Executive function in first-episode schizophrenia: A three-year longitudinal study of an ecologically valid test Kristy C.M. Liu a , Raymond C.K. Chan b , Kevin K.S. Chan a , Jennifer Y.M. Tang a , Cindy P.Y. Chiu a , May M.L. Lam a , Sherry K.W. Chan a , Gloria H.Y. Wong a , Christy L.M. Hui a , Eric Y.H. Chen a, ⁎ a Department of Psychiatry, The University of Hong Kong, Queen Mary Hospital, 102 Pokfulam Road, Hong Kong b Neuropsychology and Applied Cognitive Neuroscience Laboratory, Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, 4A Datun Road, Beijing 100101, China article info abstract Article history: Received 16 July 2010 Received in revised form 13 November 2010 Accepted 29 November 2010 Available online 30 December 2010 Executive function impairment is a key cognitive deficit in schizophrenia. However, traditional neuropsychological tests of executive function may not be sensitive enough to capture the everyday dysexecutive problems experienced by patients. Additionally, existing literature has been inconsistent about longitudinal changes of executive functions in schizophrenia. The present study focuses on examining the longitudinal change of executive functions in schizophrenia using the Modified Six Elements Test (MSET) that was developed based on the Supervisory Attentional System model and shown to be sensitive to everyday dysexecutive problems. In the present study, MSET performance was assessed in 31 medication-naïve first- episode schizophrenic patients at four times over a period of three years, while the 31 normal controls were assessed once. Patients demonstrated impairment in MSET as compared to controls. Importantly, the MSET impairment persisted from the medication-naïve state to clinical stabilization and the three years following the first psychotic episode though patients improved in a conventional executive test (Modified Wisconsin Card Sorting Test). Performance was not related to intelligence, educational level, symptom changes, age-of- onset, or duration of untreated psychosis. Better MSET performance at medication-naïve state predicted improvement in negative and positive symptoms over the three-year period. These findings may suggest that MSET impairment is a primary deficit in schizophrenia that occurs early in the course of the illness and remains stable irrespective of clinical state for at least three years following the first episode of schizophrenia. © 2010 Elsevier B.V. All rights reserved. Keywords: First-episode schizophrenia Medication-naïve Longitudinal Cognitive function Executive function Six elements 1. Introduction Executive impairment is one of the most robust and central deficits to be associated with schizophrenia and is seen across stages of the illness (Chan et al., 2006a,b; Fioravanti et al., 2005; Rund, 2002). Schizophrenic patients tend to show impairment in tests sensitive to frontal lobe lesions, including Wisconsin card sorting, verbal fluency and trail making (Chan et al., 2006b; Liddle and Morris, 1991). The neuropsychological tests traditionally used in exam- ining executive functions may not be sufficiently sensitive to detect the dysexecutive syndrome experienced by patients in everyday life. Studies have shown that even though people with frontal lobe lesions exhibit many characteristics of a dysexecutive syndrome in their daily lives, some may not demonstrate impairment on performing conventional exec- utive tests (Shallice and Burgess, 1991). To better capture the everyday executive functioning in patients, the Modified Six Elements Test (MSET) was incorporated into the Behavioural Assessment of the Dysexecutive Syndrome (BADS; Wilson et al., 1996). In the MSET, subjects have to plan their time so as to complete at least part of each of the six subtasks while at Schizophrenia Research 126 (2011) 87–92 ⁎ Corresponding author. Tel.: + 852 2255 4488; fax: + 852 2255 1345. E-mail address: eyhchen@hku.hk (E.Y.H. Chen). 0920-9964/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.schres.2010.11.023 Contents lists available at ScienceDirect Schizophrenia Research journal homepage: www.elsevier.com/locate/schres