Is this a sign of something worse than clinical depression??

Okay, so this has been bothering me for years, and I'm just wondering if this is something anyone else has experienced in themselves or someone they know.

My mom has clinical depression (though this is very likely only a small part of the story), and when we're in a room together, sometimes she'll just all of a sudden start talking to herself. But she's not talking "to herself". I realize, by the content of what she's saying, it's usually people who aren't even there. I consider myself someone who has a lot of tolerance for weird behavior. Like, I'll often spend hours walking around, just thinking to myself, trying to figure things out in my head. But I just find it weird she has to say this OUT LOUD.

Part of me is wondering, if maybe she "hears" people out loud, and then responds? I KNOW she's not schizophrenic - but it seems now, and occasionally in the past, that she has lost contact with reality a bit. This also seems to go along with her stress level - basically, when she's having a problem with someone, she'll start "talking" to them. This happened a lot when I was little, then stopped for several years, and now has recently started happening again. So I really think it's more than an "odd habit".

She's also an alcoholic and usually does this when drinking, but I have seen her do this completely sober too. It kind of scares me, only because I'm trying to think about how these "other people" manifest themselves in her head.

It's like... on a day where she's not completely stressed, she can't even talk about her problems, but when she is (or drunk) she can't even contain herself. Anyone know what this could be?

Yes, it is definitely something more than depression. Can you get her to talk to a doctor about it? Or can you contact her doctor and tell him/her about it?

Also, how do you know she's not schizophrenic?

I know she's not schizophrenic because she has a good job and is (barely) able to function, this is the only schizo-like thing she does. Except she refuses to see a doctor because she says her employer will find out and they'll fire her... I'm not sure if she actually THINKS this or is just making excuses. Either way, I do have a psychiatrist I see, and I might mention this the next time I see him...

The one thing my dad and I have suspected for a while now is borderline personality disorder. She can be very manipulative and hostile sometimes, like she thinks you're either with her or against her, and that she can "change" other people... and I'm afraid, because personality disorders are a constant. But I recently found out theres a "depression with psychotic features" and I'm wondering if this is it, because it honestly seems more like she has "episodes", sort of like I do (I have bipolar, and we strongly suspect her sister did, as well as her father... so there is a family history here...)