Attention-deficit/hyperactivity disorder (ADHD) diagnoses are on the rise, and the number of new cases in adolescent females has outpaced that of males, according to a new report.
The study, published in The Journal of Clinical Psychiatry, reveals that diagnoses of ADHD has risen from 7.8% in 2003 to 11% in 2011, resulting in an overall prevalence of 5% to 11% in children aged 5 to 17 years.
The report outlines prevalence among ethnic and socioeconomic groups, revealing that prevalence is growing in demographic groups that were previously in the minority for ADHD diagnoses.
Attention-deficit/hyperactivity disorder is the most commonly diagnosed mental disorder in childhood, and is defined as a persistent pattern of inattention and/or hyperactivity and impulsivity that negatively impacts school and educational or work performance. It is one of the few mental health disorders where childhood onset is part of the diagnostic criteria, notes one of the study authors, Sean Cleary PhD, MPH, associate professor of epidemiology and biostatistics at the School of Public Health and Health Services and the director of the MS and PhD Programs in epidemiology at George Washington University in Washington, DC.
Attention-deficit/hyperactivity disorder is most commonly treated by a combination of drug therapy, behavioral parent training, behavioral classroom modifications, and sometimes individualized education programs, according to the report. While these interventions are generally effective, symptoms of ADHD can persist into adulthood, Cleary writes, leading many healthcare professionals to view ADHD as a lifelong disorder.
The paper notes that the increase of ADHD prevalence among school-age children is well-documented, despite variances in the estimates of prevalence amongst government agencies, but that its cause is unknown. Some believe that the rise in ADHD cases may be attributed to changes in diagnostic criteria and increased public awareness, especially since many cases of ADHD are parent-reported. Black, Hispanic, and “other” racial groups were significantly less likely to have parent-reported diagnoses, according to the report.
Prevalence of parent-reported ADHD in children aged 5 to 17 years has risen from 8.4% in 2003 to 12% in 2011, corresponding to a 43% increase based on population size, according to the report.
The increase in prevalence among parent-reported ADHD in Hispanic and other non-English speaking populations—groups that experienced the largest increases in prevalence from 2003 to 2011—may reflect the increasing availability of Spanish-language mental health resources, as well as greater cultural acceptance of illness within those populations, according to the report.
Overall, Cleary’s report indicates that was a 42.9% increase in ADHD prevalence from 2003 to 2011 across all subgroups, except for small declines among uninsured children and children living in unsafe neighborhoods. Some of the largest increases, Cleary says, occurred in Hispanic populations (83.3%), non-English speaking groups (107.1%), and in children whose parents were in “other” parental marital situations (70.7%).
Generally, the highest prevalence of ADHD is in white children, and the lowest in Hispanic children, according to the report, with evidence suggesting that sociodemographics and language barriers play a role.
The highest prevalence rates are generally found in male children aged 10 to 17 years, among children with single mothers, among those living below 200% of poverty level, or those with no health insurance, while lower prevalence was found in non-English speakers.
The influence of socioeconomic status on ADHD diagnoses is of particular concern, according to the study authors, given the fact that the percentage of children living at or below 100% of the poverty level grew by 26.4% from 2003 to 2011.
Overall prevalence among various demographic groups between 2003 and 2011 increased by 42% for whites, 66% for blacks, 79% for Hispanics, and 31% among “other” racial/ethnic groups, according to the report.
In terms of gender, the study revealed that ADHD prevalence also increased 55.3% in females during the study period, compared with 39.8% in males.
“Although ADHD is more likely to be diagnosed in boys, parent-reported prevalence for girls has risen from 4.7% in 2003 to 7.3% in 2011; this corresponds to a 55.3% increase, compared to a 39.8% increase in boys,” the report states. “This may reflect an increased understanding of ADHD symptoms in girls, which can manifest differently than in boys.”
Pediatricians must recognize that ADHD symptoms vary by gender, and suspected cases require careful assessment, Cleary says.
“Females may exhibit more internalizing symptoms—being withdrawn, verbal aggression such as teasing, name calling—that are often overlooked because they are not the typical symptoms that manifest in males,” says Cleary. “A lack of diagnosis may lead not only to current difficulties in school, but also to long-term challenges into adulthood.
Later diagnoses are also on the rise, with a 52% increase from 2003 to 2011 among children aged 15 to 17 years; compared to a 46.5% increase among children aged 10 to 14 years; and a 33.3% increase among children aged 5 to 9 years over the same period.
“The larger increase in ADHD prevalence for this age group is of concern because the effects of ADHD are often expected to weaken in later adolescence or post-adolescence, and many diagnosed children will discontinue medication around this time,” the report states. “Although it is speculation to give reason for this rise, factors that may play a role include the greater acceptance of adult-ADHD as a legitimate disorder, increased academic pressures for adolescents, or simply the aging of child populations diagnosed in the early 2000s.”
The increased prevalence of ADHD and the resulting increased demand for special-education programs and healthcare resources has led to a call by may healthcare professionals to employ stricter diagnostic procedures to combat over-diagnosis, says Cleary. The drain on healthcare resources can be illustrated by the fact that, since 1998, at least 14 new brands of ADHD medications have been approved by the U.S. Food and Drug Administration (FDA) compared with a mere 9 brand approvals between 1936 and 1998.
The American Academy of Pediatricians (AAP) currently recommends screening any child aged between 4 and 18 years presenting with behavioral or academic problems for ADHD based on reports from parents, teachers, and other school or social workers while also ruling out any alternate causes for the behavioral or academic disturbance. Treatment recommendations include behavioral modification in preschool-aged children, with medication therapies beginning at school age through adulthood. Medications are most effective when combined with behavioral therapy, according to the American Academy of Family Physicians.
The AAP has also called for further research into diagnostic tools that evaluate the severity of a child’s ADHD; the efficacy of non-FDA approved medications; the evaluation of the efficacy of school-based interventions; and better communication tools between schools and healthcare providers.