Attention-Deficit/Hyperactivity Disorder (ADHD), as defined by DSM-IV, is a heterogeneous syndrome affecting an estimated 7% of children. Many will continue to have clinically-significant features of ADHD as adults, although some patients referred to adult psychiatrists have previously-unrecognised ADHD. Studies involving neurocognitive assessments or brain imaging have indicated ADHD-associated brain dysfunctions. An important therapeutic role for drugs such as methylphenidate has been clearly established in children and the benefits of medication for ADHD in adults are being increasingly recognised. The present review is aimed at adult psychiatrists who are considering or managing drug treatments for ADHD in adult patients. The focus is on medication regimes, but relevant background literature is also reviewed, as an awareness of a range of published evidence is necessary when assessing ADHD in adult patients and advising on possible drug treatments.