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August 20, 2012
Distinct Brain Activity in Hoarders
Certain brain regions under-activate in people with hoarding disorder when dealing with others' possessions but over-activate when deciding whether to keep or discard their own things. The new findings give insight into the biology of hoarding and may guide future treatment strategies.
People with hoarding disorder have trouble making decisions about when to throw things away. Possessions can pile up and result in debilitating clutter. Until recently, hoarding disorder has been considered a type of obsessive-compulsive disorder (OCD). Many experts, however, now consider it a unique diagnosis.
Previous studies of brain function in hoarders implicated regions associated with decision-making, attachment, reward processing, impulse control and emotional regulation. But the patient populations and research methods varied between the studies, making it difficult to draw clear conclusions.
In the new study, a research team led by Dr. David Tolin of Hartford Hospital and Yale University used functional magnetic resonance imaging (fMRI) to investigate the neural basis for hoarding disorder. They compared the brains of patients with hoarding disorder to patients with OCD and healthy controls as they decided whether to keep or discard possessions. The study was funded by NIH’s National Institute of Mental Health (NIMH).
The researchers analyzed brain images of 43 hoarders, 31 people with OCD and 33 healthy controls. Participants were given 6 seconds to make a decision about whether to keep or discard junk mail that either belonged to them or to someone else. Participants later watched as the items they chose to discard were placed in a paper shredder. They were then asked to rate their emotions and describe how they felt during the decision-making tasks. The results appeared in the August 2012 issue of the Archives of General Psychiatry.
The hoarders chose to keep more mail that belonged to them than those in the OCD or healthy control groups. Hoarders also took longer to make decisions and reported greater anxiety, indecisiveness and sadness than the other groups.
The imaging analysis revealed that hoarders differ from both healthy controls and patients with OCD in 2 specific brain regions: the anterior cingulate cortex and insula. Scientists believe that these areas are part of a brain network involved in processing emotion. Both regions were more active in hoarders when they were making decisions about mail that belonged to them, but less active when making decisions about mail that didn't belong to them.
These results suggest that hoarders' decisions about possessions are hampered by abnormal activity in brain regions used to identify the emotional significance of things. “They lose the ability to make relative judgments, so the decision becomes absolutely overwhelming and aversive to them,” Tolin says.
The scientists believe that these brain abnormalities are specific to hoarding and separate the disorder from OCD. In addition to further exploring the unique traits of hoarders, the researchers are now using this information to help assess potential treatments.
Reference: Arch Gen Psychiatry. 2012 Aug 1;69(8):832-41. PMID: 22868937