Compulsive hoarding is a problem that is characterized by excessive collecting and the failure to discard excessive amounts of collected items, in addition to the cluttering of living space and significant distress or impairment caused by the hoarding. Between 15-40% of OCD sufferers report saving and hoarding compulsions but there is some uncertainty about the relationship between hoarding and OCD. A study of 52 people by researchers at the Institute of Psychiatry in London compared 25 people with severe compulsive hoarding and OCD and 27 people with compulsive hoarding without OCD. Overall the nature of hoarding behaviour was similar between the two groups with the majority of the participants in both groups reporting hoarding common items as a result of their emotional and/or intrinsic value. However, about a quarter of the hoarders with OCD hoarded bizarre items and had other obsessions and compulsions related to their hoarding such as a fear of catastrophic consequences, the need to perform checking rituals and the need to perform mental compulsions before discarding any items and these people had a much more severe and disabling form of the disorder. The researchers concluded that in most individuals compulsive hoarding appeared to be a syndrome separate from OCD but that in otheer individuals it is a symptom of OCD and has unique clinical features.
Pertusa, Alberto ... [et al] - Compulsive hoarding: OCD symptom, distinct clinical syndrome or both? American Journal of Psychiatry October 2008, 165(10), 1289-1298