Review of cognitive performance in hoarding disorder.

Hoarding disorder is characterized by extreme difficulty letting go of objects other people would routinely discard or give away, such that the home becomes dysfunctionally cluttered with possessions. Specific cognitive processes, such as decision-making, categorization, and attention, have been hypothesized to contribute to the overvaluing of objects. This review synthesizes the evidence related to those propositions and other executive functioning processes that have received research attention. In this paper, we are primarily interested in cognitive processes that can be, but are not always, studied using performance tasks. Compared to both healthy controls and clinical controls, participants with clinical levels of compulsive hoarding show replicable performance deficits in several areas: planning/problem-solving decisions, visuospatial learning and memory, sustained attention/working memory, and organization. Categorization/concept formation, visuospatial processing, and inhibitory control require further investigation and more detailed testing methods to address inconsistencies in reported findings. Many studies fail to account for potential confounds presented by comorbid depression and between-group differences in age, a problem that should be rectified in future research on this topic. The article concludes with recommendations for a research agenda to better understand contributors to abnormal valuing of objects in hoarding disorder.