Participants in the study who were taking drugs with a combined score of more than 5 also showed cognitive decline - they scored more than 4 % lower in cognitive function tests compared with those who were taking no anticholinergic drugs .
Protect yourself : if you 're over age 65 , you 're more vulnerable to side effects from diphenhydramine , an anticholinergic used in many over-the-counter sleep aids and allergy drugs .