Since you asked, I'll copy my post from elsewhere in this thread.

I have bipolar disorder. I also am an avid experimenter with messing around with my mind state, to figure out what is the best way of coping with my illness.

All of this is anecdotal, and I highly don't recommend doing anything I've done based off of what I've done.

Before my major episode which resulted in a diagnoses (primarily caused by smoking marijuana and having several bad trips), I wouldn't notice my inner dialogue too much. I was aware it occurred, but it was mostly a background process. Sometimes while trying to sleep I would hear people I know calling my name with the sound of their voices. I even made a post on yahoo answers asking what caused that. So I am capable of replicating voices in my head that aren't mine, and I believe I've been capable of doing that for awhile. This ability actually makes it somewhat easier to mimick a person or culture's accent. During my episodes I became more aware of my inner voice, and I tried to control it. I realized my inner voice sounded very frantic and it would go at a very fast pace. I decided that was no good, and I had to calm it down. So I would consciously be aware of what my inner voice said while I was thinking. I would slow it down, think deliberately and calmly. No surprise, my speaking voice became much slower and thoughtful, to the point of sounding robotic. If you've heard of the book think fast and slow, I did more of the slower thinking. I haven't read the book, but I get the idea. I think it's a good analogy, but I don't believe it covers everything. Just a good model. Anyway, I became a slower, more deliberate thinker. Prior, I would blurt things out without speaking, but afterward I became much more conscientious of what I say. I guess you could say I had a filter afterward. My logic skills became much more developed, as I studied things I didn't have time for before the transition. I became more socially awkward and more of a day dreamer, constantly thinking in my head and ignoring my surroundings.

I'm experimenting on reversing the trend. Cutting out the deliberate thinking, and allowing my inner voice to go at its natural pace. I don't subvocalize as much anymore, and my thoughts go much faster. I change topics in my head much more quickly, instead of ruminating over the same topic for dozens of minutes. Much more natural in human interaction, as I'm not over analyzing the situation. I think still think of fairly complex topics and understand them, however, I see some things I wouldn't see with deliberate thinking, and miss out on other things that I would've saw with deliberate thinking.

I guess the lesson I've learned, for me, is moderation. Aristotle's golden mean. I don't mean to cut sub vocalization out entirely, as it would be incredibly difficult, perhaps, to study what I'm studying without any of it. However, I'm trying to find the right mixture that utilizes the maximum benefits.

For me I've had significant changes on my beliefs, attitude, and thoughts based on how I effected my way of thinking. This leads me to believe that even little things like tweaking the settings of your inner voice can lead to fairly high changes. To the outside world I make come across as the enigma of a person with Bipolar Disorder, changing often. However, to me I'm trying new things out, and when you experiment you get different results.

Also, for those wondering. The reason why I deliberately changed the pace and tone of my inner voice is that when I was diagnosed Bipolar, I came to the conclusion that mania is the worst thing that can happen. Traditionally, professionals will try their best to make sure that you do not become manic. Manic episodes tend to make the condition much worse. Hence, the natural conclusion, slow down your thoughts - less mania. It worked in terrific fashion. I use to be prone to mania and anger. Guess what my major problem is now? Depression. It worked a bit too well.

It's amazing to see how people think so differently, based on responses here. It goes to show we really aren't all the same. There's vast differences between people, and how we think surely is at least one factor.