title: Association between processing speed and subclinical psychotic symptoms in the general population: focusing on sex differences.
abstract: Evidence is growing that persons along the schizophrenia spectrum, i.e., those who also display subclinical psychotic symptoms, exhibit deficits across a broad range of neuropsychological domains. Because sex differences in the association between cognitive deficits and psychosis have thus far been mostly neglected, we believe that ours is the first study specifically focused upon those differences when examining the relationship between subclinical psychosis and processing speed. Using a sample of 213 persons from the general population from Zurich, Switzerland, psychotic symptoms were assessed with three different questionnaires including the Schizotypal Personality Questionnaire, an adaptation of the Structured Interview for Assessing Perceptual Anomalies, and the Paranoia Checklist. Processing speed was assessed with the WAIS digit-symbol coding test. Two higher-order psychosis domains were factor-analytically derived from the various psychosis subscales and then subjected to a series of linear regression analyses. The results demonstrate that in both men and women associations between subclinical psychosis domains and processing speed were weak to moderate (β ranging from -0.18 to -0.27; all p<0.05). However, we found no sex-differences in the interrelation of subclinical psychosis and processing speed (ΔR(2)<0.005; p>0.30). In conclusion, it appears that sex differences in psychosis manifest themselves only at the high end of the continuum (full-blown schizophrenia) and not across the sub-threshold range. The small magnitude of the effects reported herein conforms to the etiopathology of the disorder. Since schizophrenia and related disorders from the spectrum are assumed to be multifactorial diseases, it follows that many etiological components of small effect are involved.
authors.affiliation: Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Switzerland; Institute of Psychiatry, Laboratory of Neuroscience (LIM 27), University of Sao Paulo, Brazil; Zurich Program for Sustainable Development of Mental Health Services, Zurich, Switzerland. Electronic address: wulf.roessler@uzh.ch.
authors.forename: Wulf
authors.initials: W
authors.lastname: Rössler
authors.affiliation: Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Switzerland; Zurich Program for Sustainable Development of Mental Health Services, Zurich, Switzerland.
authors.forename: Vladeta
authors.initials: V
authors.lastname: Ajdacic-Gross
authors.affiliation: Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Switzerland; Zurich Program for Sustainable Development of Mental Health Services, Zurich, Switzerland.
authors.forename: Mario
authors.initials: M
authors.lastname: Müller
authors.affiliation: Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Switzerland; Zurich Program for Sustainable Development of Mental Health Services, Zurich, Switzerland.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Rodgers
authors.affiliation: Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Switzerland.
authors.forename: Wolfram
authors.initials: W
authors.lastname: Kawohl
authors.affiliation: Translational Neuromodeling Unit, Institute for Biomedical Engineering, University of Zurich & ETH Zurich, Switzerland.
authors.forename: Helene
authors.initials: H
authors.lastname: Haker
authors.affiliation: Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Switzerland; Zurich Program for Sustainable Development of Mental Health Services, Zurich, Switzerland; Department of Applied Psychology, Zurich University of Applied Sciences (ZHAW), Zurich, Switzerland.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Hengartner
mesh_terms: D000328:Adult; D003071:Cognition; D003072:Cognition Disorders / Q000453:epidemiology / Q000503:physiopathology / Q000523:psychology*; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D016014:Linear Models; D008137:Longitudinal Studies; D008297:Male; D009483:Neuropsychological Tests; D025341:Principal Component Analysis; D011569:Psychiatric Status Rating Scales; D011618:Psychotic Disorders / Q000453:epidemiology / Q000503:physiopathology / Q000523:psychology*; D012727:Sex Characteristics; D013557:Switzerland / Q000453:epidemiology; D013850:Thinking / Q000502:physiology; D013997:Time Factors; D055815:Young Adult
keywords: Cognitive deficits; Processing speed; Psychotic-like experiences; Schizophrenia spectrum; Schizotypy; Sex differences; Subclinical psychosis