Can cats gain senile dementia around 11-12 years old?

My cat seems to be meowing and continuously hissing, running around the house and just generally crazy, we have taken her to the vet and he says there’s nothing phsycially wrong with her. The only suggestion he could give was that she might be being posioned from fertillisers in neighbouring gardens. Anyway im just wondering if cats can gain dementia at around 11??

Filed Under: Health and Ill