Best anti anxiety for cats?

My older kitty seems to work herself up into a panic attack quite often. Usually in the mornings. Sometimes petting her wont soothe her and i wind up letting my dog back in because she seems to calm down when hes inside. But every once in a while that doesnt work and shes just meowing and pacing. I know its not pain. Thats been adressed. The only thing i can think of is maybe in the mornings her mind isnt quite working the way it should? The vet said she has a little teeny bit of dementia. I just want to find something to maybe put in her food in the morning so she can feel more relaxed until she can get her gripping again.