A boy is highly confident one day and the next day scared, timid and shy.
A girl is emotional one day and emotionless the next.
Is there a term for a drastic switching of emotions? A term for the switching to practically opposite emotions?
EDIT: Just to clarify the emotional changes are not rapid, and are permanent. This rules out bi-polar, because bi-polar involves multiple periods of change. I'm looking for a work to demonstrate the steepness or contrasts of change, but having no relationship to the speed of change.
Over a course of 3 years a once quiet boy become the spokesmen of the school.