International Journal of Neuroscience, 119:1810–1829, 2009 Copyright C  2009 Informa Healthcare USA, Inc. ISSN: 0020-7454 / 1543-5245 online DOI: 10.1080/00207450903192878 COROLLARY-AND DISCREPANCY-BASED APPROACHES FOR EXAMINING THE APPROPRIATENESS OF PREMORBID COGNITIVE ESTIMATION IN GERIATRIC SCHIZOPHRENIA JESSICA FOLEY University of California, Los Angeles David Geffen School of Medicine, Semel Institute for Neuroscience and Human Behavior Los Angeles, CA, USA CHARLES GOLDEN EDWARD SIMCO BARRY SCHNEIDER ROBERT McCUE LINDSAY SHAW Nova Southeastern University Fort Lauderdale-Davie Florida, USA Objective: This article addresses whether measures for assessing premorbid intellectual functioning are adequate for geriatric schizophrenia. Method: We included geriatric schizophrenia-spectrum disorders (SSD; n = 37), frontotemporal dementia (FTD; n = 41), and geriatric controls (n = 107), and employed measures of verbal ability. Results: Pearson’s correlations and ANOVAs for discrepancy comparisons showed unique patterns of spared function in SSD when compared to FTD and controls. Conclusions: Findings lend support to the specificity of cognitive processes in SSD, even when accounting for processes common to the theoretically similar FTD. SSD showed a distinct pattern of spared ability which supports clinical utilization of discrepant measures of premorbid intellectual estimation for SSD. Address correspondence to Jessica Foley, Ph.D., UCLA School of Medicine/Semel Institute for Neuroscience and Human Behavior, 760 Westwood Plaza #C8-746 Los Angeles, CA, USA 90095. E-mail: jmfoley@ucla.edu 1810