Prevalence and factors associated with polypharmacy in Victorian adults with intellectual disability.
One in five Victorian adults with ID take five-plus medicines, and newer data say it is closer to two in five—so flag anyone at that line for a review.
01Research in Context
What this study did
Haider et al. (2014) mailed surveys to Victorian adults with intellectual disability. They asked about every medicine the person took. They wanted to know how many people use five or more drugs at once. This is called polypharmacy.
What they found
One in five adults with ID took five-plus medicines. Older adults and people with more health problems had the highest counts. More doctor visits also meant more pills.
How this fits with other research
Heald et al. (2020) asked the same question with a bigger sample and got 38%. The jump from 21% to 38% looks like a contradiction, but it is not. The 2020 team counted every person on the state ID register, while the 2014 study used a smaller volunteer group. The larger, stricter count simply updates the picture.
Higgins et al. (2021) took the same group and checked for drug-drug interactions. They found each extra pill raises the risk of harmful combos. Agiovlasitis et al. (2025) in the UK added a brief staff-training program that doubled antipsychotic dose reductions at six months, showing polypharmacy can be safely cut.
Why it matters
If you support adults with ID, treat five medicines as a red flag. Ask for a medicine review at every plan meeting. Team up with doctors and pharmacists to check for drug interactions and to see if any pill can be stopped or swapped for behavior-analytic support. Quick staff training, like the UK SPECTROM model, can spark real dose cuts within months.
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02At a glance
03Original abstract
Although polypharmacy is a medication safety concern leading to increased risk of non-adherence, adverse drug reaction and drug-drug interactions, polypharmacy and associated risk factors has rarely been investigated involving people with ID at a population level. The purpose of this paper is to analyze the prevalence of polypharmacy and to evaluate the role of different factors associated with polypharmacy in a state-wide representative population of adults with ID. In a population-based survey in Victoria, Australia, 897 people with ID 18 years of age or older were selected by simple random sampling. The data were collected from proxy respondents on behalf of people with ID. Polypharmacy was defined as the concomitant use of five or more medications. The data were weighted to reflect the age/sex/geographic distribution of the population. Results revealed that more than 76% of adults with ID had used prescribed medicine and about 21% were exposed to polypharmacy in the last two weeks. In both univariate and multivariate analyses, polypharmacy was significantly associated with older age, unemployment and inability to get help from family and friends if needed. After controlling for age, sex and severity of intellectual disability, polypharmacy was associated with having a blood pressure, blood cholesterol and blood glucose level check. Polypharmacy was also associated with a greater number of visits to general practitioners, fair or poor reported health status and inability to walk unaided. Subjects with epilepsy, diabetes, stroke, osteoporosis and cancer had a higher probability of polypharmacy. None of the disease inducing behaviors was associated with polypharmacy. This study highlights the need that medication should be regularly reviewed overall in ID population and particularly when polypharmacy exists.
Research in developmental disabilities, 2014 · doi:10.1016/j.ridd.2014.07.060