Background: Mood disturbances have historically remained a core criterion in diagnosing major depressive episode. DSMs have illustrated this criterion with depressed, hopeless, discouraged, cheerless, and irritable mood, suggesting interchangeability. Extant research has examined individual forms of mood disturbance to depression severity. Less examined is the heterogeneity in mood disturbances and its implication to their asso-ciation to depression presentations and outcomes. Method: The current study used a nationally representative sample of U.S. adults with unipolar major depressive disorder to study the association between specific forms of mood disturbances to depression severity, chronicity, or symptoms, above and beyond other forms, as well as their relations to functional impairment, suicidal out-comes, and psychiatric comorbidity via generalized linear models. Results: Cheerless and hopeless mood were associated with depression severity. Hopeless and irritable mood were associated with depression chronicity. Different forms of mood disturbance showed differential relations to depressive symptoms. Cheerless, hopeless, and irritable mood were associated with depression-specific func-tional interference, incremental to depression severity. Cheerless, hopeless, and discouraged mood were asso-ciated with passive suicidal ideation. Hopeless mood was associated with active suicidal ideation. Hopeless and irritable mood were associated with both suicide plan and suicide attempt. Different forms of mood disturbance demonstrated differential associations to comorbid psychiatric conditions. Discussion: The relations between different forms of mood disturbances and various aspects of depression are nuanced. Theoretically, these relations highlight the potential utility in acknowledging the complexity and heterogeneity in mood disturbances. Clinically, our results suggest potential utility in routinely monitoring mood disturbances.