Attention-deficit/hyperactivity disorder: seeking the right balance between over- and undertreatment

Abstract

This issue of European Child and Adolescent Psychiatry contains an article that addresses functional impairments associated with subthreshold attention-deficit/hyperactivity disorder (ADHD) [2]. In a Korean nationwide community sample of 921 children, aged 8–11 years, the authors report that children with subthreshold ADHD were found to experience significant functional impairments, i.e., poorer behavioral and emotional control and worse academic performance compared to control children. Subthreshold ADHD was defined by the presence of at least three but no more than five inattentive or hyperactive/impulsive symptoms. However, whereas the diagnostic threshold (C6/9) for the DSM-IV symptoms represents a clear-cut operationalization for a diagnosis of ADHD, this disregards the fact that for the affected individuals and their parents the relevance of each symptom is likely to be different; for the diagnostic assessment as defined by the DSM-IV the symptoms are merely being counted, without taking the severity of each symptom into account. Furthermore, the subjective and objective impairment due to ADHD symptoms can in theory be greater in a child who fulfills only five symptoms in comparison to a child with six or more symptoms. These considerations illustrate how difficult it is to meaningfully operationalize thresholds for a spectrum disorder such as ADHD. It is certainly an interesting approach to illustrate impairments in a subthreshold version of a disorder that has received so much coverage by media, politicians, and government due to concerns about overdiagnosis and overtreatment with medication, in particular psychostimulants. The article of Hong et al. [2] in this issue illustrates that there is not a simple clear-cut boundary between ADHD and ‘normality’, which we should be well-aware of, when considering concerns of possible overdiagnosis. What is true, is that over the past decade, there has been a rapid and tremendous increase in the diagnosis of ADHD and in the use of medication treatments for ADHD within many European countries, in particular methylphenidate. This increase in the use of medication may be explained by several factors. First, better recognition and diagnosing of ADHD, in particular among girls. Second, the observation that children with ADHD receive the medication at a younger age than before. Third, it is now commonplace to receive the medication for many years, often during adolescent years and more and more into adulthood [4]. It is unclear, however, whether also children are being diagnosed and/or medicated in spite of falling below the diagnostic threshold set by DSM-IV (C6/9 criteria for either inattention or hyperactivity/impulsivity, or both) or failing to meet other aspects of the DSM-IV algorithm. A second issue is that the increased and longer use of methylphenidate contrasts with the lack of long-term data on effectiveness. In fact, for example, the official Dutch multidisciplinary guidelines explicitly state that there is currently only evidence for the long-term effectiveness of methylphenidate for treatment duration between 3 months and 2 years. Much of our knowledge about treatment periods of longer than a year comes from following up a single study, the Multimodal Treatment of ADHD study (MTA) [12]. Earlier reports from the MTA study found that children taking stimulants alone or combined with behavioral treatment did better in the first year than children who got no special care or who got behavioral treatment alone. Later long-term reports from the MTA study tracked 485 P. J. Hoekstra (&) A. Dietrich Department of Psychiatry, University of Groningen, University Medical Center Groningen, Hanzeplein 1-XA10, 9713 GZ Groningen, The Netherlands e-mail: p.hoekstra@accare.nl