Why does my 92-year-old mother start to cry uncontrollably for no reason whatsoever?

sounds like a bipolar episode to me. my mother has bouts of absolute despondancy. the hospice nurse usedta think something was upsetting her but she now attributes it to bipolar cycling. a dementia patient almost always developes an obssessive disorder too. my mother straightens the blanket on her bed every time she goes thru the bedroom. the blanket was already flawless is what im sayin..

People who have had strokes often cry for no reason. I don't know if it's a brain thing or an emotional thing. (I know this from working at a speech and hearing clinic where many stroke patients came to work on their speech.) It sounds lie medical involvement with the other symptoms. Perhaps she should have a CAT scan? I'm not a doctor, but...

correction to sentence:: In other words, get her to a doctor now.

I have a friend who was diagnosed with MS . Crying and/or laughing excessively without cause can be a symptom of MS.
Also, Alzheimers, neurological problems.
I other words, get her to a doctor now.
Let us know what is going on with your mom.
Prayers and thoughts are with you.

I would get her to a Dr ASAP, she may have a low grade infection if she gets very warm. It may be physical instead of mental.