Hi, Trua. Welcome to PsychCentral.

I think having a pet is a good influence on the bipolar individual for two reasons. (There may be more, but I can only come up with two right now.) First: there's the affection, simple as that. The love from your pet will help you feel better when you're down, even if it doesn't make you completely better. Second: pets need routines. Your cat would need to be fed at the same time (more or less) every day. We also benefit from a regular schedule, so having that pet means I have to get up out of bed every morning even if I'd rather sleep all day. To sum up, I would say a pet is a positive burden.