Scientists have long found a possible link between anticholinergic drugs and an increased risk of dementia. A study published in the journal JAMA Internal Medicine on Monday suggests that the link is strongest for certain classes of anticholinergic drugs - particularly antidepressants such as paroxetine or amitriptyline, bladder antimuscarinics such as oxybutynin or tolterodine, antipsychotics such as chlorpromazine or olanzapine and antiepileptic drugs such as oxcarbazepine or carbamazepine. Researchers wrote in the study that "there was nearly a 50% increased odds of dementia" associated with a total anticholinergic exposure of more than 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, compared with no exposure. The researchers found only an association between anticholinergic drugs and dementia risk, not a causal relationship. "However, if this association is causal, the population-attributable fractions indicate that around 10% of dementia diagnoses are attributable to anticholinergic drug exposure, which would equate, for example, to around 20,000 of the 209,600 new cases of dementia per year in the United Kingdom," the researchers wrote in the study. It has been well known that anticholinergic agents and confusion or memory issues are linked, but the new study investigated this association over a long period of time, said Dr. Douglas Scharre ... at the Ohio State University Wexner Medical Center.