Tracking Rumination as a Stable Habit (TRASH); Scale Modification and Convergent Validity in a Clinical Sample of Youth With a History of Depression.

Rumination is a cognitive habit involving repetitive negative thinking (RNT). It is a risk factor for depression and develops during late childhood. Targeted interventions to reduce rumination are critical for reducing risk for and impact of depression. Therefore, quick and sensitive scales are needed to capture concrete, quantifiable changes in rumination habit. We developed and evaluated the Tracking Rumination As a Stable Habit (TRASH) measure, to align with Rumination-Focused Cognitive Behavioral Therapy (RF-CBT). The scale was derived, modified and expanded on from the Habit Index of Negative Thinking (HINT). TRASH assesses automaticity and consistency of the habit, quantifiable elements of the daily habit. As part of a larger trial of RF-CBT, 120 adolescents (age mean [sd]: 15.73 [1.11], 67.5% female) completed all scales. Internal reliability of the scale was high (overall α = 0.86, Automaticity α = 0.85, Consistency α = 0.72). The scale demonstrated moderate to strong convergent validity with existing measures of RNT (rs [118] = 0.43 to 0.46). Associations with anxiety, worry and depression measures were modest and variable (rs [118] = 0.13 to 0.63). Divergent and/or nonrelated validity with scales, included null and negative relationships (rs [118] = -0.23 to 0.39). Exploratory analyses identified a general RNT factor (including worry, rumination), a TRASH subfactor, and distinct affective RNT subfactors (e.g., angry, apathetic). Treatment by time interactions suggest similar changes over time in RNT scales, as well as the RNT main factor and the TRASH subfactor. Additional research is needed for the TRASH scale, if it may be sensitive to concrete changes in rumination. ClinicalTrials.gov Identifier: NCT03859297.