What Causes Nervousness And Anxiety In An Elderly Person While On Citalopram?

My sister is 77 yo, has a heart condition and rheumatoid arthritis, has had cancer, has had all her teeth pulled prep to getting dentures, but she hasn t been able to eat solid food for several months, and complains of pain almost all the time. She has back pain most of the time and can hardly walk. She has very little energy and tries to do things but wears out after 15-30 minutes. She s been depressed and I had her talk to her doctor who prescribed citalopram for her, which she did not want to take because that s one more medication, and she has a lot of medications to take every day. Unfortunately I do not have a list of those meds. She is still depressed and crying everyday. She complains also of being nervous or anxious all the time, and I quote Everything is going wrong. It has recently occurred to me that this crying, nervousness and sadness may have to do with dementia or Alzheimer s. What do you think and how is this tested for?