Faced with hard questions, notes psychologist and Nobel laureate Daniel Kahneman, people will frequently seek to answer easier ones instead. The controversies over attention-deficit/hyperactivity disorder (ADHD) and stimulants are a good example. What does the massive increase in ADHD diagnoses and stimulant use over the past twenty years say, if anything, about profound changes in childhood, mental health diagnoses and treatment, education policies, economic conditions, government regulations, health insurance, pharmaceutical companies, family composition, health professionals, and other environmental aspects? What factors have driven this increase, and how do they interact? Such questions are very complicated, so we usually get a watered-down version of them in the popular press: Why is ADHD overdiagnosed and stimulants overused? Who is to blame for this abuse? What do these phenomena say about America and its future? The “answers” that follow are, as one would expect, as simplistic and unsatisfactory as the questions that trigger them. What we badly need are much more nuanced, analytical, comprehensive, and research-informed contributions like Stephen P. Hinshaw and Richard M. Scheffler's excellent The ADHD Explosion. Their new book is (or soon will be) required reading for parents, teachers, clinicians, scholars, and policy makers interested in mental disorders, generally, and ADHD and stimulant pharmaceuticals, in particular.The ADHD Explosion begins with the sobering observation that ADHD is the most common childhood behavioral health problem, with one in nine children and adolescents in the United States having been diagnosed. As a consequence, stimulants are the number one medication class for children and adolescents, and their rates of prescription have been climbing ever faster for adolescents and adults. For perspective, in 1990 an ADHD diagnosis had been made in approximately 4 percent of school-age children with roughly six hundred thousand youth using stimulant medications (Safer, Zito, and Fine 1996). By 2012, around 11 percent of all school-age children were diagnosed, representing about 6.4 million youth in the United States, with roughly 3.5 million school-age children using stimulant medications (CDC 2014a, 2014b). For boys, Hinshaw and Scheffler find, the overall rate of diagnosis of ADHD “is around 15% for males, between one in seven and one in six. Moreover, for boys of high school age, nearly one in five (19%) has received an ADHD diagnosis at some point in his life” (xxvi). These figures will likely rise even higher in the near future. Because of several new developments — such as the Affordable Care Act's provisions for greater access to health care, the loss of patent exclusivity on long-acting stimulants that will substantially reduce prices for these medications, and recent changes in how ADHD is diagnosed in the new edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-V) — the authors believe that “it is highly likely that across the next 5 years, rates of youth ADHD will climb … to perhaps 13% in terms of lifetime diagnoses, or between one in eight and one in seven. This would mean that the rate for boys would be as high as one in six to one in five” (161).This dramatic increase in diagnoses and stimulant drug treatment in one generation makes it look like an epidemic. But “it's not. It's preposterous,” says Keith Conners (quoted in Schwarz 2013), a psychologist and professor emeritus at Duke University who pioneered stimulant treatment for ADHD with Leon Eisenberg in 1963 (Mayes, Bagwell, and Erkulwater 2009: 60–61). As Hinshaw and Scheffler explain, the primary drivers of this massive growth include (1) compulsory education and greatly expanded high-stakes testing associated with new education laws like No Child Left Behind (NCLB); (2) changes in government regulations in 1997 that allowed for direct-to-consumer advertising; (3) increased ADHD diagnoses and stimulant use in the past decade among Medicaid-eligible and minority populations; and (4) increasing pressures on health professionals such as pediatricians who make the majority of diagnosis and treatment decisions and who have relatively less training and time to spend with patients than most psychiatrists and psychologists.Hinshaw and Scheffler's main argument is that larger societal changes have driven the marked increase in diagnoses and stimulant prescriptions:The core symptoms linked to ADHD became apparent to societies when children were made to attend school and perform difficult tasks that human brains and minds never evolved to do, like learning to read. In other words, compulsory education was the trigger for revealing the children's different attentional and learning styles. If compulsory education was the initial culprit, the fast-escalating rates of diagnosis and treatment we now see are linked to intense pressures for achievement and performance in the context of an increasingly competitive world economy. Thus, ADHD reveals itself in cultures and nations that place a premium on performance. In short, biology matters, but the context of today's pressured world brings ADHD symptoms to the fore. (xxvii–xxviii)Or, as Malcolm Gladwell (1999: 84) argued presciently back in the late 1990s, “the rise of A.D.H.D. is a consequence of what might otherwise be considered a good thing: that the world we live in increasingly values intellectual consideration and rationality — increasingly demands that we stop and focus. Modernity didn't create A.D.H.D. It revealed it.”In support of their contention that environmental factors play such a large role in the rate of ADHD diagnoses, Hinshaw and Scheffler incorporate discussion (chap. 5) from their own primary research on geographic variation in diagnosis and stimulant-use rates. This variation is consistent with the kinds of regional variation found in many areas of health care services by the researchers who create the Dartmouth Atlas. While the South and Midwest regions include states wherein 13–15.5 percent of all children have received an ADHD diagnosis, most states in the West range, on average, from 5.5 to 7 percent (69). In addition, children diagnosed with ADHD in southern states were much more likely to receive stimulant medications than children diagnosed with ADHD in western states. The authors show that a comparison between how ADHD is diagnosed and treated in North Carolina and California is especially illustrative of “the broad forces at play related to this disorder” (69). Statistically, by “living in North Carolina instead of California, the chances that a child would be diagnosed with ADHD were two and a half times higher. For boys in North Carolina aged 9 and over, the probability of an ADHD diagnosis in 2007 was between 25 and 30% — a startling rate of one in four to one in three. Furthermore, the probability of receiving [stimulant] medication was 50% higher in North Carolina than in California” (70). Hinshaw and Scheffler find that differences in schools and school policies between the two states are major contributors to these significant differences. Unlike California, North Carolina was one of the first states in the United States to implement strict school accountability and high-stakes testing laws. North Carolina's southern neighbors were ahead of many other states in the country in this regard, as “15 of the 17 states in the South had consequential accountability laws in place prior to NCLB, a far higher rate than for any other region” (79). Once NCLB and its performance requirements were fully implemented across the United States, other regions began to witness increased rates of ADHD diagnoses and stimulant use that have narrowed the gap between southern and nonsouthern states.The fact that ADHD diagnosis and medication rates vary so much geographically raises a critical issue: the inherent and unavoidable subjectivity involved in most mental diagnoses (including ADHD). Unlike infectious diseases such as Ebola or HIV, in which a person categorically does or does not have the disease, mental diagnoses are often on a spectrum of “more” or “less”: anxious, depressed, obsessive, fearful, impulsive, inattentive, hyperactive, and so forth. The cut points on the spectrum between normal and abnormal are imprecise, shift over time, and vary somewhat from one area to the next in terms of how observers determine them. The subjectivity of ADHD diagnoses has been highlighted by recent findings that the youngest children in any given grade are much more likely (70–80 percent more likely) to be diagnosed with the disorder than their older classmates, mostly because they are that much less mature relative to their peers (Morrow et al. 2012. The diagnosis of ADHD is not the only one with this imprecision. High blood pressure presents a similar judgment call as to when someone has crossed from healthy-normal to unhealthy-hypertension and is at increased risk for cardiovascular disease. When diagnostic criteria are on a continuous spectrum requiring arbitrary cut points, errors are common.Fee-for-service reimbursement that promotes volume of care and the default impulse of most allied health professionals to try to help also contribute to the overdiagnosis of ADHD and misuse of stimulants in some areas and populations. Other comparable examples include the overuse of the following: statins for treatment of high cholesterol, erectile dysfunction drugs for men with subclinical symptoms, antidepressants for people with mild depression, stents for stable coronary artery disease, and PSA tests and mammograms for prostate and breast cancer screening, respectively (Brownlee 2008; Welch 2012).What is different about the misdiagnosis of ADHD and the related overuse of stimulants is that they are more likely to raise heated debates about competitive fairness. Unlike statins, stents, cancer screenings, drugs for erectile dysfunction, and other medical services and pharmaceuticals, stimulants help most people — with and without ADHD — focus better and for longer periods of time. Thus the illicit use of stimulants by students and adults is usually framed as analogous to athletes unfairly using performance-enhancing drugs to gain an unethical edge. Yet focusing so much on the misdiagnosis of ADHD (false positives) and overuse of stimulants, Hinshaw and Scheffler explain, obscures the very real and extensive damage done to individuals and society when underdiagnosis occurs. Children with untreated ADHD, who could improve dramatically in school and in their personal lives, often end up struggling unnecessarily, and many of them realize far less of their human potential as spouses, workers, parents, taxpayers, friends, and colleagues. These “errors” of missing ADHD diagnoses rarely rise to a level of public concern or outrage, but they are no less problematic or consequential.Invariably, at the heart of the controversy over ADHD are timeless and universal questions of boundary drawing. Despite the fact that scientific research can inform our understanding of mental disorders and our approach to making better diagnoses, where the boundary between ADHD and typical childhood behavior is located is a political and social choice, not a scientific one. No amount of clinical research can resolve this question for us. Social, political, educational, familial, and economic forces impinge on where clinicians, educators, program administrators, and others decide to locate the boundaries of disorder. Additionally, to the extent that the boundary between sickness and health is — in the case of mental disorders such as ADHD — demarcated without the ability to reference objective clinical signs or indicators, debates about under- or overdiagnosis invariably tap into society's ambivalence and even skepticism about some mental disorders.The debates surrounding ADHD and stimulants, then, are not over the comparatively smaller number of children with clear and extreme cases of ADHD, which often coexist with other problems such as depression, learning disabilities, and conduct disorders. The debates center, instead, on the significantly larger number of children with less clear behavioral symptomology — or those with a shadow of ADHD in the form of mild-to-moderate behavioral difficulties — using stimulants when there is legitimate disagreement over how best to treat them. Ultimately, criticisms of mental disorders like ADHD are criticisms both of the limits of clinical knowledge and of the extraclinical forces that influence diagnostic decision making. For those wanting to better understand all these aspects and implications associated with ADHD and stimulants, as well as the controversies surrounding them, this book is one of the best places to start.