Q. My cat won't use the litter box, increased appetite and thirst, excessive need of wanting to be held, which is extremely unusual.
LINDSEY EDWARDS MVB, BSC, IVCA
A. You do not mention an age but an increased appetite and thirst in cats would often be indicative of a hormonal disease such as diabetes or thyroid disease. You do not say whether she is unable to urinate/defecate or unwilling to use the tray but I would be concerned of an underlying pain or discomfort preventing this and also making her in need of more reassurance. Anxiety from bullying by stray cats can also cause behavior and training issues