The Automaticity of Depressive Rumination: A Test of the Habitual Nature of Ruminative Thinking in Clinical and Non-clinical Samples. Insights From an Ecological Momentary Assessment Perspective

Abstract

Background: Major depression is the most common psychiatric disorder, associated with the highest disease burden worldwide when it comes to years lost to disability. Efforts to identify indicators of depression risk have strongly implicated depressive rumination, a negative thinking style characterized by repetitive and passive thoughts about the causes, meanings, and consequences of one's feelings and distress. An increasingly popular theoretical perspective posits that over time depressive rumination becomes a mental habit that is initiated automatically without conscious awareness or intent in response to downward shifts in mood, making it persistent and difficult to control. However, the rumination as-a-habit account has rarely been directly tested and it is still unknown whether depression vulnerability is characterized by elevated levels of mood-reactive habitual rumination at the level of short-term dynamics.

Aims: The aim of the current research project was to address gaps in the current knowledge on depression vulnerability by utilizing a combination of experimental and novel mobile in-the-moment assessment strategies to better understand the dynamic interplay between mood and ruminative thinking and its habitual characteristics. Three studies were designed to test specific hypotheses involving: a) effects that fluctuations in mood have on subsequent ruminative thinking, b) the degree to which habitual characteristics of negative thinking predict such mood-reactive rumination, and c) whether mood-reactive rumination varies according to the depression-risk spectrum in line with theoretical accounts of depression vulnerability. Methods: In study 1, a total of 115 university students completed self-report measures and participated in an experimental rumination-induction task and outcome-devaluation task measuring habit vs. goal-directed behaviour control. In study 2, a total of 97 participants recorded affect and rumination ten times daily over six days using Ecological Momentary Assessment, after completing measures of trait ruminative brooding and habitual characteristics of negative thinking (e.g., automaticity, lack of conscious awareness, intent, and control). In study 3, formerly depressed individuals with a recurrent history of depression (n = 94) and non-clinical controls (n = 55) recorded in-the-moment affect and rumination ten times daily over six days, after completing baseline measures of trait ruminative brooding, habitual characteristics of negative thinking, and early-life stress.

Results: In study 1, greater habitual characteristics of negative thinking were associated with ruminative brooding but not ruminative reflection, and predicted more persistent dysphoric mood following rumination-induction. Rumination was not, however, consistently associated with an imbalance in habit vs. goal-directed behaviour control. In study 2, momentary fluctuations in negative (increased) and positive (decreased) affect was prospectively associated with greater rumination at the next sampling occasion. The degree to which affect triggered a subsequent ruminative response was moderated by habitual characteristics of negative thinking in a theoretically consistent way. Stronger temporal pairing of negative affect and rumination was also associated with greater emotional inertia but less carry-over of rumination from one moment to the next. In study 3, momentary fluctuations in negative affect were prospectively associated with greater rumination at the next sampling occasion in formerly depressed participants whereas this pattern of mood-reactive rumination was not observed in healthy never-depressed participants. In formerly depressed participants, habitual characteristics of negative thinking were associated with greater mood-reactivity of rumination, particularly among those with a history of early-life stress. Mood-reactive rumination was not, however, associated with depression course nor trait ruminative brooding.

Conclusions: The findings of the studies demonstrate that fluctuations in affect can trigger ruminative thinking as a function of habit consistent with recent theoretical frameworks of depression vulnerability. Mood-reactive rumination may be a potential vulnerability marker for depression, with rumination being habitually triggered in response to momentary fluctuations in negative affect with a high degree of automaticity, and with a deleterious effect on mood. The current thesis suggests ways depression vulnerability may emerge as a dynamic relationship between negative affect and rumination across time, not captured by traditional trait measures of rumination frequency. Ecological momentary assessment may be a valuable measurement paradigm to test predictions derived from habit-accounts of depressive rumination, that have rarely been investigated until now, and might provide new insights into research on depression risk.