Mood-as-input and depressive rumination.

This article describes a test of mood-as-input theory predictions as applied to a rumination task in a nonclinical population. An experimenter-controlled interview was used to allow participants to reflect on a personal period of depression while in an experimentally-induced mood state (either negative or positive) or while deploying a specific stop rule for the task (either an "as many as can" or "feel like continuing" stop rule). As predicted by mood-as-input theory, persistence at the rumination task was greatest in the group experiencing negative mood while deploying an "as many as can" stop rule, and this suggests a mechanism that may contribute to perseverative depressive rumination. It is argued that the variables that contributed to perseveration in this study are already known to be characteristic of ruminative thinkers (e.g. negative mood and positive metacognitive beliefs about rumination that will command the deployment of "as many as can" stop rules for rumination). It is also argued that mood-as-input processes may provide a common mechanism for perseverative rumination and perseverative worry, and this common mechanism may account for many of the similarities between these two functionally-distinct activities.