Hoarding versus collecting: where does pathology diverge from play?

A new diagnosis termed Hoarding Disorder has been proposed for inclusion in the upcoming DSM-5 to cover the majority of cases where severe hoarding occurs in the absence of, or independently from other mental disorders. Much effort has been directed to ensuring that the proposed criteria discriminate Hoarding Disorder from other mental disorders, particularly those historically associated with hoarding (e.g. OCD, OCPD). Considerably less attention, however, has been paid to addressing the suitability of the proposed criteria for effectively differentiating pathological hoarding from normative collecting behavior. This is crucial in order to avoid false positives or the overpathologization of this widespread human activity. Collecting behavior mirrors many of the core features of hoarding (e.g. the acquisition of and emotional attachment to a potentially large number of objects), is highly prevalent and is generally considered a normative form of object amassment; as such, it represents a valid population with which to explore the diagnostic boundaries of Hoarding Disorder. Examination of the collecting literature, within the context of the hoarding diagnostic criteria, indicates that, for the majority of collectors, a diagnosis of Hoarding Disorder is likely to be effectively ruled out. For a minority of 'extreme' collectors, a diagnosis may potentially be adequate. This review highlights the similarities and differences between hoarding and collecting and offers suggestions for further research in this group.