For the millions of adults living with early cognitive decline, the medications prescribed for other health conditions may quietly compound the very problem being overlooked. A forthcoming Norwegian registry study targets a clinically underexplored window: the twelve months before a formal diagnosis of mild cognitive impairment or dementia, when polypharmacy and cognitively harmful drugs are already common but rarely scrutinized.
The research protocol — a registered report design published in PLOS ONE — outlines a retrospective cohort study linking three national Norwegian registries: the Registry of Persons Assessed for Cognitive Symptoms, the Prescribed Drug Registry, and the Norwegian Patient Registry. The full diagnostic decade spans 2014 to 2024, capturing all adults assessed in specialist outpatient clinics during that period. The team will quantify twelve-month prevalence of polypharmacy and use of potentially inappropriate medications specifically harmful to cognition (PIMcog), then model demographic and clinical factors that predict PIMcog exposure.
This is a protocol publication, not a results paper — meaning the findings remain pending. Nevertheless, its design merits attention. The existing literature already suggests polypharmacy affects roughly half of individuals with MCI or dementia, and that PIM exposure escalates as total medication burden grows. Anticholinergic drugs, benzodiazepines, and certain antipsychotics — all common PIMs in older adults — are associated with accelerated cognitive decline and elevated fall and delirium risk. By focusing on the pre-diagnostic window specifically, this study may reveal whether problematic prescribing precedes or contributes to clinical recognition of impairment. Methodologically, registry linkage in Norway benefits from near-complete population coverage and high-quality dispensing data, lending the eventual findings substantial statistical power. The primary limitation is observational design: associations between PIMcog use and cognitive status cannot establish causality. Clinicians and pharmacists working with aging populations should watch for the results.