Compulsive hoarders are more likely to suffer from executive dysfunction, a cognitive deficit that inhibits flexible thinking and categorisation skills, a study has found.
The findings, published in the journal Behavioural and Cognitive Psychotherapy, suggest that forcing hoarders to clear their homes of junk does little to solve the problem because it doesn't address the dysfunction causing the hoarding in the first place.
The authors of the study analysed a group of 24 compulsive hoarders aged between 39 and 65 years, comprised of 18 women and six men. An age-matched control group was also studied.
The subjects participated in three tests. In the first, known as the Digit Span, the subjects were asked to repeat back a series of numbers spoken to them by the researcher in the original order and in reverse order.
In the second test, called the Spatial Span test, the researchers tapped a set of blocks in a sequence and asked the subjects to repeat the sequence in both the original and the reverse order.
The third test was called the Wisconsin Card Sorting Test, a card-matching game where subjects are asked to match cards but are not told the rules of the game. In this game, the criteria upon which cards are matched, such as colour or shape, are changed several times throughout the game.
All three tests are aimed at determining the participant's mental flexibility, adaptation and focus.
The researchers found that compulsive hoarders find it harder to formulate strategies and concepts, and struggle with memory, attention span and categorisation.
"They scored lower than an age-matched community sample of adults on things like sustained attention and organisation skills," said co-author of the study, Associate Professor Clare Rees from Curtin University's School of Psychology.
"They appear to have impairments in the ability to respond flexibly to changing stimuli and showed more impulsivity in response to the tasks."
Study participants also had difficulty noting similarities between the objects and in identifying which categories the items belonged to, the study found.
That may help explain why compulsive hoarders tend to see each item as special and unique, leading to difficulties in discarding items.
"For example, when faced with the decision as to what to do with a possession (such as where to store it in the home, whether to keep it or not keep it, whether to sell it or donate it to charity or discard it) a person needs to be able to sustain attention, establish some working categories or rules about what to do and follow through with the application of those rules," said Associate Professor Rees.
"Our study found that each of these abilities—the ability to sustain attention, adhering to an organisational strategy, and being able to be flexible in the application of the strategy—were all impaired in our sample of hoarders."
In addition, a tendency toward impulsivity might help explain why an object may be thrown into a room rather than being sold or properly discarded, she said.
"In practice, these results suggest that we should be designing interventions which focus more on training the cognitive abilities of people who hoard, so that they can build up their ability to sustain attention and adhere to categorising objects according to functional 'rules'," Associate Professor Rees said.
"Interventions that merely attempt to reduce the amount of possessions in a hoarders home are likely to fail because they are not helping the person develop the mental skills necessary to manage their possessions effectively into the future."
Dr Jessica Grisham, a hoarding researcher at the University of NSW, said the study's findings had "great potential for implementation for those with compulsive hoarding."
Dr Grisham said it was hard to research large sample sizes of hoarders, because many also suffer from anxiety or obsessive-compulsive disorder, making it harder to isolate certain behaviours for study.