In many western countries, attention deficit hyperactivity disorder (ADHD) has achieved celebrity status, such that it probably no longer requires introduction. The disorder is a global phenomenon, spreading rapidly as result of the increasing dominance internationally of US psychiatric models, the need for new markets for major pharmaceutical companies, increasing use of the internet by parents and professionals and changing approaches to schooling. There is a broad consensus among international experts and organisations that ADHD is a genuine neurodevelopmental disorder based on empirical research. However, many critics have questioned the legitimacy of ADHD. This paper reviews the arguments for and against the ADHD construct. First, the review examines the literature and research endorsing ADHD as a "real" disorder. Second, the criticisms levelled against the ADHD construct are examined.