Focus of Research for Clinicians

In response to a request from the public, a review was undertaken to evaluate the evidence regarding 1) the potential benefits and adverse effects associated with treatments for attention deficit hyperactivity disorder (ADHD) in preschoolers, 2) the long-term effectiveness of interventions for ADHD in individuals 6 years of age and older, and 3) the variability of prevalence, diagnosis, and treatment associated with potential moderating factors. The systematic review included 223 studies published from January 1980 through May 2010. The full report, listing all studies, is available at www.effectivehealthcare.ahrq.gov/adhdtreatment.cfm. This summary is provided to inform discussions with patients and caregivers of options and to assist in decisionmaking along with consideration of a patient or caregiver’s values and preferences. However, reviews of evidence should not be construed to represent clinical recommendations or guidelines.

Background

ADHD affects children of all ages, and approximately 5 percent of children worldwide show impaired levels of attention and hyperactivity. There are three subtypes of ADHD: 1) predominantly inattentive, 2) predominantly hyperactive-impulsive, and 3) combined inattentive and hyperactive. Boys are classified with ADHD about twice as frequently as girls and young children about twice as frequently as adolescents. Clinically significant ADHD is often associated with concurrent defiant and disruptive behaviors, temper tantrums, anxiety, low self-esteem, and learning disabilities.

ADHD is most commonly identified and treated in elementary school (ages 7 to 9) but can begin before children enter school. There is an increasing interest in identifying children who show signs of ADHD at a very young age in order to treat them as early as possible and thereby diminish social and academic repercussions. Overall, levels of symptoms of hyperactivity and impulsiveness decrease with age; however, many children with ADHD continue to show impairment relative to same-age peers throughout adolescence and into adulthood.

Interventions for ADHD include a range of pharmacologic and nonpharmacologic options. Psychostimulants and nonstimulant medications are often prescribed. Children with ADHD and their families may also receive nonspecific psychosocial support, counseling, and advice or support through standardized programs for parents and children. Children with ADHD may receive academic tutoring and coaching, both within and outside of school settings. There is a need for a systematic evaluation, including long-term effectiveness, of both the pharmacologic and nonpharmacologic interventions.

Conclusion

The number of ADHD cases identified has increased over time. Children from lower socioeconomic status (SES) households are diagnosed with ADHD more often than children from higher SES households. However, children from higher SES households are more likely to receive treatment than those from lower SES households.

High-strength evidence shows that parental behavior training is efficacious for preschoolers; however, parents often drop out. Evidence is insufficient to know if school-based interventions are effective for preschoolers, and there are very few data on the outcomes related to the use of ADHD medications other than methylphenidate (MPH). For children 6 years of age or older, evidence is insufficient to know if nonpharmacologic treatments alone are beneficial in the long term. Evidence shows that ADHD medications are safe and effective for children ages 6 and older. For both preschoolers and children over the age of 6, long-term effectiveness and adverse effects are not well studied. Which interventions are best for which children and which behavior training programs are most suitable for parents are unknown. Limited evidence suggests that some subgroups of children may benefit more from combined medication and behavioral interventions than from medication alone. It is unclear how long treatment may be required, of what type, and for which subgroups.

More adverse effects were reported in preschoolers than in elementary school children. Moodiness and irritability often lead to discontinuation of treatment with MPH. Although children taking ADHD medications appear to have diminished growth rates, some studies found that the children may eventually catch up on their growth over time.

Clinical Bottom Line

Strength of Evidence Scale

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High:		There are consistent results from good-quality studies. Further research is very unlikely to change the conclusions.
Moderate:		Findings are supported, but further research could change the conclusions.
Low:		There are very few studies, or existing studies are flawed.
Insufficient:		Research is either unavailable or does not permit estimation of a treatment effect.

Adverse Effects

Although not critically evaluated within the report, general research on adverse effects associated with ADHD treatments suggests the following:

• Psychostimulants and atomoxetine may cause insomnia, appetite loss, tiredness, social withdrawal, and abdominal pain.
• Psychostimulants and atomoxetine may also cause a modest increase in average blood pressure and average heart rate in some children and adolescents.
• Children or adolescents taking atomoxetine may be more likely to think about suicide than children who do not take it.
• More adverse effects were reported in preschoolers than in elementary school children.
• Moodiness and irritability often led to discontinuation of treatment with MPH.
• ADHD medications appear to have a small but distinct dose-related impact on growth rates in children. Some studies found that although children taking ADHD medications appear to have diminished growth rates, they may eventually catch up on their growth over time.
• Extended-release guanfacine was not well tolerated, with less than 20 percent of study participants completing the treatment at 12 months. Adverse effects include somnolence or sedation, fatigue, headache, and possible weight gain. Abnormal or worsening electrocardiographic changes judged clinically significant in 1 percent of patients suggest that monitoring of cardiac status is indicated.
• Safety investigations from observational studies and administrative databases did not provide conclusive evidence for cardiovascular or cerbrovascular adverse effects.

ADHD Medications

Variability in Prevalence, Clinical Identification, and Treatment of ADHD in Children

The table below lists conclusions on the variability in prevalence, diagnosis, and treatment of ADHD in children associated with potential moderating factors. For these conclusions, the literature was searched using the methodology of a systematic review; however, the selection of papers for inclusion was not subject to the same constraints as the rest of the report. Other relevant papers were added via peer review feedback. These findings were included to provide context, and any studies considered pertinent to the topic of variability in ADHD prevalence, diagnosis, and treatment were included.

Gaps in Knowledge

• Data regarding the long-term effectiveness or possible adverse effects for all ADHD treatments are scarce. The few long-term studies that are available are mostly of medications.
• Studies are needed to compare the effectiveness of diagnosis and treatment approaches for girls, as the current evidence is based predominantly on boys.
• Other populations that need further research include ethnic minorities and families of low SES.
• Little specific information is available about outcomes for children with comorbid learning disabilities, language impairments, and reading or mathematics disorders.
• Investigations of parental preferences regarding behavior training are needed to determine if parental completion rates for training can be improved.
• Very few studies examined psychostimulant use for preschoolers.
• Very few randomized clinical trials offer information about parental training interventions designed specifically for preschoolers with ADHD.

What To Discuss With Your Patients and Their Caregivers

• How ADHD affects children or adolescents and their families.
• Potential benefits associated with nonpharmacologic interventions such as parental behavior therapy programs.
• Potential benefits and adverse effects associated with psychostimulants and nonstimulants. In choosing medications, it is useful to discuss dose timing and monitoring in order to make choices most compatible with treatment goals and patient schedules and lifestyle.
• Patient and parental preferences regarding diagnosis and treatment options, including pharmacologic and nonpharmacologic interventions.
• How they can access information from the National Resource Center on ADHD about diagnosis and treatment, educational programs, public benefits, and other issues. The Center is supported with funding from the Federal Government through the Centers for Disease Control and Prevention (CDC). ADHD information can be accessed online at www.help4adhd.org or by phone at 800-233-4050.

Resource for Patients

Treatment Options for ADHD in Children and Teens, A Review of the Research for Parents and Caregivers is a free companion to this clinician research summary. It can help patients, parents, and caregivers talk with their health care professionals about the many options for diagnosis and treatment. It provides:

• A description of ADHD and its symptoms
• Descriptions of the types of treatments and potential side effects
• Simplified summaries of the research on the effectiveness of each treatment option
• Questions to guide a discussion about treatment options between parents or caregivers and their child’s doctor

Ordering Information

For electronic copies of Treatment Options for ADHD in Children and Teens, A Review of the Research for Parents and Caregivers, this clinician research summary, and the full systematic review, visit www.effectivehealthcare.ahrq.gov/adhdtreatment.cfm. To order free print copies, call the AHRQ Publications Clearinghouse at 800-358-9295.

Source

The information in this summary is based on Attention Deficit Hyperactivity Disorder: Effectiveness of Treatment in At-Risk Preschoolers; Long-term Effectiveness in All Ages; and Variability in Prevalence, Diagnosis, and Treatment, Comparative Effectiveness Review No. 44, prepared by the McMaster University Evidence-based Practice Center under Contract No. MME for the Agency for Healthcare Research and Quality, October 2011. Available at www.effectivehealthcare.ahrq.gov/adhdtreatment.cfm. This summary was prepared by the John M. Eisenberg Center for Clinical Decisions and Communications Science at Baylor College of Medicine, Houston, TX.