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Large population-based cohort studies offer the chance to assess a broad number of diseases and intermediate phenotypes and to estimate their frequencies in the general population. Because of their large sample size new symptom clusters and interactions of genetic, environmental and clinical factors in the onset and course of disease can be described. The German National Cohort (GNC) is one of the mega cohorts with a study-specific concept for the assessment of different psychiatric diseases and a focus on affective disorders and on emotional and cognitive functions. Aim of this manuscript is to describe different design approaches for a priorisation in the assessment of phenotypes for psychiatric and/or neurological disorders in large cohorts and to introduce the concept of studying emotional and cognitive functions and related disorders in GNC. [ABSTRACT FROM AUTHOR]

Objectives. Evaluate the block-adaptive number series task of reasoning, as a time-efficient proxy of general cognitive ability in the Level-2 sample of the German National Cohort (NAKO), a population-based mega cohort. Methods. The number series task consisted of two blocks of three items each, administered as part of the touchscreen-based assessment. Based on performance on the first three items, a second block of appropriate difficulty was automatically administered. Scoring of performance was based on the Rasch model. Relations of performance scores to age, sex, education, study centre, language proficiency, and scores on other cognitive tasks were examined. Results. Except for one very difficult item, the data of the remaining 14 items showed sufficient fit to the Rasch model (Infit: 0.89-1.04; Outfit: 0.80-1.08). The resulting performance scores (N = 21,056) had a distribution that was truncated at very high levels of ability. The reliability of the performance estimates was satisfactory. Relations to age, sex, education, and the executive function factor of the other cognitive tasks in the NAKO supported the validity. Conclusions. The number series task provides a valid proxy of general cognitive ability for the Level-2 sample of the NAKO, based on a highly time-efficient assessment procedure. [ABSTRACT FROM AUTHOR]

Objectives: To describe the cognitive test battery of the German National Cohort (NAKO), a population-based mega cohort of 205,000 randomly selected participants, and to examine associations with demographic variables and selected psychiatric and neurological conditions. Methods: Initial data from 96,401 participants providing data on the cognitive performance measured by a brief cognitive test battery (12-word list recall task, semantic fluency, Stroop test, digit span backwards) was examined. Test results were summarised in cognitive domain scores using exploratory and confirmatory factor analyses. Associations with sociodemographic and psychiatric factors were analysed using linear regression and generalised additive models. Results: Cognitive test results were best represented by two domain scores reflecting memory and executive functions. Lower cognitive functions were associated with increasing age and male sex. Higher education and absence of childhood trauma were associated with better cognitive function. Moderate to severe levels of anxiety and depression, and a history of stroke, were related to lower cognitive function with a stronger effect on executive function as compared to memory. Some associations with cognition differed by German language proficiency. Conclusions: The NAKO cognitive test battery and the derived cognitive domain scores for memory and executive function are sensitive measures of cognition. [ABSTRACT FROM AUTHOR]