Is the relationship between frontal EEG alpha asymmetry and depression mediated by implicit or explicit self-esteem?

A robust physiological finding is a higher relative left sided activity in the prefrontal cortex during the experience of positive approach related emotions and a higher relative right sided activity during the experience of negative withdrawal related emotions. Since self-esteem can be conceptualized within a framework of approach/withdrawal tendencies, the present study aimed at investigating if the relation between frontal EEG alpha asymmetry and depressive symptoms is mediated by implicit or explicit self-esteem. Self-esteem was measured by questionnaires (explicit) and in an indirect way (implicit). The mediation analyses showed that only explicit self-esteem acted as a partial mediator in the path from EEG alpha asymmetry to depression.