Distress tolerance has been implicated in the emergence of internalizing symptomatology, notably depressive symptoms. However, few studies have tested potential mechanisms underlying the relationship between distress tolerance and depressive symptoms, and further, this has not been tested among substance users, who commonly experience both low distress tolerance and elevated depressive symptoms. The current study focused on the construct of rumination, which has been suggested to be a coping response to stress associated with substance use and depression. Two forms of rumination, brooding and reflection, were tested as potential mediators of the relationship between distress tolerance and self-reported depressive symptoms among 128 individuals entering substance abuse treatment. Brooding (i.e., to overly focus on symptoms of distress) mediated the relationship between distress tolerance and depressive symptoms. However, reflection (i.e., to attempt to gain insight into problems) was unrelated to distress tolerance. Findings suggest the important role of brooding as a mechanism underlying the relationship between distress tolerance and depressive symptomatology
