The PA-IMH breakfast seminar audience on Jan. 7, 2015, heard a presentation by Nathan Blum, M.D., Professor of Pediatrics at CHOP, on aspects of Attention Deficit/Hyperactivity Disorder (ADHD) in preschool children. Dr. Blum addressed questions of both theoretical and practical importance: 1) at what age is it possible to diagnose ADHD?, 2) when preschool children are diagnosed with ADHD, is the diagnosis associated with impairment?, 3) how do the symptoms and diagnosis change with age?, and 4) when ADHD has been diagnosed in young children, how should we treat the disorder? As Dr. Blum noted, the answers to these questions are not necessarily the same for preschoolers as they are for school-age children. The nature of the answers is also complicated by differences between the criteria for diagnosis given by DSM-IV and DSM-5, and by the fact of subtypes of ADHD.
DSM-IV offered mixed messages about early diagnosis of ADHD, sometimes suggesting that age 4 or 5 years was the youngest period at which an ADHD diagnosis could be made, but at other times referring to the attentional capacities of toddlers. DSM-5 commented that although parents may observe excessive motor activity in toddlers, there is so much normal variability in attention and impulsiveness that other symptoms may not be able to be distinguished until age 4. In line with this observation, the American Academy of Pediatrics now recommends that children with symptoms of ADHD be evaluated from age 4 onward. At age 3, 3% of boys and less than 1% of girls have already been diagnosed with ADHD.
Do these symptomatic children show other impairments? What happens to them as they get older? Younger children diagnosed with ADHD were also seen to have problems of slowed language development, and as they moved into the school years they had lower reading scores than others, but their math scores were not different from those of non-ADHD children. By age 11, about 50% in one study no longer met criteria for attention disorders of for other mental health problems.
Which were the children who, after being diagnosed with ADHD at age 3, later did not show symptoms of the disorder? Dr. Blum pointed out that although it is possible to describe differences between groups who were more or less likely to continue to show symptoms, there is no way to identify an individual who will “grow out” of ADHD symptoms. The period between 3 and 4 years is the time when “growing out” is likely to occur if it is going to do so, with about 50% of symptomatic 3-year-olds improving by age 4.
For preschool children who persisted with symptoms of ADHD, a number of factors were associated with the persistence, but no single factor or pattern predicted what would happen to an individual. Children with persisting ADHD were more likely to have had sleep problems at 24 and 36 months and to have lower language ability. They had more negative behaviors even in infancy, and more negative parenting behaviors were likely to be present. There were more externalizing, disruptive behaviors, and also more internalizing behaviors such as anxiety and negative moods. Family incomes and parental educational levels were lower among children with persistent ADHD. Those children also were more likely to be exposed to parental psychopathology, and 25% of parents of ADHD children have ADHD themselves.
Dr. Blum also discussed some issues about treatment of ADHD in preschool children. He pointed out that of the available treatments, behavior therapy and methylphenidate (Ritalin), neither treatment is specific to ADHD, but is instead directed at symptoms that cause problems. The American Academy of Pediatrics has recommended that the first choice of treatment is evidence-based behavioral therapy. If this is not sufficient, or if behavioral therapy is not available where the family lives, or acceptable to the family, methylphenidate may be used after weighing the risks of starting the medicine at an early age versus delaying treatment.
The side effects of methylphenidate in preschoolers with ADHD are more worrisome than they are in school-age children. In one study, 11% stopped the medication because of side effects, more than half of these being irritability and emotionality, and others being decreased appetite, tics, insomnia, and occasionally other problems. In the same study, preschool children grew an average of 1.38 centimeters a year less than expected; in another study, the growth lag in school-age children was only 0.86 cm. In addition to these problems, it was notable that while 22% of children on methylphenidate met the criteria for a significant improvement, 13% of those on a placebo also met the criteria, leaving a relatively small difference to be attributed to the medication.
Parent training has also resulted in some improvements in preschool ADHD symptoms, but these do not occur in all children or by all measures. For example, in a study of the New Forest Parenting Program, parent ratings of children’s behavior improved, but observational measures did not change. This program’s positive effects occurred when training was provided by home visitors with a mental health background, but not when it was done by medically-trained visitors who had been trained in the parenting program.
In conclusion, Dr. Blum offered the following summary statements: Preschoolers with ADHD have significant functional impairments; behavioral treatments and medication can both cause improvement, but less than half the children are excellent responders; and methylphenidate side effects may be more significant in preschoolers than in school-age children.