Diagnosing ADHD: personality quirks or psychiatric disorder?

In a humorous article called “Pathology in the Hundred Acre Wood,” published in the Canadian Medical Association Journal in 2000, Sara Shea and colleagues sarcastically diagnosed and suggested medical treatment for the popular Winnie the Pooh characters. Piglet was diagnosed with generalized anxiety disorder, Eeyore with depression, and the lovable but dull-headed Pooh was diagnosed with attention deficit hyperactivity disorder, inattentive subtype.
Surprisingly, an unusually large number of responses to the article poured in from around the country—some missing the sarcasm and outraged that funding for research was being spent inappropriately, and some upset that the authors were poking fun at serious psychiatric disorders. The article, and the large mix of opinionated responses to it, highlights the rifts in opinion concerning diagnosing and prescribing medication for what some see as merely personality characteristics.
Among these psychiatric disorders, ADHD is probably the most entrenched in conflicting public, medical, and personal opinions about diagnosis and necessity of medical treatment. Some mothers become irrationally convinced that their child has ADHD, and others refuse to believe that having a high-octane, impulsive lifestyle should be classified as a psychiatric disorder. So how do you know if you or a close family member actually has ADHD, and whether or not you should treat it with serious psychoactive drugs? The answer, unfortunately, is iffy at best.
Attention Deficit Hyperactivity Disorder (ADHD) has, in the past decade, gripped the curiosity of our society for its social, political, and scientific complexity. About 3-9% of children around the world have ADHD, and as many as half of these kids will continue to exhibit symptoms into adulthood. The core cognitive deficits of the disorder include impulsivity, hyperactivity, and difficulty sustaining attention.
Despite the numerous and detailed genetic, anatomical, and behavioral data that have begun to characterize ADHD patients, it is still very difficult to confidently diagnose a child or adult with the disorder. This is partly due to the fact that the patient or patient’s parents provide most of the observational evidence for diagnosis, and partly because diagnosing it involves analyzing complex cognitive functions. Adding to the confusion is the fact that all ADHD symptoms occur normally in most individuals, but with much less severity and with no debilitating impact on daily living. In fact, in any given population there is a range of individuals exhibiting anywhere from no ADHD symptoms to severely displaying almost all of the symptoms. However, research in the fields of neuroscience, genetics, and neuroimaging could allow for more concrete diagnostic criteria as well as unique treatments in the future.
One approach in ADHD research is to use large-scale cognitive evaluations, such as observing patients or animal models doing tasks that require attention. This research is able to pinpoint specific cognitive deficits associated with the disorder, and can lead to new diagnostic criteria and test the effectiveness of new medications. Another approach is to attempt to discover underlying molecular mechanisms causing ADHD by looking at brain anatomy and physiology associated with the disorder’s symptoms. Both lines of research uncover valuable information about the disorder that can help doctors and patients diagnose and treat ADHD more accurately.
One of the most prominent biological characteristics of the disorder is a deficiency in the neurotransmitters dopamine and norepinephrine. Lower concentrations of these chemicals in the prefrontal cortex (involved in planning future actions) and basal ganglia (involved in coordinating complex motor activity), generally affect our ability to select, initiate, and complete complex tasks. Methylphenidate, commonly known as Ritalin, is a common stimulant used to treat ADHD symptoms that acts on dopamine transporters in the brain to counteract these chemical imbalances. Several genes have also been implicated in the disorder, and when they are present an individual has about a 75% chance of having the disorder.
Another interesting association with ADHD that has emerged is recurrent tonsillitis and snoring. It is believed that partially blocking a developing child’s airways during sleep, and thus desaturating the brain of oxygen, can lead to cell death in specific areas of the brain also involved in the development of ADHD. Cell death in these areas can actually lead to ADHD symptoms, and over half of children with ADHD also have disrupted breathing patterns during sleep.
On the more cognitive end of the spectrum, researchers are trying to understand the overall cognitive deficits in patients with ADHD. Although several theories have been brought up over the past decades, the most likely idea is that patients display two large psychological deficits: they are not able to inhibit impulses or random thoughts (inhibitions dysfunction), and they have trouble waiting for the completion of a task or event (delay aversion). As enticingly self-sufficient as these explanations seem, there has been no convincing research done that can link these psychological theories to the molecular data brought up by neuroscientists. Yet that hasn’t stopped some from finding a few practical, if bazaar, applications of our psychological understanding of ADHD.
UCLA Psychology professor Eran Zaidel and colleagues have discovered a unique way to treat ADHD symptoms. These researchers attached electrodes to individuals at rest, and when specific non-ADHD type brain activity occurred a computer simulated car would be propelled around a racetrack. By simply changing their thoughts haphazardly until the car began to move faster on the screen, individuals with ADHD were successfully able to at least partially alleviate their symptoms. Although this technique requires a lot of repetition to show results, it’s hard not to imagine an exciting at-home video game that interactively uses your brain activity in order to treat your ADHD symptoms.
Despite the quickly growing knowledge base for ADHD, there is still no concrete, underlying explanation connecting the psychological symptoms, brain anatomy, and physiology associated with it. Even without a clear-cut, self-explanatory model of ADHD, it is nonetheless obvious that the disorder exists and can seriously interfere with patients’ ability to perform daily life-tasks. Yet patients can show a vast range in severity of symptoms, and it is still very difficult to decide which, if any, medical treatments should be taken. At the end of the day, the lack of concrete evidence available to patients leaves them, or their parents, with the responsibility of deciding whether medical treatment is the right choice. On the whole ADHD is under-diagnosed, with only a fraction of people with the disorder seeking treatment. It is also reported that many people without ADHD are being prescribed stimulant medications. Clearly there is a significant problem facing our society as to who should and shouldn’t be taking serious psychoactive drugs.
As researchers continue to unearth stubborn details, it will become easier and easier to not only diagnose but effectively treat the often debilitating symptoms of ADHD. More people who aren’t getting treatment for their ADHD symptoms will get to, and fewer and fewer experimental but healthy college kids will be able to get their hands on stimulant drugs.

~Nate Jacobs


References:

1. Sarah E. Shea, Kevin Gordon, Ann Hawkins, Janet Kawchuk, Donna Smith (2000)
“Pathology in the Hundred Acre Wood: a neurodevelopmental perspective on A.A. Milne." CMAJ. 163 (12): 1557
2. Polanczyk G, de Lima MS, Horta BL, Biederman J, Rohde LA. (2007) “The worldwide prevalence of ADHD: a systematic review and metaregression analysis.” American J of Psychiatry. 164(6): 942-8.
3. Greydanus, DE, Greydanus, HD, Pratt, and Dilip R. Patel. (2000) “Attention Deficit Hyperactivity Disorder Across the Lifespan: The Child, Adolescent, and Adult.”

4. DM. Golan N, Shahar E, Ravid S, Pillar G. (2004) “Sleep disorders and daytime sleepiness in children with attention-deficit/hyperactive disorder.” Sleep. 15;27(2):261-6.
5. Sonuga-Barke, Edmund J.S. (2002) “Psychological heterogeneity in AD/HD: A dual pathway model of behaviour and cognition.” Behavioural Brain Research. 130(1-2): 29-36
6. Hill, Zaidel, et al. Unpublished.