Abstract
Rumination and worry are two types of repetitive negative thinking (RNT) that have been identified as risk factors for depression and anxiety. Over the past decade, research has slowly shifted away from the notion that rumination and worry are separate, disorder-specific processes and towards focus on a general process of RNT to investigate transdiagnostic risk. However, few studies have treated rumination and worry under a multidimensional conceptualization in which they share a common cognitive process (i.e., RNT) while retaining distinct features (e.g., temporal orientation of thought). Additionally, little research has directly examined mechanisms that may influence the common process of RNT. This dissertation included four studies that aimed to provide further evidence for the transdiagnostic nature of RNT, elucidate individual characteristics and environmental factors that increase risk for engaging in repetitive, negative, and uncontrollable thinking, and determine adverse outcomes of engaging in such processes.
Study 1 used a longitudinal research design to examine the validity, reliability, and usefulness of a multidimensional bifactor model of RNT. Results showed that the bifactor model was well-fitting and reliable, and the common RNT component was a predictor of later (but not change in) anhedonic depression and anxious arousal symptoms. Study 2 used an eight-week longitudinal study during the COVID-19 pandemic to examine a diathesis-stress model of RNT, which hypothesized that an intolerance to uncertainty would strengthen stress as a mechanism for engaging in RNT during a particularly uncertain and stressful period. Stress and intolerance of uncertainty each predicted the common RNT component, but the diathesis-stress model was not supported. Study 3 examined how individual differences in task-based and survey-based cognitive control abilities impact the likelihood of experiencing stress and subsequent RNT in a one-semester longitudinal study. This risk pathway was supported for executive functioning task performance and self-reported attentional control, but not working memory capacity task performance. Study 4 utilized ecological momentary assessment to further assess how different types of cognitive control abilities impact real-life experiences of stress, RNT, and affect. Between-persons, results showed that difficulties with shifting away from negative information (i.e., “hot shifting”) was associated with higher levels of RNT, while difficulties with inhibiting irrelevant neutral information (i.e., “cold inhibition”) was associated with more negative appraisals of stressor severity and controllability. Within-persons, results showed that stress occurrence and negative stress appraisals predicted an increase in RNT engagement, and higher levels of RNT engagement predicted an increase in negative affect and decrease in positive affect. Critically, conclusions from this dissertation provide important insights for developing clinical interventions aimed at reducing transdiagnostic RNT and risk for internalizing psychopathology.