Does she have an official diagnosis of sorts?

Does she recognise any of her behaviours as being an issue?

It's difficult to get help if she doesn't see a problem and isn't wanting to get assistance.

If she thinks there's a miracle pill - well, there is for depression. It's not a miracle pill, but it can help alleviate depressive symptoms, in some.

Perhaps encourage her to go to your family doctor and discuss her depressive symptoms to see what, if anything, can be done.