A slow wave investigation of working memory biases in mood disorders

Mood-congruent working memory biases were examined in a delayed matching to sample paradigm using the slow wave (SW) event-related brain potential (ER P) component. Mood-congruent working memory biases, indexed by SW amplitude s, were demonstrated among individuals experiencing a major depressive epis ode (MDE) and nondepressed controls but not individuals with dysthymia, How ever, analyses of symptom severity demonstrated that those with dysthymia e xhibited significantly less negative SW amplitudes with increasing depressi ve mood severity, whereas individuals with major depression demonstrated mo re negative SW amplitudes with increasing depressive mood severity, These r esults are discussed in the context of diagnostic specificity for cognitive biases associated with working memory of mood-disordered individuals.