I don't believe in a true self, or "real" personality, anymore. There are too many circumstances and situations that drastically change behavior that we will never know or need to know who we are in a vacuum. I'm a different person manic, depressed, mixed, stable on meds, before developing symptoms, in physical pain, hungry, sleepy, energized, at work, at home, in the grocery store, on a hiking trail, etc that it's not fair to say one of them is the real me and the rest aren't.
On meds that work, you are the you that is stable. Off meds you are the you that isn't. One isn't any more real or true than the other, just different circumstances.