OBJECTIVES: In May 2013, the American Psychiatric Association released the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) which is a classification system for psychiatric and certain neurologic conditions.  DSM-5 brings significant changes to many diagnostic categories as compared to the previous edition of the manual.  The objective of this review was to examine the changes in the Attention-Deficit/Hyperactivity Disorder (ADHD) criteria and discuss the impact these changes may have for industry. METHODS: A line-by-line review of the DSM-5 and DSM-IV criteria for ADHD was undertaken.  Significant changes were highlighted and discussed from the point of view of sponsors of clinical trials for psychopharmacologic agents being developed to treat ADHD. RESULTS: One of the more notable changes to ADHD criteria in DSM-5 is in the age of onset cutoff.  To meet DSM-IV criteria, symptoms had to be present before age 7.  In DSM-5 this was changed to 12.  Additionally, symptoms present before the age of onset cutoff had to cause impairment to meet the DSM-IV criteria, but in DSM-5 there is no such requirement.  Another significant change lies in the fact that while DSM-IV did not make a distinction between childhood and adult ADHD, in DSM-5, from age 17 on, only 5 of 9 symptoms in one or both categories are required, rather than 6.  Several other changes related to differential diagnosis and functional impairment were noted as well. CONCLUSIONS: The significant changes in DSM-5 pose both challenges and opportunities for industry.  The changes in the DSM-5 criteria may translate into changes for how we go about developing medical products to treat psychiatric disorders, including ADHD.  There will need to be an investment in research and education, and sponsors must examine the possibility of developing new endpoints and outcome assessments for use in clinical trials.