I did want to get some additional information from you, but, I didn't want you to wait any longer for an answer.
Cats peeing in inappropriate places is a very common problem for cat-parents and it has many causes. I'm very glad that you had her checked out a couple of weeks ago and all was well, but please keep in mind that there still may be an underlying medical problem causing her inappropriate elimination. It could be coincidental, but if a urinalysis and urine culture were not done at her visit, it's possible she could have a urinary tract infection, bladder infection, kidney issue or interstitial cystitis. Interstitial cystitis is an inflammation in the bladder but there is no infection present. It is often caused by stress. Here is more information:
If you feel the catio incident is what started this problem, then she is stressed and anxious and although it sounds lovely, she's probably afraid you'll put her in there, again and for some reason, she feels afraid in there for some reason.
If you have only 1 litterbox in the house, add one in a different part of the house. Make sure both litterboxes are uncovered and use an unscented litter. You can also add 'Cat Attract', a kitty litter additive to her regular litter; this contains herbal attractants that encourage use of the litterbox.
Also, get some Feliway spray and plug-in diffusers. These contain cat-calming pheromones that are only detected by cats and have no scent to humans. Put a plug-in in your bedroom, and put another one in a room where she spends the most time, like the livingroom or den, etc. Here is more information:
There are two other, over the counter, oral calming products that you could try, but only choose one; they cannot be given simultaneously, but using one of them along with the Feliway, won't be a problem:
Rescue Remedy for Pets
It's also important that you wash your bedding in detergent with an enzyme based additive to completely remove the stain/odor of the cat urine:
This is important, so she doesn't smell the scent of where she's gone before and want to return there. After washing your linen lightly spray with Feliway; this should fool her into thinking she already marked there. Also, keep your bedroom door closed all the time, so she has no access to your bed and if you can't keep the door closed all the time, put a plastic tarp over your bed, with strips of double-stick tape all over it, because cats don't like 'sticky' under their paws.
I understand that you wanted to enrich her environment with the catio, but since it was a problem, you can get her some new toys, divide them into groups and switch them out every few days, so she feels like she's getting 'new' ones, each time. This list is great and includes a cat dvd:
Also, make sure she has a tall cat tree or kitty condo with different levels and 'hidey' holes, for playing, sleeping and scratching (these are usually covered in carpet material).
Try spending more time with her, have play sessions and cuddle sessions and speak gently to her all the time, to reassure her.
I only like to recommend a prescription medication as a last resort, but discuss this with your vet and even though there are many different medications for this type of problem, I find that Clomicalm is well-recommended.
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I will always be here if you need additional information; just click 'reply' and I will be glad to continue our conversation.