD there are also effective psychosocial treatments for ADHD. However these can be demanding of time, require consistent application over long periods and are costly. Though medication treatment may carry more potential risks than psychosocial intervention for ADHD, the benefits are quick, immediate and often answer the prayers of frustrated parents and struggling adult patients.
3. Some symptoms of ADHD mirror the human condition. When some symptoms of a condition, in this case inattention, restlessness and impulsive behavior are experienced to a less impairing degree by the general population, many without the condition in times of struggle or stress may believe they possess the condition and will therefore seek treatment. The significant geographical variation in diagnosis and treatment of ADHD makes a strong argument that diagnostic criteria are not being consistently nor stringently applied likely resulting in false positive diagnoses. This is not to suggest that ADHD is over-diagnosed. In fact the data argues that a significant percentage of children and adults with the condition remained undiagnosed, but that individuals without the condition may be wrongly diagnosed.
4. The symptoms of ADHD are to some extent generic. The core symptoms of ADHD in various combinations or individually present in other major psychiatric conditions, including depression and anxiety. Though stimulants may have a mild, universal enhancing effect they have not been demonstrated to be clinically effective for these other conditions. However, individuals with these other conditions, based on what they read, hear or see in the media, may believe their symptoms reflect ADHD and therefore seek out treatment. Again, failure to stringently apply diagnostic criteria may lead to false positive diagnoses.

I urge researchers and clinicians in the field of ADHD to address these issues; in particular, attending to rates of diagnosis, effectiveness of treatments over time and an appreciation of the distinction between symptoms and impairment. These three reports remind us that we have miles and miles to go before we rest. Controversy in ADHD must not be reduced to opinion based debates about etiology, definition, evaluation and treatment but focus upon the importance of understanding human development and behavior. We must appreciate and understand the limitations suffered by individuals with ADHD, a neurologically based but environmentally driven condition. Most importantly, however, our work must be about providing appropriate care and assistance to people with ADHD throughout the life span.

References

Center for Disease Control (2005). Morbidity and Mortality Weekly Report, 54(34). www.cdc.gov/mmwr

McDonagh, M.S., & Peterson, K. (2005). Drug Class Review on Ph-armacologic Treatments of ADHD: Final Report. Portland, OR: Oregon Evidence-Based Practice Center, Oregon Health and Science University.

Medco Health Solutions (2005). ADHD medication use growing faster among adults than children. New Research. www.medco.com