It has been suggested that the recent rapid developments in the fields of neuroscience and psychopharmacology have increased the possibilities for pharmacological enhancement of mental functioning. Here, evidence is reviewed which shows that drugs acting on a variety of neurotransmitter systems can indeed enhance cognition, and to a lesser extent mood and pro-social behavior. Moreover, it seems possible to interfere with the (re)consolidation of traumatic memories. There are, however, a number of caveats: first, as cognition-enhancing drugs can simultaneously exert both linear and quadratic (U-shaped) effects, doses most effective in facilitating one behavior could at the same time exert null or even detrimental effects on other cognitive domains. Second, individuals with a 'low memory span' might benefit from cognition-enhancing drugs, whereas 'high span subjects' are 'overdosed'. And finally, evidence suggests that a number of trade-offs could occur. For example, increases of cognitive stability might come at the cost of a decreased capacity to flexibly alter behavior. A short overview of ethical issues raised by the use of cognition and mood enhancing drugs demonstrates the tremendous variety in views and opinions regarding the subject. (C) 2008 Elsevier Ltd. All rights reserved.