title: The 'cognitive footprint' of psychiatric and neurological conditions: cross-sectional study in the UK Biobank cohort.
abstract: We aimed to quantify the prevalence of cognitive impairment in adults with a history of mood disorder, schizophrenia, multiple sclerosis or Parkinson's disease, within a large general population cohort.
  
  
  
  Cross-sectional study using UK Biobank data (n = 502 642). Psychiatric and neurological exposure status was ascertained via self-reported diagnoses, hospital records and questionnaires. Impairment on reasoning, reaction time and memory tests was defined with reference to a single unexposed comparison group. Results were standardised for age and gender. Sensitivity analyses examined the influence of comorbidity, education, information sources and missing data.
  
  
  
  Relative to the unexposed group, cognitive impairment was least common in major depression (standardised prevalence ratios across tests = 1.00 [95% CI 0.98, 1.02] to 1.49 [95% CI 1.24, 1.79]) and most common in schizophrenia (1.89 [95% CI 1.47, 2.42] to 3.92 [95% CI 2.34, 6.57]). Prevalence in mania/bipolar was similar to that in multiple sclerosis and Parkinson's disease. Estimated population attributable prevalence of cognitive impairment was higher for major depression (256 per 100 000 [95% CI 130, 381]) than for all other disorders.
  
  
  
  Although the relative prevalence of cognitive impairment was lowest in major depression, the population attributable prevalence was highest overall for this group.
authors.affiliation: Institute of Health and Wellbeing, University of Glasgow, Glasgow, UK.
authors.forename: B
authors.identifier: 0000-0002-7259-9505
authors.initials: B
authors.lastname: Cullen
authors.affiliation: Institute of Health and Wellbeing, University of Glasgow, Glasgow, UK.
authors.forename: D J
authors.initials: DJ
authors.lastname: Smith
authors.affiliation: Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh, Edinburgh, UK.
authors.forename: I J
authors.initials: IJ
authors.lastname: Deary
authors.affiliation: Institute of Health and Wellbeing, University of Glasgow, Glasgow, UK.
authors.forename: J J
authors.initials: JJ
authors.lastname: Evans
authors.affiliation: Institute of Health and Wellbeing, University of Glasgow, Glasgow, UK.
authors.forename: J P
authors.initials: JP
authors.lastname: Pell
mesh_terms: D000367:Age Factors; D060825:Cognitive Dysfunction / Q000453:epidemiology* / Q000209:etiology / Q000523:psychology; D003430:Cross-Sectional Studies; D003865:Major Depressive Disorder / Q000150:complications / Q000453:epidemiology / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D001523:Mental Disorders / Q000150:complications / Q000453:epidemiology* / Q000523:psychology; D008875:Middle Aged; D019964:Mood Disorders / Q000150:complications / Q000453:epidemiology / Q000523:psychology; D009103:Multiple Sclerosis / Q000150:complications / Q000453:epidemiology* / Q000523:psychology; D010300:Parkinson Disease / Q000150:complications / Q000453:epidemiology* / Q000523:psychology; D015995:Prevalence; D012307:Risk Factors; D012559:Schizophrenia / Q000150:complications / Q000453:epidemiology; D012737:Sex Factors; D006113:United Kingdom / Q000453:epidemiology
keywords: Cognitive Dysfunction; mood disorders; neurological disorders; prevalence; schizophrenia