Abstract Attention-Deficit Hyperactivity Disorder (ADHD) is estimated to affect up to 5 million school age American children. With so many children affected, it is important to understand the landscape in which they are diagnosed to ensure that the right children are receiving the right treatment. The DSM-IV TR lists the behavioral components of ADHD and defines the criteria used to diagnose. While the DSM’s empirically driven benchmarks should be considered the go-to publication for identifying an ADHD child, doctors and clinicians often ignore the publication. This could be because of inconsistencies found within the DSM or logistical limitations mental health care professionals face. In my investigation of the existence of over-diagnosis of ADHD, I analyze these limitations and explore research papers that approach the topic. The paper concludes with analysis of the findings. Is Attention-Deficit Hyperactivity Disorder Over-Diagnosed? In 1902, Sir George Frederic Still was the first doctor to formally conceptualize and define the traits associated Attention-Deficit Hyperactivity Disorder (ADHD). Still described children with the disorder as having a “defect of moral control as a morbid manifestation, without general impairment of intellect and without physical disease” (Lange, Reichl, Tucha & Tucha, 2010). Modern science no longer considers immoral actions as a defining characteristic of ADHD. Current clinical descriptions of ADHD focus on manifestations of inattentive, impulsive, and overactive behavior in multiple environments (Barkley, 2003). Contemporary characteristics that define an ADHD child have been built upon the foundation that Sir George Still laid. His work gives weight to the notion that children with this disorder were present in societies long before it was defined and accepted by the scientific community. Despite the disorder’s history, there are some in the scientific community that feel that ADHD is over-diagnosed because it is currently a trendy diagnosis (Sciutto & Eisenberg, 2007). The purpose of this review is to critically examine the potential existence of the over-diagnosis of ADHD. My investigation will include a critical evaluation of the disorder as defined in the Diagnostic and Statistical Manual of Mental Disorders, 4th ed., text rev. (DSM – IV TR), an exploration of the criteria for diagnosing and an evaluation of research studies focusing on clinical practices in diagnosing ADHD children. I will then analyze research studies that focus on investigating over-diagnosis. In concluding the review, I will draw a conclusion to the conception of over-diagnosis of ADHD and explain why I have come to such a conclusion. ADHD: The Definition and the Diagnosis ADHD is estimated to affect approximately 3 to 7 % of school-age children (Sciutto & Eisenberg 2007). Children with ADHD are characterized by persistent patterns of difficulties with attention, hyperactivity, impulsivity, behavior control, and defiant behavior (Woo & Keatinge, 2008). However, it is not enough to just show the symptoms, they must have a negative impact on the child’s continued development. A foundational aspect of criterion validity for a mental disorder is evidence that the disorder is associated with distress or functional impairment that is sufficiently severe to warrant intervention (Willcutt et al., 2012). To meet the criteria for a diagnosis of ADHD, there are several symptoms that must exist and factors that must be considered. First, the DSM-IV TR requires that symptoms must be persistent for at least 6 months (APA, 2010). This prevents clinicians from making hasty diagnosis based on symptoms that may be a result of the child experiencing distress caused by transient situations in their environment. Furthermore, it may encourage a clinician to monitor the child’s behavior over this time period, which would result in a more intimate understanding of the child’s situation. This would not only help confirm a proper diagnosis but also ensure that those symptoms are causing maladaptation and are inconsistent with the child’s developmental level (APA, 2010). The DSM-IV TR then separates symptoms into two categories: Inattention and Hyperactivity/Impulsivity. To meet a diagnosis within either category, 6 or more symptoms must be displayed or reported (APA, 2010). Within the inattention category, symptoms range from difficulty sustaining attention during tasks and instructions from others to difficulty in organization, forgetfulness and avoidance behaviors (APA, 2010). While, hyperactivity lists 6 symptoms and impulsivity only lists 3, both fall under the same diagnostic category (APA, 2010). Hyperactivity symptoms include talking excessively, difficulty playing quietly, fidgeting, leaving seat when remaining seated is expected, excessive running or climbing or acting as if ‘driven by a motor’ (APA, 2010). Impulsivity symptoms are limited to blurting out answers bef