Do American Parents Overreport Symptoms of ADHD?

A new study finds country differences in parental reporting of ADHD symptoms.

Posted Jul 01, 2019

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A study published last week in the Journal of Cross-Cultural Psychology found that parents in Australia and the United States were more likely than parents in Norway and Sweden to report ADHD symptoms in their young children. The study also found that Scandinavian parents tended to "diagnose" ADHD more accurately than their counterparts in Australia and the U.S.

Mental health researchers have known for some time that ADHD (attention-deficit/hyperactivity disorder) is diagnosed more frequently in some countries than in others. The estimated global rate of ADHD is 5.3 percent of the population (MacDonald et al., 2019), but the U.S. rate is 9.4 percent (Danielson et al., 2018). The rate in Sweden is just 3.7 percent.

Although the existence of national differences is well-established, researchers aren't sure how to explain the differences. Maybe ADHD really is more common in the U.S. than in Sweden. Maybe Swedish parents, teachers, and doctors underreport the actual prevalence of the disorder. Maybe American parents, teachers, and doctors overreport. Or maybe something else is going on.

Clinical psychologist Beatriz MacDonald at the University of New Mexico assembled a team of researchers from the United States, Australia, Norway, and Sweden. They knew about previous studies showing higher-than-average rates of ADHD in Australia and the United States and lower-than-average rates in Norway and Sweden. MacDonald and her team aimed to replicate the earlier findings and, more importantly, discover the reasons for the different rates.

Before they collected any data, the team identified five possible explanations for the country differences. 

Hypothesis 1: ADHD may actually be more prevalent in some countries and less prevalent in others.

Hypothesis 2: ADHD may appear to be more or less prevalent because health care providers in different countries use different definitions and measures of ADHD.

Hypothesis 3: (This one is complicated but also clever.) ADHD may be more noticeable at an early age in those countries that teach certain academic skills (like reading) to preschoolers. (The United States is one such country; Norway and Sweden are not.) Why? Because symptoms of ADHD—not paying attention and fidgeting, for example—are less noticeable when children aren't expected to sit still and focus on their studies.

Hypothesis 4: Parents, teachers, and doctors in some countries may underreport the prevalence of ADHD. Why? Because some cultures and societies stigmatize childhood mental disorders. Consequently, parents and others are reluctant to report potential cases of ADHD.

Hypothesis 5: Parents, teachers, and doctors in some countries may overreport the prevalence of ADHD. Why? Because some cultures and societies pathologize behaviors that are part of the normal behavioral repertoire of young children. People who adopt this "cultural lens" will sometimes see ADHD when it isn't actually there.

To test these hypotheses, MacDonald and her team studied 974 children in four countries: Australia, Norway, Sweden, and the United States. Some of the children were 5 years old and in preschool. Others were 7 years old and in second grade.

To estimate the prevalence of ADHD symptoms in the children, the researchers asked their parents to complete a portion of the Disruptive Behaviors Rating Scale (DBRS), a reliable and valid measure used in many countries.

Each parent rated their child in terms of 18 different symptoms of ADHD including trouble sustaining attentiondoes not listen, easily distracted, on the go, leaves seat, and blurts out answers. Each parent rated each symptom on a 4-point scale:

0 = never or rarely
1 = sometimes
2 = often
3 = very often

To assess the validity of the parents' ratings, the researchers administered a battery of cognitive tests to the children. The tests measured verbal memory, naming speed, and visuospatial skills. According to the researchers, these cognitive tests are known to be sensitive to ADHD; children who truly suffer from ADHD perform relatively poorly on the tests.

MacDonald's team uncovered five interesting findings.

  1. The Norwegian and Swedish samples did not differ on any of the measures, so their data were combined into a single Scandinavian group.
  2. The rates of young children with ADHD (based on parents' DBRS ratings) were similar to rates reported in previous studies: 4 percent in Scandinavia, 10 percent in the United States, and 11 percent in Australia.
  3. In all four countries, boys had more symptoms—and more severe symptoms—than girls did. The difference was observed in both age groups, the 5-year-olds and the 7-year-olds.
  4. Compared to Scandinavian parents, American parents and Australian parents reported more ADHD symptoms in their children. The country differences were observed in both age groups. 
  5. The ADHD judgments of Scandinavian parents corresponded more closely with the objective measures of cognitive skills than did the ADHD judgments of parents in Australia and the United States. In other words, Scandinavian parents tended to be more accurate in their "diagnoses" of actual ADHD cases.

Given the findings from their four-country study, Dr. MacDonald and her colleagues were able to draw tentative conclusions about the hypotheses stated earlier.

  • No support for Hypothesis 2. The countries studied had different prevalence rates of ADHD, but the differences can't be explained by the use of different measuring instruments because parents in all four countries used the same instrument to measure the frequency of ADHD symptoms.
  • No support for Hypothesis 3. The prevalence of ADHD symptoms in each country was unaffected by whether children were being asked to sit still for academic lessons. In all four countries, the rates of ADHD were the same for preschoolers and second graders.
  • No support for Hypothesis 4. Parents in Norway and Sweden didn't underreport ADHD symptoms because their ratings matched the results of the cognitive tests better than the other parents' ratings did.
  • Good support for Hypothesis 5, that some countries may overreport the prevalence of ADHD. Compared to Scandinavian parents, American and Australian parents had a tendency to "see" ADHD in children that, according to cognitive tests, probably didn't have ADHD.

MacDonald and her team concluded their report with a warning: "It is possible that ADHD is being overdiagnosed in some countries, such as the United States and Australia." Given the relationship between an ADHD diagnosis, chemical treatment, and increased medical costs, parents of young children may want to think twice before boarding that particular train.

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Danielson, M., and 5 others. (2018). Prevalence of parent-reported ADHD diagnosis and associated treatment among U.S. children and adolescents, 2016. Journal of Clinical Child & Adolescent Psychology47 (2), 199-212. DOI: 10.1080/15374416.2017.1417860

MacDonald, B., and 6 others. (2019). Cross-country differences in parental reporting of symptoms of ADHD. Journal of Cross-Cultural Psychology. DOI: 10.1177/0022022119852422

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