The adverse effects of long-term exposure to anticholinergics among people with intellectual disabilities: a scoping review

Background: Older adults with intellectual disability are exposed to a higher anticholinergic burden compared to general older adults. This is due to a higher rate of both mental and neurological disorders among people with intellectual disability. The use of medications with a high anticholinergic burden is associated with adverse effects including daytime dozing, constipation and higher dependence level in the Barthel index for measuring activities of daily living. This scoping review aims to map and examine the existing research on physical and cognitive adverse effects associated with the long-term impact of anticholinergics among people with intellectual disabilities. Methods: The search was conducted in: PubMed, Cochrane library, EMBASE, Medline, Science Direct, CINAHL Complete and PsycINFO. Preliminary studies, grey literature, and conference papers were searched in related electronic databases. The search terms included terms related to ‘anticholinergic’, ‘long-term exposure’, ‘intellectual disability’ and ‘adverse drug reaction’ with Boolean operator ‘and’. Studies with at least three months’ exposure to anticholinergics were included. The search was restricted to research papers on people with intellectual disability aged 40 or over and publication in the English language only. Initially, it was conducted in May and June 2021 and covered the publication period between 1970 and 2021. It was re-run in October 2021. Results: The conducted search provided 509 records of publications and grey literature. Duplicates were removed using EndNote 20 and resulted in 432 remaining records. Then, 426 further records were excluded because they were deemed irrelevant, or non-longitudinal studies or conducted on different populations. Only six full articles were retrieved to assess their eligibility and all were excluded due to different study populations. This resulted in no studies meeting the stated inclusion criteria. Conclusions: Further research is urgently required to examine the long-term adverse effects associated with higher anticholinergic scores among older people with intellectual disability.