What could be the cause of short term memory loss, with a poor appetite, depression and anxiety. An example of her memory loss would be, I could call her and tell her I will be over in a couple hours and when I arrive she has forgotten our conversation and that I was coming over. This is for my 70 year old friend. She went to doctors. They ran blood tests, waiting for MRI. The Doctor said it was not dementia because it came on so quick. Another odd thing is she has always drank soda and coffee. She hated water and only drank maybe a cup a day. Now she doesn't like soda or coffee and only drinks water.