I have to say, it definitely made a difference.
When I ran out, I waited for the cog fog
to come back so I could tell whether it was the
Aricept - and it did. So I got a prescription, and took it for five months. Each time I ran out, I waited until the fog returned, then got my script refilled. When the fog stayed away, I stopped taking it. I don't know how long it would have taken without the Aricept - but it really seemed to help clear the fog.