Anticholinergics may cause cognitive impairment
Anticholinergic drugs, commonly taken by the elderly, may cause cognitive impairment when taken for 60 days or more. Even drugs with weak anticholinergic effects can have a negative impact on the brain if multiple types are taken for 90 days or more. Anticholinergic drugs are often taken as sleep aids or for bladder leakage and are over-the-counter in many cases.
http://www.sciencedaily.com/releases/2013/05/130507124809.htm