Cognitive assessment occurred as soon as possible after admission. Patients were administered a comprehensive battery of tests that took approximately 4 hours to complete. Since the battery was updated periodically to integrate new research findings and to maximize coverage of all cognitive domains, sample size varied among tests. The battery included the Finger Tapping Test (average number of finger taps in 10 seconds),21 Trail Making Test (time to completion),22 Continuous Performance Test (number of hits),23 Benton Visual Retention Test (number of correct responses),24 Logical Memory Test, Wechsler Memory Scale–Revised (immediate recall, delayed recall, and percentage saving scores),25 Rey Auditory Verbal Learning Test (immediate recall, delayed recall, and recognition),26 Rey-Osterreith Complex Figure Test (copy, immediate recall, delayed recall, and percentage saving scores),27,28 Wisconsin Card Sorting test (WCST) (number of categories and perseverative errors),29 Word Fluency Test (number of words generated in 3 minutes in response to the letters C, F, L),30 and Stroop Test (number correct on card 3 in 45 seconds and the calculated interference score).31 In addition, the following subscales from the WAIS-R were administered: digit span, digit symbol, vocabulary, information, comprehension, similarities, block design, object assembly, picture arrangement, and picture completion. Tests were administered by psychometrists who were trained in standardized assessment and had experience working with patients with schizophrenia. They all had at least an undergraduate degree in psychology and were supervised by a psychologist with a PhD degree.