Why Self-Reports of Happiness and Sadness May Not Necessarily Contradict Bipolarity: A Psychometric Review and Proposal

It is assumed that bipolarity in happiness and sadness requires mutual exclusion. However, we present psychometric research to show how coendorsements of happiness and sadness do not necessarily constitute evidence against bipolarity. Because individuals have a tendency to endorse emotion terms close to their current state, individuals whose current state is close to the middle of a bipolar continuum would report both happiness and sadness, despite their current state being best represented by a single point. As such, endorsements of happiness and sadness are theoretically expected when individuals' current state is in the middle of the continuum. Bipolarity however would be violated if endorsements of extreme levels of happiness and sadness can be demonstrated, which has yet to be shown.