Carl Jung has written extensively about these "parts" of the mind. His process of "individuation", which is modeled on the alchemical spagyric -- take apart and reintegrate -- process, can be used by people today in order to achieve similar results.

Moreover, what you describe can also be found in western mystery schools and traditions that go back hundreds of years. Terms such as "knowledge and conversation with the holy guardian angel", "crossing the abyss", "ego death", "ascending the Tree of Life" refer to profound, iconoclastic experiences that can forever shatter one's assumption of being a monad in space-time. Realizing that in one's mind exist various superintelligences, normally inaccessible, with their own motives and goals, can be quite distressing to say the least.