Compulsive Hoarding (Hoarding Disorder) is a pattern of behavior that is characterized by the excessive acquisition of and inability or unwillingness to discard large quantities of objects that cover the living areas of the home and cause significant distress or impairment. Compulsive hoarding behavior has been associated with health risks, impaired functioning, economic burden, and adverse effects on friends and family members. When clinically significant enough to impair functioning, hoarding can prevent typical uses of space so as to limit activities such as cooking, cleaning, moving through the house, and sleeping. It can also be dangerous if it puts the individual or others at risk from fire, falling, poor sanitation, and other health concerns.
Brain imaging studies using positron emission tomography (PET) scans that detect the effectiveness of long-term treatment have shown that the cerebral glucose metabolism patterns seen in OCD hoarders were distinct from the patterns in non-hoarding OCD. The most notable difference in these patterns was the decreased activity of the dorsal anterior cingulate gyrus, a part of the brain that is responsible for focus, attention and decision making. A 2004 University of Iowa study found that damage to the frontal lobes of the brain can lead to poor judgment and emotional disturbances, while damage to the right medial prefrontal cortex of the brain tends to cause compulsive hoarding.
Other neuropsychological factors that have been found to be associated with individuals exhibiting hoarding behaviors include slower and more variable reaction times, increased impulsivity, and decreased spatial attention.