ADHD is a neurobehavioral disorder that usually appears in early childhood before the age of 7. It is characterized by varying degrees of inattention, hyperactivity/impulsivity, and impairments in executive functioning, such as self-regulation, motivation, effort, processing speed, cognitive flexibility, organization, and planning. The prevalence of ADHD is estimated to be between 3-10% of school-aged children. Between 50-80% of them meet criteria for ADHD in adulthood; it is estimated that between 1.5-8% of the adult population has ADHD.

However, the symptoms of a variety of other medical, psychiatric, and developmental disorders, as well as environmental and social stressors frequently mimic the symptoms of ADHD in both children and adults. Thus, these statistics may be inaccurate. This article illustrates the importance of conducting a comprehensive, rather than focused assessment in order to rule out other frequently occurring causes of presenting symptoms.