Why has my mother started hiding odd things?

This type of behavior is common with Alzheimer's disease. You mention paranoia, which is what it is. I know one woman whose mother kept hiding her hearing aids. They kept finding them in lamps, etc. The mother was afraid someone would steal them. I'd have your mother evaluated by a specialist. If you can't tell the doctor about this behavior in front of your mother, drop a note ahead of time, so that he or she can have a head start. There are other medical problems that can mimic dementia, but since you saw that your grandmother did the same thing, I would suspect some type of dementia.
Take care,
Carol

I feel your pain and frustration! My mom has been doing this for a few years. Even when it's something harmless that she's hiding, it's maddening. But it gets serious when it's the checkbook, mail, my dad's hearing aids, the TV remote, the 1099's for their taxes, etc. Now she is also "packing" all the time to move (she just moved 4 months ago to a Memory Care Unit and will not be moving again, but I can't convince her of that.) So things are always stashed in the trashcans, trashbags, dirty clothes hamper, etc. because she thinks she's moving the next day or today. Now, I receive all of her mail, pay all of her bills. She has a little "fun money" check book and I keep minimum of money in there for her. She can't go to the bank unless I take her anyway. She hides her purse constantly and then no one can find it, which is a problem, since she wants to carry it everywhere with her, everytime she leaves her apt. at Memory Care...to go to the dining room, to an activity, etc. I redid her address book for her (she & Dad had 4 of them over the decades because they never threw any away). I consolidated all 4 address books, called people to see which phone nos were even still connected, who was dead by now, etc. She hid the new phone book immediately after I took it to her. I spend every visit looking for things. At least she only lives in one room now, so less places to look. The staff are very nice where she lives and will help her look for things, too. And yes, I am also afraid of doing this myself someday. Good luck to you!

My husband has a different form of dementia that doesn't seem to include hiding objects, so I have no personal experience with this. But I think the book "Creating Moments of Joy," by Jolene Brackey displays a very helpful and compassionate attitude about this issue. Perhaps you'd find it helpful.