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Commentary Neuroscience

ADHD: Over Diagnosed or Loosely Defined?

Accusations of ADHD’s overdiagnosis have been on a rise in recent years, as have diagnosed cases of ADHD. In 1997, the parent-reported percent of children with an ADHD diagnosis in a National Health Institute survey was just under 6%. Ten years later, this figure had risen to 10% [2].

Introduction

Attention deficit hyperactivity disorder (ADHD) is generally manifested through difficulty focusing. The disorder’s diagnostic criteria, as described in the latest edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), includes a persistent pattern of inattention and/or hyperactivity-impulsivity that interferes with functioning or development, the presence of several inattentive or hyperactive-impulsive symptoms prior to the age of twelve and in two or more settings, clear evidence the symptoms interfere with social, academic, or occupational functioning, and the precedent that the symptoms cannot be explained by another mental disorder. The DSM-5 also provides examples of behaviors that may be indicative of ADHD, including frequent fidgeting, excessive talking, difficulty waiting for a turn, an inability to play quietly, and frequent interruption of others [1]. Many remark that these symptoms are merely traits of being a child and are not signs of a disorder. Accusations of ADHD’s overdiagnosis have been on a rise in recent years, as have diagnosed cases of ADHD. In 1997, the parent-reported percent of children with an ADHD diagnosis in a National Health Institute survey was just under 6%. Ten years later, this figure had risen to 10% [2]. Similar results have fueled a growing debate as to whether these diagnoses are the result of a widening definition of the disorder or a true increase in those afflicted. 

Identifying Over Diagnosis

The commonly-held notion that ADHD is loosely and  inaccurately diagnosed stems from an assumption that many diagnoses are falsely positive. For ADHD to be justifiably labeled as overdiagnosed, there must be evidence that the total number of false positive diagnoses significantly outweighs the number of falsely negative diagnoses [3]. Such evidence has not yet been discovered, thereby establishing the ability to recognize the factors at play in a potential false positive ADHD diagnosis as vital in gaining insight to the overdiagnosis assumption. 

Potential Components of Misdiagnosis

The relative age of schoolchildren is a common explanation for ADHD misdiagnosis. Numerous studies have found that children who are relatively younger than their classmates are at an increased risk of ADHD diagnosis. In a study conducted within a school whose school-age cutoff is December 31, results revealed that boys born in December were 30% more likely to be diagnosed and 41% more likely to be treated for ADHD than their January-born peers. Girls born in December were 70% more likely to be diagnosed and 77% more likely to be treated for ADHD than those born in January [4]. These findings suggest that diagnostic measures have failed to account for the relative developmental immaturity of young children, leaving unnecessary room for subjectivity in diagnosis. 

Early diagnosis provides another point of concern in the misdiagnosis of ADHD, given that most ADHD research has been conducted on older, school-age children, rather than younger preschoolers [4]. Research as to the manifestations of ADHD at such a young age has been limited. Current diagnostic measures are geared toward older children and may lead to false positive diagnoses, especially considering the prevalence of inattention, impulsivity, and hyperactivity at that developmental age [5]. 

The argument of diagnostic inaccuracy has been substantiated in a number of studies, such as a 1993 study that evaluated 92 children previously referred to a specialized ADHD clinic. Of the referrals, only 22% received a primary diagnosis of ADHD and only 37% were given a secondary diagnosis [3]. Variability in assessment among providers may be to blame for these diagnostic inaccuracies that may contribute to an increase in false positive diagnoses. 

Potential gender differences in the manifestations of ADHD may be at blame for deflated diagnoses in girls. It has been hypothesized that boys tend to exhibit the prototypical characteristics of ADHD through disruptive and hyperactive behaviors. Girls, however, may exhibit less externalized and disruptive behavior that had become characteristic of ADHD and increased intellectual impairment [4]. A potential inability to distinguish between different manifestations of the disorder suggests further inaccuracy in the diagnostic criteria. 

Conclusion

It appears to be overwhelmingly evident that ADHD is often misdiagnosed. Fallacies in the diagnostic criteria may be to blame for an inflated number of diagnoses in preschool-age children and developmentally immature children, as well as a deflated number of diagnoses in girls. Although such diagnostic concerns have been supported by a number of studies, sufficient evidence for systematic overdiagnosis remains lacking. Due to the variability in assessment techniques by provider, prevalence rates of ADHD are unreliable and cannot be used to prove that the number of false positive diagnoses drastically outweigh the number of false positive diagnoses. Despite this, the popular idea that ADHD is widely misdiagnosed remains intact, and likely will remain as such. It is important to remember that such claims are generally based on unreliable data and should be deemed untrustworthy by association. 

Alaina Buerger, Youth Medical Journal 2022

References

[1] Reynolds, Cecil and Kamphus, Randy. “Attention-Deficit/Hyperactivity Disorder (ADHD).” DSM-5 Diagnostic Criteria, Pearson, 2013, http://images.pear sonclinical.com/images /assets/basc -3/basc3resources/DSM5_DiagnosticCriteria_ADHD.pdf

[2] “Attention-Deficit/Hyperactivity Disorder (ADHD).” Centers for Disease Control and Prevention, 23 September 2021, https://www.cdc.gov/ncbddd/adhd/timeline.html

[3] Scuitto, Mark. “Evaluating the Evidence For and Against the Overdiagnosis of ADHD.” Journal of Attention Disorders, Sage Publications, September 2007, pp. 106-113, https://t heunbrokenwindow.com/wp-content/uploads/2017/10/ADHD-Overdiagnoses.pdf

[4] Ford-Jones, Polly Christine. “Misdiagnosis of attention deficit hyperactivity disorder: ‘Normal behaviour’ and relative maturity.” Paediatrics & child health vol. 20,4 (2015): 200-2. doi:10.1093/pch/20.4.200

[5] Tandon, Mini et al. “Attention-deficit/hyperactivity disorder in preschool children: an investigation of validation based on visual attention performance.” Journal of child and adolescent psychopharmacology vol. 19,2 (2009): 137-46. doi:10.1089/cap.2008.048 

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