Brain Activity Different in Hoarders

Megan Brooks

August 08, 2012

August 8, 2012 — Individuals with hoarding disorder exhibit abnormal activity in brain regions involved in decision-making, a new imaging study shows.

According to the investigators, the study's findings suggest that hyperactivity in the anterior cingulate cortex (ACC)–insula network during decision-making is characteristic of hoarding disorder "and may contribute to subjective indecisiveness and decisions to save."

"We have found in our clinical work that people who hoard frequently seem to get 'stuck' in the decision-making process, which makes them less able or less willing to decide whether to keep or discard things," first author David F. Tolin, PhD, from Yale University School of Medicine in New Haven, Connecticut, told Medscape Medical News.

Dr. David Tolin

The study is published in the August issue of Archives of General Psychiatry.

Implications for DSM-5?

The current findings, said Dr. Tolin said, "suggest that hoarding should be considered separate from obsessive-compulsive disorder [OCD], and that it deserves recognition as a unique psychiatric disorder."

"It also shows us that people who hoard have a hard time processing information normally, and that when they have to make a decision, their brain goes into overdrive — specifically, those parts that are involved with identifying the relative importance or significance of things."

The study is "the first to investigate what happens in the brain when individuals with hoarding disorder make decisions about what to keep and what to discard," David Mataix-Cols, PhD, from the Institute of Psychiatry, King's College London, in the UK, told Medscape Medical News.

He said the results are "very timely given the current deliberations to include a new diagnostic category in the DSM-5 [Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition] and further delineate the differences between HD [hoarding disorder] and OCD. Until recently, hoarding was thought to be a symptom of OCD; now we know that most hoarders don't have OCD," he added.

Dr. Mataix-Cols was not involved in the research.

Dr. Tolin and colleagues enrolled 107 adults in their study; 43 had hoarding disorder (determined on the basis of clinical criteria proposed for DSM-5), 31 had OCD, and the remaining 33 were healthy individuals. While undergoing functional magnetic resonance imaging (fMRI), participants were shown paper items, such as junk mail and newspapers that did or did not belong to them.

Compared with the individuals who had OCD and the healthy individuals, patients with hoarding disorder exhibited abnormal activity in the ACC and insula, the researchers report.

CBT Effective?

Specifically, when deciding about items that did not belong to them, patients with hoarding disorder showed relatively lower activity in those brain regions. However, when deciding about items that did belong to them, these regions showed "excessive fMRI signals" compared with the other 2 groups, the investigators report.

These findings, Dr. Tolin and colleagues say, support "emerging models" of hoarding disorder that emphasize problems in decision-making processes that contribute to patients' difficulty discarding items.

The "apparent biphasic pattern" of ACC and insula activity (ie, hypofunction to items that did not belong to them and hyperfunction to items that did belong to them) in patients with hoarding disorder "merits further study," the authors conclude.

Dr. Mataix-Cols cautioned that "like most neuroimaging studies, the results only describe the brain regions implicated in deciding whether or not to discard items but do not explain the causes of such difficulties in individuals with hoarding disorder. Studies that tap into those causal mechanisms are sorely needed."

"The next thing we want to know," said Dr. Tolin, "is whether cognitive-behavioral therapy for hoarding can reverse these problems of brain function, and we are preparing a grant proposal for the National Institutes of Health to study that."

Dr. Tolin has received recent research support from Endo Pharmaceuticals, Merck, and Eli Lilly. A complete list of author disclosures is given in the original article. Dr. Mataix-Cols is an advisor to the DSM-5 Obsessive-Compulsive and Related Disorders work group that is proposing the inclusion of Hoarding Disorder in DSM-5. The study was funded in part by the National Institute of Mental Health.

Arch Gen Psychiatry. 2012;69:832-841. Abstract

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