A new study has found that in patients with hoarding disorder, parts of a decision-making brain circuit are under-activated when dealing with others' possessions. They also found that it is over-activated when deciding whether to keep or discard their own things. The study was funded by National Institute of Mental Health (NIMH). NIMH is part of the National Institutes of Health.
Brain scans revealed the abnormal activation in areas of the anterior cingulate cortex and insula known to process error monitoring, weighing the value of things, assessing risks, unpleasant feelings, and emotional decisions.
NIMH grantee David Tolin, Ph.D., of Hartford Hospital, Hartford, Conn., and colleagues, report on their functional magnetic resonance imaging (fMRI) study in the August 2012 issue of the journal Archives of General Psychiatry.
The new findings pinpoint brain circuit activity suspected of underlying the lack of self-insight, indecisiveness, sense that the wrong decision is being made, inflated estimates of the desirability of objects, and exaggerated perception of risk that are often experienced with the disorder.
In the study, brain activity of 43 hoarding disorder patients was compared to that of 31 obsessive compulsive disorder (OCD) patients and 33 healthy controls while they had to decide whether to keep or discard their own or others' junk mail and newspapers. Notably, such ownership did not appear to differentially affect brain activity in the OCD patients. Hoarding disorder patients, as expected, decided to keep many more items than the other groups.
"The results of this study reflect an accelerating trend toward finding disturbed regulation of brain systems responsible for various dimensions of behavior that may cut across mental disorders as traditionally defined," said Bruce Cuthbert, Ph.D., director of NIMH's Division of Adult Translational Research.
In this case, the implicated brain areas are hubs of a salience network that weighs the emotional significance of things and regulates emotional responses and states. Hoarding patients' severity of symptoms, self-ratings of indecisiveness, and feeling of things being "not just right" were correlated with the degree of aberrant activity in these hubs. The results add to evidence of impaired decision-making in hoarding disorder and may help to disentangle its brain workings from those of OCD and depression.