Morgan is diabetic. Along with excessive drinking there is excessive urination. Morgan never didn't use the litterbox, but he would urinate so often that it was like cleaning cement out of it. Those were the signs my vet had told me to watch for because Morgan is such a big kitty. They tend to have a higher likelyhood of being diabetic. Morgan's diabetes is controlled by his low carb food. Hopefully Barney will start looking and feeling better soon with all the love he's receiving from you wonderful people!