To do so, they used QResearch, a large database of anonymized health records, to examine nearly 285,000 adults in the U.K., aged 55 and older, between 2004 and 2016.
The team then reviewed each subject’s prescription records to determine their exposure to anticholinergics, which can include antidepressants, bladder antimuscarinics, antipsychotics and antiepileptic drugs.
After analyzing the results, they found those on anticholinergic medications had almost a 50% increased chance of developing dementia, compared to those who didn’t have prescriptions for anticholinergic drugs. The risk was only associated with 1,095 daily doses within a 10-year period, which is equivalent to an older adult taking a strong anticholinergic medication daily for at least three years.
"The study is important because it strengthens a growing body of evidence showing that strong anticholinergic drugs have long term associations with dementia risk," coauthor Carol Coupland told CNN. "It also highlights which types of anticholinergic drugs have the strongest associations. This is important information for physicians to know when considering whether to prescribe these drugs."
Although the authors said “no firm conclusions can be drawn about whether these anticholinergic drugs cause dementia,” they hope their findings can help professionals better understand the disease. They also advised patients to not stop taking their medications until consulting with their doctor.
As for antihistamines, skeletal muscle relaxants, gastrointestinal antispasmodics, antiarrhythmics, or antimuscarinic bronchodilators, the scientists noted there were no significant dementia risks associated with them.
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