Executive functioning in schizophrenia: A thorough examination of performance on the Hayling Sentence Completion Test compared to psychiatric and non-psychiatric controls Nicole Joshua a,b, ⁎, Andrea Gogos a,b , Susan Rossell a,b,c a Mental Health Research Institute of Victoria, Level 2, 161 Barry Street, Carlton South Victoria 3053, Australia b The University of Melbourne, Parkville Victoria 3010, Australia c Monash–Alfred Psychiatry Research Centre, Monash University School of Psychology, Psychiatry and Psychological Medicine, The Alfred Hospital, Victoria, 3004, Australia article info abstract Article history: Received 20 January 2009 Received in revised form 28 May 2009 Accepted 29 May 2009 Available online 21 June 2009 Background: The current study examined executive functioning in schizophrenia by assessing response initiation and suppression in a group of schizophrenia patients, and drawing comparisons with psychiatric and non-psychiatric control groups. Method: The Hayling Sentence Completion Test was used as a measure of executive functioning and was completed by 39 schizophrenia patients, 40 bipolar disorder patients and 44 healthy control participants. Outcome measures included response initiation and response suppression latency and error rate. Results: The schizophrenia group was significantly impaired on all measures of the Hayling Sentence Completion Test when compared to healthy control participants, and only on some of the measures when compared to the bipolar disorder group. The bipolar disorder group did not differ in performance compared to the healthy control group. Overall schizophrenia patients showed longer response initiation and response suppression latencies, and an increased error rate. Performance of the schizophrenia patients was associated with higher ratings of cognitive disorganisation. Performance was not related to age, gender, predicted IQ or any other clinical characteristics. Conclusions: Schizophrenia patients show a slowing in baseline response initiation and slowed suppression of an inappropriate response. Considering the bipolar disorder patients demonstrated intact performance, altered executive functioning in schizophrenia appears relatively specific to the disorder rather than reflecting other characteristics common to mental illness. Investigations examining which neurocognitive domains are impaired in schizophrenia provide direct implications for treatment options tailored to an individual's cognitive strengths and weaknesses. © 2009 Elsevier B.V. All rights reserved. Keywords: Schizophrenia Executive functioning Inhibition Suppression Bipolar disorder Hayling Sentence Completion Test 1. Introduction Neurocognitive impairment is considered a core feature of schizophrenia (Elvevag and Goldberg, 2000), with impair- ment relatively resistant to antipsychotic medication (Gold- berg et al., 1993). Impairment is apparent early in the illness, as it is observed in first episode patients (Saykin et al., 1994). Longitudinal studies have revealed no difference in the degree of impairment between first episode and previously treated patients, both initially and at 19-month follow-up (Censits et al., 1997), thus indicating that deficits are stable over the course of the illness. Individuals at high-risk for developing schizophrenia, i.e. first-degree relatives, also exhibit deficits, suggesting a familial link (Byrne et al., 1999; Faraone et al., Schizophrenia Research 114 (2009) 84–90 ⁎ Corresponding author. Mental Health Research Institute of Victoria, Level 2, 161 Barry Street, Carlton South Victoria 3053, Australia. Tel.: +61 3 8344 1853; fax: +61 3 9348 1778. E-mail addresses: nickijoshua@gmail.com (N. Joshua), agogos@mhri.edu.au (A. Gogos), susan.rossell@med.monash.edu.au (S. Rossell). 0920-9964/$ – see front matter © 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.schres.2009.05.029 Contents lists available at ScienceDirect Schizophrenia Research journal homepage: www.elsevier.com/locate/schres