A new study of brain activity in patients with hoarding disorder has found they exhibit abnormal activity in regions of their brain when deciding whether to keep or discard things.

The study findings, which are reported in the August issue of Archives of General Psychiatry, also provide support for the argument that hoarding be regarded as being separate from other psychiatric disorders such as obsessive-compulsive disorder (OCD), with different treatments applied.

“We wanted to see whether the brain activity of people who hoard is different from that of people with OCD, and whether it is different from that of healthy people,” said David Tolin, founder and Director of the Anxiety Disorders Center at Chicago’s Institute of Living

Hoarding disorder is defined as the excessive collection of objects and an inability to discard them.

The Institute of Living study included 107 adults, and compared neural activity among 43 patients with hoarding disorder, 31 patients with OCD, and a group of 33 healthy individuals.

Compared with patients who had OCD and the healthy individuals, researchers found that patients with hoarding disorder exhibited abnormal activity in the anterior cingulate cortex and insula. 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 functional magnetic resonance imaging signals” compared with the other two groups, according to study results.

“These findings further suggest that hoarding should be considered separate from OCD, and that it deserves recognition as a unique psychiatric disorder,” Dr Tolin said.

“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.”

A separate classification category for hoarding disorder, which has previously been treated as a sub-type of obsessive compulsive disorder, will be included in the 2013 Diagnostic and Statistical Manual of Mental Disorders (DSM), published by the American Psychiatric Association.

“I think it’s fantastic because it actually forces mental health services to start looking at hoarding disorder as a separate problem,” said Michael Kyrios, Professor of Clinical Psychology and Director of the Brain & Psychological Sciences Research Centre at Swinburne University of Technology.

Professor Kyrios said the Institute of Living study is very credible because it looks at people with just hoarding disorder and no other significant OCD symptoms.

“It looks at phenomena that are specific problems for people with hoarding disorder such as discarding your own possessions as opposed to discarding somebody else’s possessions,” Professor Kyrios said.

As knowledge on hoarding disorder grows, and the separate DSM classification is delivered Professor Kyrios agreed it’s likely the number of people being diagnosed with hoarding disorder will increase.

“As soon as you describe something people start looking for it and soon as you start looking for it you’ll find that the incidence will go up,” Professor Kyrios said.

“However, if the problem exists in the community, it’s better that we have accurate prevalence rates so we can better plan relevant responses and policies. “

Dr Tolin said the Institute of Living now wants to explore whether cognitive-behavioural therapy for hoarding can reverse these problems of brain function.

In advance of the DSM classification for hoarding disorder, Professor Kyrios said state authorities in NSW, Victoria and Queensland are already developing policies on how to respond to hoarding problems in the community.

Professor Kyrios has also helped develop cognitive behaviour therapy treatments in Australia, which he said are seeing very promising results.

“The focus of the treatment for hoarding is not to throw away things, it’s to find areas of the house that aren’t being used for their intended purpose and to help find ways of clearing away those spaces so that people can use those spaces in a more positive and more constructive way.

“There are no medications specifically for hoarding, there are no medications that can teach you to sort or organise in a systematic manner.”