Formerly very social 88 year old Mom's refused to see friends, or participate in activities in her assisted living facility for the last year. And lately, her "trips down memory lane" are only negative (remembering slights of decades ago, revisiting old grievances and revealing upsetting family secrets). Any tips on how to help her? It's gotten to the point where I'M depressed after every visit.
As Alva suggests in her response: Life can be sad sometimes, so it's o.k. to be sad sometimes. Dementia, particularly Alzheimer's, can ultimately leave only the most basic mental functions. The things that happened in the past that created the most emotion are the things we may be most likely to remember, good or bad.
From my personal experience with loved ones and anti-depressants, I can safely say that there is no "magic pill" out there that works for everyone. It is ALWAYS a trial-and-error process for finding the right medication and dose that helps, and there are ALWAYS side effects (even if mild) to any anti-depressant.
I know it's easy for me to say, but try not to let her melancholy affect you. During your visits you might bring things that create positive memories: photos from that trip to Disneyland years ago, uplifting music she's always liked, etc.
My MIL lived to 96 and spent 15 yrs in a NH and would frequently lash out. When my wife went to visit, she would change the TV from Bonanza to a show about gardening because my wife knew that my MIL loved to spend time tending to her garden for 60 of her 96 yrs. My MIL would be screaming "Kill them, kill them!!!" at the TV during Bonanza, but became interested and calm during the gardening shows.
The point is... Find some happy memories to tap into before you go straight to medication. That being said, an appointment with a geriatric psychologist is probably still a good idea. He/she would hopefully have even more suggestions for you.
Good luck!