I agree, people always think about sometihng, talk in their mind - for example driving down the road, thining "what a beautiful morning, or .. no no no, I am running late for work, hurry hurry. Or when people have road rage - who do they talk to - to themselves too
I wanted to add an interesting thing, while I was on antidepressant, I was also added olanzapine (zyprexa) because back in the day, and even today, for some strange reason it is thought that antipsychotics help people who experience depressive disorders. It actually made me worse; restless, and I had the opposite reaction, I would drive in my car and start singing to the music, go off talking like - "beautiful song, la la la," ..
On the other hand, at times, now, that I do not take that kind of medication, but if I take antidepressant, (which can cause psychotic type of reaction by itself)
I find it natural, to express some thought vocally, especially if I recall something embarrassing from the past, it could provoke me to say, "how stupid". I think it's good not to hold in feelings, writing helps.
Like a flash back moments, if thinks that I once lived through, this dis-inhibition by antidepressant and even antipsychotics can have very same effect. You simple talk out something that you think.
On the other hand, talking for an hour in front of a mirror, I think can be a coping mechanism, past trauma?
Even kids create imaginary friends.
So it is important to exactly see what's going on, what promotes this - what happens before you start doing this, what happens when you do it, and what happens after. It makes natural sense to feel a relief after this, like unexpressed feelings, when you put them on a paper.
Perhaps you can record yourself doing it and analyze it.
The labels of "am I schizophrenic do no good", asking, "do I have some symptoms of schizophrenia" might be better, I think.
Wishing best,
Ed