Hello & welcome, I am Dr. B, a licensed veterinarian and I would like to help you with your wee one today.
First, as I am sure you can appreciate, a lapse in litter box manners can be caused by a range of reasons. Urinating out of the appropriate spot in a cat is like a message (since cat’s don’t do email) that something is amiss. And we have to channel our inner Sherlock Holmes to decipher their message and address the underlying trigger for their behaviour. Determining what has set them off can sometimes be difficult but generally speaking, we see this behavior arise with health issues, territorial insecurity, and stress/anxiety. And based on your history, the intermittent behavior, and her having done this since you took her on; I'd be most concerned about behavioral causes as opposed to medical ones here.
Specifically, Posh's behavior does raise concerns about territorial insecurity and general stres/anxiety. Especially since she has already had a few homes in her short life, may not have a sense of what a permanent home is, and has previously lived with another cat (which we don't know if this arose when she was living that cat, should it have made her feel like she needed to claim a spot by urinating). In any case, at this stage, we need to be focusing on reducing stress, triggers for urination (including any odor from where she has gone before), and continuing positive re-enforcement when she uses the box.
Further to your praise (since negative responses to the behavior isn't something she will understand and will likely just cause further upset for her), we want to consider trying her with a de-stressing treatment. Now there are a range of tools we can use to help provide a general peaceful environment for our cats. Often we will use Feliway, (also known as Comfort Zone in the pet stores) which is a synthetic cat pheromone that helps to relieve stress, promote relaxation, and help the stressed cat cope with the situation. This can be used as a spray or a plug-in diffuser (ideally used wherever the cats hang out most). There is also a diet on the market called Calm by Royal Canin. This contains a number of supplements that have been found to provide stress relief to cats. As well, there are nutritional supplements available from the vets, like Kalmaid (LINK) or Zylkene , that we often use to soothe anxious cats. As well, there are treats like Composure (LINK) and even a Bach Flower Remedy (LINK) for cats (though not as well tolerated as the other agents and isn’t as feline specific as the other de-stress agents are). And since these are not drugs persay, it is safe to use them in combination as needed to help her settle and not feel this drive to claim a piece of your home as hers.
Further to this, if she is targeting furniture in a specific room, you may want to consider putting a litter box (for the short term) near where she is going. This will give her the option to go in an appropriate place. And with this (and her other box) you can even use a 'litter attractant' to remind her where she should be going (LINK) and make her aware of any new boxes in that room.
Furthermore, at the same time, you need to make sure that you are taking steps to discourage her associating the carpet/furniture/non litterbox places with being somewhere she can go, by making sure the areas are cleaned afterwards. I would advise using an enzymatic odour neutralizing cleaner (LINK1 LINK 2) wherever she has urinated because while normal cleaners will eliminate the smell to us, she may still be able to smell her own scent and thus choose to go there again. Her scent will be the red flag that its 'ok to pee here'. To make sure you get everywhere she has been, you can use a black light to illuminate any areas that she has urinated on (example).
Overall, Posh's inappropriate urination signs are quite suspicious of a an insecure cat struggling to cope with a new settled life. Therefore, I would advise the above steps helping her to settle and reduce her need for marking/claiming the furniture. If you try the above and are struggling (since we do have the risk of this being a habit after so much time doing so), then you may consider following up with your vet to discuss drug management of this condition. There are drugs that can be used in environmental modification resistant cats that can decrease feline arousal and thus dampen their drive for anxious territory marking. These can be short term and long term treatments depending on the cat. Often it doesn’t have to get to that point and alteration of the environment can settle them down. It will just again be a case of trying to reduce her anxiety and help her understand that there is no threat that is requiring to mark the house and furniture as hers.
I hope this information is helpful.
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All the best,
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