The chapter begins with some elaboration about the nature of the generalized cognitive impairment in schizophrenia. A number of large meta-analyses have provided clarifying evidence about the breadth of this deficit. Heinrichs and Zakzanis published the first large-scale meta-analysis of cognitive deficit findings in schizophrenia. Articles for the meta-analysis were located through key word searches in PubMed for the period 2006 to 2011. Standard criteria were used to select studies/samples for review: the study must have contrasted cognitive performance in schizophrenia patients and healthy controls; the study must have based schizophrenia diagnoses on contemporary diagnostic criteria; results must have been reported with sufficient detail to allow calculation of effect sizes; finally, the study must have been reported in English. Neuropsychological battery studies make it possible to compare schizophrenia cognitive deficits in different global regions using the same or very similar cognitive tests.