Attention-deficit hyperactivity disorder (ADHD) affects 8% of school age children. It presents with symptoms of inattention, hyperactivity/impulsivity, or both. Currently, three subtypes of ADHD are defined: ADHD inattentive (ADHD/I), ADHD hyperactive/impulsive (ADHD/H) and ADHD combined (ADHD/C). However, in the last decade heated debate has emerged that questions how this disorder should be conceptualized, defined, and categorized. Key questions have been: "Is it a category or a continuum?" and "How do comorbidities relate to currently defined subtypes?" In these interactive, evidence-based neuroscienceCME Journal Club sessions, the faculty will explore new data that may re-focus how we view ADHD subtypes. Such exploration will allow clinicians to anticipate how developers of the DSM-V might revise ADHD diagnostic criteria. As a result, clinicians will be in a position of opportunity to achieve better individualization of therapy. Featured Article: Mayes SD, Calhoun SL, Bixler EO, et al. ADHD subtypes and comorbid anxiety, depression, and oppositional-defiant disorder: differences in sleep problems. J Pediatr Psychol. 2009;34(3):328-337.