Behind the label: ADHD over 30 years
To mark our 30th anniversary, Infectious Diseases in Children will be examining some of the chronic conditions and infectious diseases that have impacted pediatric care over the past 3 decades.
Although childhood hyperactivity and inattention have been described in medical literature since as early as the 18th century, it was not until 1987 that the term “Attention-Deficit Hyperactivity Disorder” appeared in the Diagnostic and Statistical Manual of Mental Disorders — the last in a century of terminological shifts pertaining to a neurodevelopmental condition that was only starting to be understood.
ADHD is now defined as a pattern of inattention and/or hyperactivity-impulsivity that negatively impacts childhood development or functioning in multiple domains. Jennifer Kaminski, PhD, with CDC’s National Center on Birth Defects and Developmental Disabilities, told Infectious Diseases in Children that ADHD has gained medical credibility in the last 3 decades, partly as a result of neuroimaging studies that provide visible evidence of the ways ADHD affects the brain.
“Most experts now agree that ADHD exists and that it is a distinct condition with core features that are different from other diagnoses,” Kaminski said.
At the same time, diagnosis, treatment and perceptions of ADHD are complicated by the nature of the disorder: it cannot be definitively diagnosed by a test; it exhibits symptoms that overlap with other mental and behavioral conditions; and it occurs along a spectrum ranging from mild to severe.
Changing the treatment landscape
Paul Lipkin, MD, associate professor of pediatrics at Kennedy Krieger Institute at Johns Hopkins University School of Medicine, told Infectious Diseases in Children that the advent of behavioral therapy, which can be delivered by parents, in schools, and by children themselves, is one of the most significant advances in ADHD treatment over the past 30 years. Using cognitive behavioral techniques, he said, “the child is taught how to recognize certain problematic situations and how to intervene on their own behalf to try to minimize the problems their behaviors can cause.”
In addition, the last few decades have seen significant advances in the preparations of first-line stimulant drugs. “Previously, stimulants were all short-acting preparations which lasted 3 to 4 hours,” Ruth E.K. Stein, MD, attending physician at Children’s Hospital at Montefiore, told Infectious Diseases in Children. “We now have a whole cadre of long-acting stimulants that can carry most kids through the school day.” As far as delivery methods, liquid preparations and transdermal patches now offer alternatives to pills.
The medications themselves, however, have changed little over several decades. Amphetamines have been used since the 1930s to treat behavioral disorders, and methylphenidates have been used since the arrival of Ritalin in the 1950s.
“We have not found any medications that are better than those, nor have we developed variations of those medications that have minimized their adverse effects—such as changes in appetite, insomnia, headaches and tics,” Lipkin said.
By the numbers
In 2011, according to a CDC survey of parents, approximately 11% of children aged 4 to 17 had ever been diagnosed with ADHD. This represents a 42% increase over the rate of 7.8% reported in 2003, and an increase of approximately 5% per year.
“We do not know yet what is causing those increases,” Kaminski told Infectious Diseases in Children. She said that, although it is possible that actual prevalence rates are on the rise, it is also possible that, in the past, cases were going undiagnosed, especially among children with milder symptoms.
“Thirty years ago, the children who were being recognized and treated were most typically boys with hyperactivity and disruptive behavior,” Lipkin told Infectious Diseases in Children. Today, he said, ADHD is being recognized in children of both genders whose level of impairment is less severe.
Shifting diagnosis and treatment settings may also have an impact. Once the province of psychiatrists and neurologists, ADHD diagnosis and treatment is now handled largely by pediatricians. “Starting back about a decade ago, we had more than half of pediatricians treating ADHD in their offices,” Stein told Infectious Diseases in Children. “That makes access to care much easier.”
Some reports question the accuracy of these data on rates of diagnosis. Multiple meta-analyses assessing the prevalence of ADHD have concluded that actual prevalence has not increased since the 1980s and that rates of diagnoses are quite similar throughout the world.
“Until we have more detailed surveillance and research, we are left unfortunately with more questions than answers about these trends and what is causing them,” Kaminski said.
Regardless of the precise rates of prevalence and diagnosis, the increasing recognition of ADHD, especially in children with mild manifestations, has raised some alarm.
“There still remains a fair amount of public skepticism about whether mild attentional problems should be defined as an abnormal condition and treated with medication,” Lipkin said. He sees things from a different angle: “If anything, we probably undertreated people 30 years ago — We are probably benefiting more people by offering treatment that was previously withheld from them.”
Managing ADHD among young children
The symptoms of ADHD are often most obvious when a child enters school. However, Lipkin told Infectious Diseases in Children that, about 20 years ago, “there was a recognition that children didn’t suddenly develop this when they went to school—that there were some children who had these problems earlier.” Accordingly, rates of ADHD diagnosis among very young children have increased.
For children younger than 6 years, AAP recommends behavioral therapy as the first line of treatment, with medication advised only if behavioral therapy fails to provide significant improvement.
“The side effect profile [for ADHD medications] is a little bit worse in young children,” Lipkin said. “Young children have a higher likelihood of developing some sort of short-term adverse effect from the medication, and the predictability of dosing that we see in school-age children is not as predictable in young children.”
Despite AAP recommendations, only about half of young children with ADHD are reported to receive any form of psychological services, whereas three in four receive medicine.
Kaminski told Infectious Diseases in Children that multiple factors contribute to these trends. Some doctors and parents may lack information about recommended treatment for young children, whereas some may prefer medication for the convenience and speed with which results are seen. Additionally, she said, “we know that the behavior programs are not available everywhere. Even if you have a family and a clinician who understand the guidelines and are invested in doing the behavior therapy, they might not be able to find it or access it.”
Looking to the future
Diagnosing and treating ADHD is complicated by the fact that that other conditions can both mimic it and coexist with it.
“One of the major challenges is to differentiate the child who has primary anxiety, or post-traumatic stress disorder, or has had some terrible event in his life that is contributing to his impulsivity, his hyperactivity, or his inattentiveness,” Stein said. “The most important tool, which unfortunately is a rarity these days, is the time to do a thorough history and explore the conditions under which these symptoms first appeared and how they have progressed.”
Further, social and environmental circumstances can impact ADHD’s severity. Kaminski noted that although “we know that there are some core cognitive struggles and deficits” associated with ADHD, “we also know that social and environmental factors can influence how impairing these core symptoms are.”
Effective treatment of ADHD requires understanding and addressing myriad factors in a child’s life, which is a challenge for time- and resource-limited physicians, families, schools, and communities. But, Kaminski said, “if we can modify those social and environmental factors, we can contribute hugely to the child’s success.” — by Sarah Kennedy
- CDC. ADHD Data and Statistics. Accessed 6 March 2017. https://www.cdc.gov/ncbddd/adhd/data.html
- CDC. Key Findings: Trends in the Parent-Report of Health Care Provider-Diagnosis and Medication Treatment for ADHD: United States, 2003-2011. https://www.cdc.gov/ncbddd/adhd/features/key-findings-adhd72013.html
- CDC. Timeline: ADHD Throughout the Years. Accessed 9 March 2017. https://www.cdc.gov/ncbddd/adhd/timeline.html
- Lange KW, et al. Atten Defic Hyperact Disord. 2010;doi:10.1007/s12402-010-0045-8.
- Polanczyk GV, et al. Int J Epidemiol. 2014;doi:10.1093/ije/dyt261.
- Thomas R, et al. Pediatrics. 2015;doi:10.1542/peds.2014-3482.
Disclosures: Lipkin receives support from the Simon Foundation and Patients and Outcomes Researchers (PECOR). Kaminski and Stein report no relevant financial disclosures.