[jdm]

In all honesty, I share some similarities with this individual. While in high school, I was diagnosed with OCD and panic disorder. Talking to oneself (out loud, albeit quietly) could certainly be but one primary facet of OCD.

I'm doubting bipolar or schizophrenia, although without more information it's hard to say.

[najida]

Well,
I've heard that Bipolar and Schizo-effective disorder can look like Schizophrenia at first.

I don't know, I just know that what seems bad to you is pure hell for the person living inside their head.