Long-term anticholinergic, benzodiazepine and Z-drug use in community-dwelling older adults: What is the impact on cognitive and neuropsychological performance?

Background Long-term use of anticholinergics, benzodiazepines and related drugs (or "Z-drugs") have been associated with cognitive impairment and dementia. However, the relationship of these medications with cognitive function and domain-specific neuropsychological performance in older adults without dementia, is unclear. Methods 5135 older adults (74.0 +/- 8.3 years; 67.4% female) without a diagnosis of dementia were recruited in Ireland to the Trinity-Ulster-Department of Agriculture (TUDA) study. Detailed cognitive and neuropsychological assessment was conducted using the Mini-Mental State Examination (MMSE), Frontal Assessment Battery (FAB) and Repeatable Battery for Assessment of Neuropsychological Status (RBANS). Results A total of 44% (2259 of 5153) used either a potential or definite anticholinergic medication. Overall, 9.7% (n = 500) used a definite anticholinergic medication. Regular benzodiazepine use was reported by 7% (n = 363), whilst 7.5% (n = 387) used a "Z-drug". Use of definite, but not potential anticholinergic medication was associated with poorer performance on all three assessments (beta: -0.09; 95% CI: -0.14, -0.03, p = 0.002 for MMSE; beta: -0.04; 95% CI: -0.06, -0.02; p < 0.001 for FAB; beta: -4.15; 95% CI: -5.64, -2.66; p < 0.001 for RBANS) in addition to all domains of the RBANS. Regular benzodiazepine use was also associated with poorer neuropsychological test performance, especially in Immediate Memory (beta: -4.98; 95% CI: -6.81, -3.15; p < 0.001) and Attention (beta: -6.81; 95% CI: -8.60, -5.03; p < 0.001) RBANS domains. Conclusions Regular use of definite anticholinergic medications and benzodiazepines, but not potential anticholinergics or "Z-drugs", was associated with poorer overall and domain-specific neuropsychological performance in older adults.