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 a child is diagnosed, the implication is that he is more distractible, impulsive, or hyperactive than he should be for his age.
But where do we draw the line between developmentally normal behavior and medical disorder?
Here I review current ideas about ADHD in children--including reasons for doubt.
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 of young children should exercise a healthy skepticism before accepting a diagnosis of ADHD. I raise these points:
• The official definition of ADHD in children is based on subjective criteria. To get diagnosed with ADHD, a child's symptoms should be bothersome--so much so that she has trouble functioning at school or in other social settings. But who sets the standards that kids must meet to be considered normal?
• Expectations about kids have probably changed over the decades. In Britain, all kids begin formal schooling at the age of 4. In the United States, kindergarten is becoming more academic. But in many traditional cultures, people don't expect much self-discipline from children until they are 6 or 7.
• Many kids may be misdiagnosed. As a recent study suggests, some kids are being diagnosed with ADHD because they are young, not because their behavior falls outside the range of normal development.
• Biomarkers don't prove that a person needs drugs. Kids diagnosed with ADHD are more likely to carry certain genes and exhibit certain brain chemistry profiles. But we can probably say the same about kids who are shy, or aggressive, or perennially cheerful. Genes and neurotransmitters influence all sorts of behavior. That--by itself--doesn’t make behavior pathological or worthy of medication.
• ADHD isn't the only cause of distractibility or hyperactivity. ADHD-like symptoms may be caused by a variety of conditions, including sleep disorders, anxiety, and poor working memory skills.
1. Defining ADHD in children
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 seems to be in constant motion—squirming and fidgeting and moving around the room. It also may be impulsive behavior, blurting out comments without thinking them through first. Unrestrained displays of emotion.
And it may mean that the child quickly becomes bored unless it’s an activity he particularly enjoys.
If you think ADHD symptoms sound like the description of a normally-developing preschooler, you’re right.
Virtually everybody shows these “symptoms of ADHD” when they are two, three, or four years old.
And different kids develop at different rates. Some take a little longer to focus their attention and restrain their impulses.
On average, though, most kids seem to settle down between the ages of 5 and 7. And this age range is recognized worldwide. It’s called the “5-to-7” transition. The period during which young children begin to show more “executive control,” when they become better at planning ahead, thinking abstractly, focusing attention, and inhibiting inappropriate behavior.
Along these lines, it's interesting to reflect on the results of a recent 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 kids' progress.
Did the early screening predict which children 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 first graders who screened positive ended up with a formal diagnosis in the fourth grade (Holmberg et al 2013).
Around the world, societies show remarkable agreement. Kids aren’t expected to show much self-discipline until they reach the 5-to-7 transition.
In a famous study, psychologist Barbara Rogoff and her colleagues reviewed 50 different cultures to discover when ordinary people think kids are capable of self-control and ready to meet responsibilities (Rogoff et al 1975).
The researchers considered a wide array of criteria, including these:
• The age at which people think kids are capable of making rational decisions and showing common sense
• The age at which people make a special effort to teach kids manners, etiquette, morals, and social taboos
• The age at which kids are included in games that require adherence to the rules.
• The age at which people expect kids to learn the practical and technical skills modeled by adults
The results suggest that regular people don’t demand much executive control from young children.
The majority of societies surveyed didn’t expect to observe common sense and rationality before the age of 6.
In most places, kids weren’t even asked to play rule-based games until they were at least 6.
And the most common age at which people began making a special effort to teach kids social rules was 7 years.
So it seems awkward to try to diagnose a child with ADHD while he’s still in preschool. Or even first grade. Behavior that is entirely normal and age-appropriate might get labeled as ADHD.
But unfortunately, it’s not unusual for kids to get diagnosed at an early age.
Indeed, according to the AACAP, a child shouldn’t be diagnosed with ADHD unless his symptoms emerge before the age of 7.
To be fair, those aren’t the only criteria. 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:
• at home,
• in the classroom,
• on the playground, and
• in other social settings
This idea of testing the child’s ability to function seems reasonable enough. But who sets the standards?
If we ask a kindergartener to sit still for 20 minutes, or to pay attention to what he regards as a boring lecture, he might have trouble. But is this because he’s got a psychological disorder, or because we’re asking him to conform to standards of maturity that are unrealistically high?
Todd Elder of Michigan State University wanted to know if kids are being misdiagnosed with ADHD because they show normal levels of distractibility and hyperactivity for their age.
So he trawled through some old data--
a longitudinal study of kindergarteners conducted by the U.S. National Center for Education Statistics (Elder 2010).
Elder took a look at two groups of kindergarteners:
• the youngest kids, who were born in the month prior to their state’s cutoff date for kindergarten, and
• the oldest kids, who were born in the month immediately after the cutoff
His reasoning went like this: If kindergarteners 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 her diagnosis.
In other words, the youngest kindergarteners should be no more likely than the oldest kindergarteners to get diagnosed with ADHD.
But that’s not what he found.
The youngest kindergarteners were 60% more likely to be diagnosed with ADHD than were the oldest kindergarteners. 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).
Elder's results have been replicated by researchers studying school children in British Columbia (Morrow et al 2012). In this Canadian study, boys born in December were 30% more likely to receive an ADHD diagnosis than were boys born in January. For girls, the risk of diagnosis was 70% greater.
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 these medications have helped some ADHD patients.
But that doesn’t mean that everybody diagnosed with ADHD really 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 Mario 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).
Again, that’s an interesting theory. But it doesn’t—by itself—tell us if a child’s behavior is pathological and worthy of medication.
Whether or not we regard ADHD as a "real" medical condition depends on our cultural assumptions.
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?
Studies show that ADHD 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 when ADHD kids have been treated for specific sleep problems, like obstructive sleep apnea, their ADHD symptoms have improved (Huang et al 2007).
This doesn’t mean that the sleep problems caused ADHD symptoms. It’s possible that the ADHD symptoms caused the sleep problems. But it’s worth further investigation. Would a child’s ADHD symptoms improve if he got more sleep?
Other explanations your doctor should rule out
Other conditions that can cause symptoms of ADHD in children include
• Thyroid problems
• Clinical anxiety or depression
• Emotional traumas and sudden life changes
• Lead poisoning
• Undetected seizures
possible that some cases of ADHD in children are really 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.
7. Denying that ADHD exists at all
You may have heard the claim that ADHD doesn't exist. That it's a "lie" being perpetrated by drug companies.
Is this a valid point of view? The trouble is that the claims are vague. It's not a lie that some kids are more distracted, impulsive, or hyperactive than others. It's not a lie that some of these kids suffer substantial impairments in their daily lives. And it's clear that attention problems and hyperactivity -- like other traits -- are related to differences in brain chemistry.
But, as I note above, that doesn't tell us if the traits are intrinsically pathological. Links with genes and neurotransmitters don't prove that a trait a "real" medical problem.
Think of male pattern baldness. Some men have a genetic tendency to become bald as they age. But that doesn't mean that baldness is a medical problem.
Different people have different traits--like a tendency to become bald, or a tendency to be more impulsive. Whether or not we perceive these traits as medical problems depends on our cultural context.
And, as I've argued in this article, the cultural context of ADHD seems particularly important.
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
working memory in children.
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Content of "ADHD in children" last modified 3/13