The 'cognitive footprint' of psychiatric and neurological conditions: cross-sectional study in the UK Biobank cohort.

Objective 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. Method 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. Results 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. Conclusion Although the relative prevalence of cognitive impairment was lowest in major depression, the population attributable prevalence was highest overall for this group. [ABSTRACT FROM AUTHOR]