James Gilleen1, Marcello Tesse2, Tjasa Velikonja3, Mark Weiser4, Michael Davidson4, Abraham Reichenberg5. 1. Department of Psychology, University of Roehampton, London, UK; Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK. Electronic address: james.gilleen@roehampton.ac.uk. 2. Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK. 3. Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, USA. 4. Department of Psychiatry, Sheba Medical Centre, Tel Hashomer, Israel. 5. Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK; Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, USA.
Abstract
BACKGROUND: Cognitive deficits, particularly in processing speed, are widely recognized as a critical feature of schizophrenia, and are also present across schizophrenia spectrum disorders. A number of important confounders, however, such as hospitalization effects and antipsychotic medication, have been shown to affect processing speed, causing debate as to the core cognitive deficits of schizophrenia. The study of individuals who are not clinically psychotic but have schizotypal traits allows investigation of cognitive deficits associated with both positive and negative schizotypy dimensions while excluding potential confounds. METHODS: A population-based community sample of 242 healthy adult volunteers assessed using the Structured Interview of Schizotypy - Revised (SIS-R) scale, and a neuropsychological testing battery that included measures of verbal ability, visual and verbal memory, verbal fluency, working memory, executive functions and processing speed. Participants were classified in High or Low Positive Schizotypy (H-PST or L-PST), High or Low Paranoia-like traits (H-PAR or L-PAR) and High or Low Negative Schizotypy (H-NST or L-NST) groups, respectively. RESULTS: Individuals with H-PST performed significantly (p < 0.05) worse than L-PST on measures of processing speed and executive functions. Processing speed deficits were also observed in individuals with H-PAR compared to L-PAR (p < 0.05). There were no statistically significant differences in neuropsychological performance between H-NST and L-NST on any measure. CONCLUSIONS: In a population-based community sample, individuals with high positive schizotypal traits or paranoia-like traits show impairments in processing speed. Consistent with a dimensional view of psychosis, this supports the hypothesis that processing speed represents a core deficit of schizophrenia-like mental states.
BACKGROUND:Cognitive deficits, particularly in processing speed, are widely recognized as a critical feature of schizophrenia, and are also present across schizophrenia spectrum disorders. A number of important confounders, however, such as hospitalization effects and antipsychotic medication, have been shown to affect processing speed, causing debate as to the core cognitive deficits of schizophrenia. The study of individuals who are not clinically psychotic but have schizotypal traits allows investigation of cognitive deficits associated with both positive and negative schizotypy dimensions while excluding potential confounds. METHODS: A population-based community sample of 242 healthy adult volunteers assessed using the Structured Interview of Schizotypy - Revised (SIS-R) scale, and a neuropsychological testing battery that included measures of verbal ability, visual and verbal memory, verbal fluency, working memory, executive functions and processing speed. Participants were classified in High or Low Positive Schizotypy (H-PST or L-PST), High or Low Paranoia-like traits (H-PAR or L-PAR) and High or Low Negative Schizotypy (H-NST or L-NST) groups, respectively. RESULTS: Individuals with H-PST performed significantly (p < 0.05) worse than L-PST on measures of processing speed and executive functions. Processing speed deficits were also observed in individuals with H-PAR compared to L-PAR (p < 0.05). There were no statistically significant differences in neuropsychological performance between H-NST and L-NST on any measure. CONCLUSIONS: In a population-based community sample, individuals with high positive schizotypal traits or paranoia-like traits show impairments in processing speed. Consistent with a dimensional view of psychosis, this supports the hypothesis that processing speed represents a core deficit of schizophrenia-like mental states.
Authors: Ian Kelleher; Aileen Murtagh; Mary C Clarke; Jennifer Murphy; Caroline Rawdon; Mary Cannon Journal: Cogn Neuropsychiatry Date: 2012-09-20 Impact factor: 1.871
Authors: Jolanta Zanelli; Abraham Reichenberg; Kevin Morgan; Paul Fearon; Eugenia Kravariti; Paola Dazzan; Craig Morgan; Caroline Zanelli; Arsime Demjaha; Peter B Jones; Gillian A Doody; Shitij Kapur; Robin M Murray Journal: Am J Psychiatry Date: 2009-12-01 Impact factor: 18.112