This study might not be the final word, but as someone who has taken quite a few antihistamine pills over the years, I was certainly a little concerned upon seeing hay-fever mentioned. I'm glad to see that the medication I took is a little different from the ones in the study.
From the article:
> A study has linked commonly used medicines, including over-the-counter treatments for conditions such as insomnia and hay-fever, to dementia.
> All of the types of medication in question are drugs that have an "anticholinergic" effect.
From Wikipedia: [1]
> Cetirizine /sɛˈtɪrɨziːn/ (trade names Zyrtec, Reactine).
> Unlike many other antihistamines, Cetirizine does not exhibit anticholinergic properties.