Abstract
Hoarding disorder, a complex syndrome marked by extreme difficulty discarding possessions and debilitating clutter, is increasingly recognized as a severe and impairing public health burden. Within the cognitive-behavioral model of hoarding, specific information processing difficulties have been implicated as contributing factors, including (1) attention, (2) memory, and (3) executive functioning difficulties associated with decision making, categorization abilities, and impulsivity. The authors first outline general issues and considerations relevant to the study of neuropsychological factors, followed by a more specific examination of the extant literature on hoarding. For each of the primary neurocognitive deficits hypothesized for hoarding disorder, this review outlines and evaluates past research. In summary, there is a strong indication that the attentional system is compromised in hoarding disorder, particularly with respect to inattention. Furthermore, there is suggestive evidence for recall deficits of both verbal and visual information, along with less efficient organization of visual information for encoding purposes. Data on categorization abilities also provide evidence that individuals with hoarding rely on a greater number of underinclusive categories. Less convincing evidence has been obtained for decision making, impulsivity, and planning. For each of the larger information processing domains, the authors discuss limitations and highlight unexplored avenues for future study. In general, the study of neurocognitive deficits in hoarding represents a highly promising area for future research, though one that is still in its nascent stage.