Executive function in first-episode schizophrenia: A three-year longitudinal study of an ecologically valid test

• Published in: Schizophrenia research Vol. 126; no. 1; pp. 87 - 92
• Main Authors: Liu, Kristy C.M, Chan, Raymond C.K, Chan, Kevin K.S, Tang, Jennifer Y.M, Chiu, Cindy P.Y, Lam, May M.L, Chan, Sherry K.W, Wong, Gloria H.Y, Hui, Christy L.M, Chen, Eric Y.H
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.03.2011; Elsevier
• Subjects: Adult; Adult and adolescent clinical studies; Age of Onset; Analysis of Variance; Biological and medical sciences; Cognition Disorders - etiology; Cognitive function; Executive function; Executive Function - physiology; Female; First-episode schizophrenia; Humans; Intelligence; Longitudinal; Longitudinal Studies; Male; Medical sciences; Medication-naïve; Neuropsychological Tests; Psychiatric Status Rating Scales; Psychiatry; Psychology. Psychoanalysis. Psychiatry; Psychopathology. Psychiatry; Psychoses; Schizophrenia; Schizophrenia - complications; Schizophrenic Psychology; Six elements; Young Adult; Medication-naïve; Executive function; First-episode schizophrenia; Longitudinal; Six elements; Cognitive function; Human; Schizophrenia; Cognition; Psychosis; Treatment; First episode; Follow up study; Ecological approach; Medication-naive
• ISSN: 0920-9964; 1573-2509
• DOI: 10.1016/j.schres.2010.11.023

Abstract 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.