Ruminative Variability Predicts Increases in Depression and Social Anxiety.

Background: Rumination is a well-established contributor to the severity of depression and anxiety. It is unknown, however, whether individual differences in the temporal dynamics of rumination over time predict longitudinal increases in depression or anxiety. Methods: The current study examined whether the dynamic indices of ruminative inertia and variability assessed over 14 days via ecological momentary assessment predicted change in symptoms of depression, general anxiety, and social anxiety at a 90-day follow-up ( Results: Controlling for ruminative variability, baseline levels of the dependent variable, sex, and mean levels of momentary rumination, ruminative inertia did not predict change in symptoms of depression, general anxiety, or social anxiety at the 90-day follow-up. In contrast, greater ruminative variability predicted increases in symptoms of both depression and social anxiety but not general anxiety at follow-up. Individuals endorsing higher baseline levels of depressive symptoms demonstrated greater amounts of inertia and variability in their momentary rumination. Greater ruminative variability but not inertia was also associated with higher baseline levels of general anxiety and social anxiety. Conclusions: These results suggest that ruminative variability may be a risk factor for increases in symptoms of depression and social anxiety over time and a potentially useful target for clinical intervention.