Objective: To investigate whether cognitive adverse effects occurring immediately after taking anticholinergics are related to the development of long-term dementia and to interpret this from the perspective of cognitive reserve.
Background: Anticholinergics used for tremor and levodopa-induced dyskinesia in Parkinson’s disease are known to be associated with cognitive decline after long-term exposure. However, the association between cognitive adverse effects of anticholinergics and the development of long-term dementia in Parkinson’s disease has not yet been revealed.
Method: We performed a retrospective chart review of 209 PD patients first prescribed anticholinergic medication at the Seoul National University Hospital between January 1, 2011 and December 31, 2020. Data on anticholinergic medication history, adverse effects were collected, and then long-term dementia incidence rates were compared in each group who discontinued medication due to cognitive and non-cognitive adverse effects.
Results: A total of 155 patients took trihexyphenidyl or benztropine or amantadine were included for analysis. Of these, 93 patients discontinued the medication due to adverse effects or ineffectiveness, and cognitive adverse effects such as memory loss and hallucination occurred in 12 patients. The remaining 81 patients reported non-cognitive adverse effects such as dry mouth, voiding difficulty, and dizziness. The proportion of patients diagnosed with dementia during the follow-up period after medication discontinuation was higher in the cognitive adverse effect group than in the non-cognitive adverse effect group, but there was no statistically significant difference (16.7% vs. 9.9%, p = 0.479).
Conclusion: There was no association between cognitive adverse effects of anticholinergic medication and the development of long-term dementia in Parkinson’s disease, and the cognitive reserve hypothesis could not be confirmed. However, it is thought that further research using tools to evaluate cognitive reserve with a sufficient follow-up period is needed.
To cite this abstract in AMA style:
SH. Ha, BR. Jin, SY. Kim, SM. Lee, JH. Shin, HJ. Kim. Association between cognitive adverse effects of anticholinergic medication and development of long-term dementia in Parkinson’s disease [abstract]. Mov Disord. 2025; 40 (suppl 1). https://www.mdsabstracts.org/abstract/association-between-cognitive-adverse-effects-of-anticholinergic-medication-and-development-of-long-term-dementia-in-parkinsons-disease/. Accessed November 20, 2025.« Back to 2025 International Congress
MDS Abstracts - https://www.mdsabstracts.org/abstract/association-between-cognitive-adverse-effects-of-anticholinergic-medication-and-development-of-long-term-dementia-in-parkinsons-disease/