We examined the effect of methylphenidate (Mph) on inhibition and several other cognitive abilities in 43 adults with Attention Deficit Hyperactivity Disorder (ADHD) by use of Conners’ Continuous Performance Test (CPT) and the Change Task (ChT), an extension of the Stop Signal Test (SST). In a double blind, cross-over, placebo controlled study with Mph, tests were administered during the third ...