The difficulty of identifying ADHD in children
Diagnosing ADHD, or attention deficit hyperactivity disorder, is intrinsically problematic.
The symptoms—distractibility, impulsivity, and hyperactivity—are consistent with the normal behavior of young children.
So when kids are diagnosed, the implication is that they are more distractible, impulsive, or hyperactive than they should be for their age.
But where do we draw the line between developmentally-normal behavior and medical disorder?
That's a crucial question because diagnosis rates among very young children are on the rise, and many kids are being medicated.
According to historical health data collected in the United States, the percentage of 2-to-5-year-olds diagnosed with ADHD increased by 50% between 2008 and 2012 (Danielson et al 2017).
And a study by the U.S. Center for Disease Control indicates that children diagnosed in this age group are more likely to receive prescription medication (Visser et al 2016).
Should we be concerned about these trends? I think so, and public health experts agree.
In a recent review of published studies, Luis Kazda and her colleagues (2021) report evidence that ADHD is being over-diagnosed and over-treated.
In addition, they note that medication comes with side effects. And being stuck with a label of ADHD? That can sometimes have negative psychological consequences.
So for kids who are wrongly diagnosed -- or who suffer from only mild ADHD symptoms -- diagnosis and treatment might do more harm that good (Kazda et al 2021).
Here I review current ideas about ADHD in children, including reasons for doubt and caution.
It's not a comprehensive account of ADHD, and it's not meant to deny that some kids suffer from important attention or hyperactivity problems. If you think your child might have ADHD, you should discuss your concerns with a physician.
But the following account provides an overview of the reasons why parents should exercise a healthy skepticism when it comes to diagnosing and medicating children for ADHD. Particularly when children are young.
Attention deficit disorder, or ADHD, has been defined as "the co-existence of attentional problems and hyperactivity."
According to the American Academy of Child Adolescent Psychiatry (AACAP), this means a child who
In addition, the child must be symptomatic for at least 6 months, and the symptoms must interfere with the child's ability to function in at least two areas of life:
In an article online, the American Academy of Child Adolescent Psychiatry also specifies that the symptoms should emerge before the age of 7 years.
It's possible, but it's problematic. Why? Because young children are naturally squirmy, impulsive, and prone to emotional outbursts. They have shorter attention spans. They find it difficult to follow directions and stay on task.
In other words, it's normal for young children to behave in ways that mimic ADHD. These are age-typical behaviors. If we're patient, we may find that young children will grow out of their ADHD "symptoms."
To see what I mean, consider the results of a study conducted in Sweden. Researchers screened 422 first graders for signs of ADHD by asking parents and teachers to answer a standard, ten-point questionnaire (the "Conners 10-item scale").
Three years later, they checked on the children's progress.
Did the early screening predict which kids would receive a formal diagnosis of ADHD in the fourth grade?
It did, but with a big margin of error. The very best predictor--which was a combination of high scores from both parents and teachers--had a positive predictive value of 50%, meaning that only half the children who screened positive for ADHD in the first grade ended up with a formal diagnosis in the fourth grade (Holmberg et al 2013).
Western organizations, like the American Academy of Pediatrics, have suggested that children can be diagnosed as early as 4.
But it appears that some kids are getting tested and diagnosed at even younger ages. Based on a recent survey of more than 45,000 kids in the United States, approximately 2.4% of children between the ages of 2 and 5 have been diagnosed with ADHD (Danielson et al 2018).
I'm not a psychiatrist, and I'm not saying we should dismiss all early diagnoses as erroneous. But I think we need to consider the possibility that cultural factors are playing an important role in the diagnosis of ADHD.
In places like the United States -- where ADHD diagnoses are on the rise -- young children may face special challenges.
They attend daycare or preschools where adults are continually telling them where to go and how to behave.
They attend kindergarten classes that are more demanding, more academic than classes were in previous generations.
In effect, it seems to me that many young children are being asked to behave like little office-workers. Sit at your desk. Pay attention to my instructions. Stay on task. Don't talk out of turn.
Some kids might thrive in these environments. They are more developmentally-advanced than their peers, and they find it relatively easy to comply.
But other kids may struggle. Not because they have ADHD, but because they are developmentally-normal individuals who aren't yet equipped for the mature demands adults are placing on them.
We're simply asking too much. Kids fail to meet our standards, and we perceive that the children suffer from behavior problems -- and, possibly -- ADHD.
What makes me think this is going on?
One line of evidence is anthropological.
To put the "little office-worker" demands into perspective, consider how children are treated in other cultures.
Around the world, people living in traditional societies show remarkable agreement. They don't expect kids to show much self-discipline until they are 6 or 7 years old.
For instance, in a famous study, psychologist Barbara Rogoff and her colleagues reviewed attitudes about children in 50 different traditional cultures -- including societies where people make a living by foraging, herding, and farming (Rogoff et al 1975).
The researchers asked all sorts of questions. At what age do people think kids are capable of making rational decisions and showing common sense? When should adults expect kids to follow rules? At what age should adults make an earnest attempt to teach kids manners and etiquette?
The answers were pretty consistent.
In most places, people didn't expect children to play rule-based games until they were at least 6 years old.
They didn't expect kids to show common sense or rationality until they were at least 6.
They didn't make a special effort to teach children social etiquette until kids were around 7 years old.
So we see a different set of expectations here, relative to the "little office-worker" expectations that some preschoolers may encounter in places like the United States.
A 4- or 5-year-old who struggles in a United States preschool classroom might have no difficulty meeting the standards of a traditional, pre-industrial society.
In the United States, people wonder if the child has ADHD. In a traditional, pre-industrial culture, people don't perceive anything anomalous or pathological. They view the child's behavior as developmentally-normal.
The difference is cultural.
The first look at a troubling pattern
Todd Elder of Michigan State University wanted to know if children are being misdiagnosed with ADHD because they show normal levels of distraction and hyperactivity for their age.
So he trawled through some old data: a large, longitudinal study of kindergartners conducted by the U.S. National Center for Education Statistics (Elder 2010). And he took a look at two groups of kindergartners:
Elder's reasoning went like this. If kindergartners are getting diagnosed with ADHD because they have a real psychological disorder—and not because they show developmentally-normal signs of immaturity—then there should be no correlation between a child’s age and his or her diagnosis.
In other words, the youngest kindergartners should be no more likely than the oldest kindergartners to get diagnosed with ADHD.
But that's not what he found. On the contrary, the youngest kindergartners were 60% more likely to be diagnosed with ADHD than were the oldest kindergartners.
And being labeled with ADHD seemed to have lasting consequences. When Elder examined older kids, he found that the youngest students in the fifth and eighth grades were twice as likely to be medicated for ADHD.
Based on his analysis, Elder estimates that as many as 20% of the 4.5 million American kids identified with ADHD have been misdiagnosed (Elder 2010).
International studies report a similar trend
Elder's results have been replicated by researchers in other countries.
For instance, in Taiwan, investigators found that boys and girls born in August (the last month before the official school cutoff) had 63% higher odds of being diagnosed than kids born in September. Their odds of being medicated were 76% higher (Chen et al 2016).
In Sweden, six-year-old kids born in the two month interval before the cutoff had 80% higher odds of being prescribed ADHD medication compared with kids born in the two month interval after (Halldner et al 2014).
The relative age effect has also been documented in Canada (Morrow et al 2012) and Israel (Hoshen et al 2016).
And -- overall --there's reason to think that many kids are being wrongly diagnosed.
In a recent review of the scientific literature, Luise Kazda and colleagues analyzed 334 published studies of ADHD in children and adolescents. The researchers concluded that there is convincing evidence that ADHD is overdiagnosed (Kazda et al 2021).
In that Swedish study I just mentioned, the researchers noticed an interesting pattern: The youngest kids in the classroom didn't seem to have more trouble at home. Parental reports of ADHD-like symptoms were unrelated to a child's relative age.
So pressure to diagnose kids with ADHD was mostly coming from school. What can we do to alleviate that pressure?
One approach is to delay school entry for kids who aren't ready. As the Swedish researchers note:
"...[F]lexibility regarding age at school start according to individual maturity could reduce developmentally inappropriate demands on children and improve the precision of ADHD diagnostic practice and pharmacological treatment."
This approach is common in Denmark, which may explain why researchers in that country have found almost no relative age effect on medication use Pottegård et al 2014).
But another alternative is to adjust our expectations about what kids can do.
Can we redesign school in ways that acknowledge individual differences in maturity level? Or is would this be too costly and difficult to manage? These are important questions to research and debate.
It's true that ADHD is highly heritable.
We know this from twin studies that compare identical twins (who share nearly 100% of their genetic polymorphisms) with fraternal twins (who share, on average, only 50% of their genetic polymorphisms).
Identical twins are much more likely than fraternal twins to share a diagnosis of ADHD (Faraone and Mick 2010).
Presumably, that's because there are genes that play a role in the development of ADHD. These genes may code for traits that alter levels of neurotransmitters in the brain.
Researchers have developed medications that target specific
neurotransmitters, and some of these medications have high success rates in helping ADHD patients control their symptoms, at least in the short-term (Stuhec et al 2015).
But that doesn't mean that everybody diagnosed with ADHD has a disorder. And it doesn't mean that everybody benefits from medication.
The observation that kids with ADHD share certain genes—or even certain neurotransmitter profiles—is interesting but not unusual. We can say the same thing about kids who are shy, or perennially cheerful, or more aggressive than average (DiLalla 2002).
People are different, in part, because they carry different genes and develop different brain chemistries. That doesn't imply that all differences are pathological. Nor does it particularly matter why individual differences evolved—not when we're trying to decide if Marcus or Sylvia needs to be medicated.
Some researchers speculate that evolution has favored certain "ADHD genotypes." For instance, one theory posits that ancient social groups would have benefited by having a few ADHD-types as members. The more hyperactive, distractible people would have been the trailblazers—the people who sometimes discovered new survival tactics (Williams and Taylor 2006).
It's an interesting theory. But it doesn't—by itself—tell us if a child's behavior is pathological or worthy of medication.
Whether or not we regard ADHD as a "real" medical condition depends on other considerations, including our cultural assumptions. And even if we make the judgement that a child has a medical condition, we must weigh the costs of a treatment (like the risks of side-effects for taking a particular medication) against the apparent benefits.
For example, we might judge that a child has insomnia, but that diagnosis doesn't imply that medication is the best response. After examining the best available evidence, we may determine that the costs of medication (the problems and risks posed by side effects) outweigh any apparent benefits.
The same is true of an ADHD diagnosis. The most frequently prescribed drugs for ADHD have been linked with sleep problems, poor appetite, and abdominal pain (Storebo et al 2015; Punja et al 2016). For some people, such risks may make drug use undesirable.
Moreover, it's important to understand that these stimulants are classified as schedule II drugs by the FDA, indicating that they have a high potential for abuse and severe dependence. When abused or taken in high doses, the drugs may cause psychosis (Lakhan and Kirchgessner 2012).
Finally, we should be concerned about what we don't know. As the authors of leading meta-analyses have noted, virtually all of our knowledge of side effects is based on "very low quality evidence" (Storebo et al 2015; Punja et al 2016). Studies are poorly-controlled, and typically track children only for short intervals.
This conclusion about the state of research on ADHD-prescribed amphetamines summarizes the nature of the problem (Punja et al 2016):
"Most of the included studies were at high risk of bias and the overall quality of the evidence ranged from low to very low on most outcomes. Although amphetamines seem efficacious at reducing the core symptoms of ADHD in the short term, they were associated with a number of adverse events...Future trials should be longer in duration (i.e., more than 12 months), include more psychosocial outcomes (e.g. quality of life and parent stress), and be transparently reported."
Are some kids just "overtired?"
Young children aren't the only people who have trouble holding still and controlling their impulses.
Experimental studies show that elementary school kids become more moody when they get less sleep (El Sheikh and Buckhalt 2005). Even adults become more distracted and emotional when they are sleep-deprived (Yu et al 2007). Are some kids diagnosed with ADHD really just suffering from sleeplessness?
It's plausible. Studies confirm that ADHD-diagnosed kids are more likely to suffer from sleep
disorders (Shur-Fen Gau S 2006; Chiang et al 2010; Hansen et al 2013;
Moreau et al 2013). And in one study, kids who were treated for specific
sleep problems, like obstructive sleep apnea, experienced improvements in their ADHD symptoms (Huang et al 2007). Could your child's troubles stem from poor sleep? It's worth investigating.
Other conditions that can cause symptoms of ADHD in children include
possible that some cases of ADHD in children are caused by poor working memory.
A child with low-capacity working memory has trouble keeping complex directions and goals in mind while she works. As a result, she may appear distracted or disobedient.
You may have heard the claim that ADHD doesn't exist. That it's a "lie" being perpetrated by special interests, like drug companies. Is this a valid point of view?
As with most claims, it depends on your specific meaning. It's not a lie that some people are more distracted, impulsive, or hyperactive than others. It's not a lie that some of these people suffer substantial impairments in their daily lives. And it's clear that attention deficits and hyperactivity -- like other traits -- are related to differences in brain chemistry.
So there's no question that millions of people fit the medical definition, and many of these folks have serious problems. What's less clear is causation. Do people diagnosed with ADHD represent a group affected by the same underlying causal mechanisms? Or is the population of ADHD patients a mixed bag? A collection of people who experience similar behavior problems for a variety of different reasons?
If your definition of ADHD depends on identifying a single, underlying cause, then there is reason to doubt the existence of ADHD. The science isn't there, at least not yet. But if you take a less restrictive definition, the label captures a real phenomenon: People struggling with behavioral tendencies that put them at a disadvantage in the current cultural environment.
For more reading on related topics related to ADHD in children, check out these research-based tips for helping children develop self-control and my articles about the psychological benefits of play and working memory in children.
In addition, for more cross-cultural insights about child behavior problems, check out my article, "Why kids rebel (and what we can do to encourage cooperation)."
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Content of "ADHD in children" last modified 4/2021
Portions of this text are derived from an earlier version of this article.
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