Self-reported cognitive decline on the informant questionnaire on cognitive decline in the elderly is associated with dementia, instrumental activities of daily living and depression but not longitudinal cognitive change

Background/Aim: A subjective history of cognitive decline is integral to dementia screening, yet there are few data on the accuracy of retrospective self-reports. We prospectively examined the longitudinal predictors of self-reported decline, including rate of cognitive change, clinical diagnosis, depressive symptoms and personality. Methods: We used a large (n = 2,551) community-dwelling sample of older adults (60-64 years at baseline) and tracked their cognitive functioning over 3 waves across a period of 8 years. Individual rates of change in multiple domains of cognition, incident dementia and mild cognitive disorders, apolipoprotein E (APOE) ε4 genotype, level of education, depressive symptoms and personality were examined as predictors of wave 3 retrospective self-reported decline as measured by the Informant Questionnaire on Cognitive Decline in the Elderly. Results: The rate of cognitive decline did not predict subjective decline. Significant predictors of self-reported decline included dementia diagnosis, problems with instrumental activities of daily living, depression and neuroticism at the time of self-report, as well as the presence of an APOE ε4 allele. Conclusions: In this relatively young cohort, retrospective self-report of cognitive decline does not reflect objective deterioration in cognition over the time period in question, but it may identify individuals in the initial stages of dementia and those with elevated psychological and genotypic risk factors for the development of dementia.