Does dementia affect older people, and why does it occur?

Hi doctor,

My mother is in her 60s and has a tube in her heart. She is on medication for diabetes, cholesterol, and blood pressure, and everything is under control. However, she has had undiagnosed repetition and forgetfulness for the past six years. Also, she does not sleep well and usually stays up late till dawn and wakes up late afternoon. For the past two months, I can see that her memory has been getting worse. She recalls things that happened in the past, but not what she did five minutes ago, an hour ago, or the day before. So I consulted with a doctor. He performed an MRI scan, and the results were negative. It was said that everything is functioning well and that there is no sign of dementia. He even did that test by asking her about dates, family names, and friends, and she could answer all of them. She has been battling depression and anxiety. She was not at all like she had even lost patience.

An incident occurred. I have been out of the country for medical treatment for two months now, which I believe has exacerbated her worry. I call her every day, but today she forgot where I was and started crying. However, after a few discussions with her, she seemed normal again. So we hung up the phone. And I called her back again ten minutes later. She said she was fine now, but she again forgot that I was away for medical treatment and asked me to come and meet her tomorrow. Why does this happen? Is something affecting her memory? During the past few months, her brain was like a coma, and she could not remember anything, but now she is better. Was her brain starting all over, forgetting what had happened in the past two months? Could her anxiety and depression episode or something have caused this? Or is it dementia?

Hi doctor,

Thank you for the reply.

Is it dementia or dementia-like symptoms caused by depression or any medications? Is this condition reversible? Also, can stress and lack of sleep make it worse? I cannot take her to a psychiatrist for two months, so what should I do in the meantime? Also, how many years does it take for someone to forget completely? Because she has been like this for seven years now.