Clarifying the unique associations among intolerance of uncertainty, anxiety, and depression*

Increasing evidence suggests that intolerance of uncertainty (IU) may be a transdiagnostic factor across the anxiety disorders, and to a lesser extent, unipolar depression. Whereas anxiety inherently involves uncertainty regarding threat, depression has traditionally been associated with certainty (e.g. the hopelessness theory of depression). Some theorists posit that the observed relationship between depression and IU may be due to the relationship between depression and anxiety and the relationship between anxiety and IU. The present study sought to elucidate the unique relationships among trait anxiety, depression, and IU in undergraduate (N = 554) and clinical (generalized anxiety disorder; N = 43) samples. Findings suggest that IU may play a larger role in anxiety than depression, although some evidence indicates that inhibitory IU and depression may have a modest but independent relationship.