Mood-as-input hypothesis and perseverative psychopathologies.

Mood-as-input hypothesis is a theory of task perseveration that has been applied to the understanding of perseveration across psychopathologies such as pathological worrying, compulsive checking, depressive rumination, and chronic pain. We review 10 years of published evidence from laboratory-based analogue studies and describe their relevance for perseveration in clinical populations. In particular, mood-as-input hypothesis predicts that perseveration at a task will be influenced by interactions between the individual's stop rules for the task and their concurrent mood, and that the valency of an individual's concurrent mood is used as information about whether the stop rule-defined goals for the task have been met. The majority of the published research is consistent with this hypothesis, and we provide evidence that clinical populations possess characteristics that would facilitate perseveration through mood-as-input processes. We argue that mood-as-input research on clinical populations is long overdue because (1) it has potential as a transdiagnostic mechanism helping to explain the development of perseveration and its comorbidity across a range of different psychopathologies, (2) it is potentially applicable to any psychopathology where perseveration is a defining feature of the symptoms, and (3) it has treatment implications for dealing with clinical perseveration.