The Unique and Interacting Contributions of Intolerance of Uncertainty and Rumination to Individual Differences in, and Diagnoses of, Depression

Intolerance of uncertainty (IU) and the tendency to repetitively think in a negative way about oneself are established contributors to depression; however, no study has yet examined the unique and interacting effects of these variables to depression symptoms and diagnoses amongst people with major depressive disorder (MDD). People with MDD (n = 48) and diagnoses-free, community controls (n = 66) completed self-report measures of depression, anxiety and IU, as well as constructive (focusing on how events occurred) and unconstructive (focusing on how events felt) rumination. In a linear regression, greater IU and diminished constructive rumination, and the interaction between IU and unconstructive rumination, each explained variance in depression symptoms, even when anxiety symptoms were accounted for. In a logistic regression, these variables did not contribute towards MDD diagnoses once anxiety symptoms were accounted for. Rumination about one’s mood is associated with enhanced distress during uncertainty, with detrimental effects for one’s depression symptoms.