David Mataix-Cols,1Alberto Pertusa,1and John Snowdon2
1King’s College London
2University of Sydney
Hoarding can be a symptom of multiple neurological and psychiatric disorders, including obsessive-
compulsive disorder (OCD). Recent evidence suggests that, in many cases, hoarding can also be a
standalone problem that presents independently from other conditions; this has led to the proposal of a
new diagnostic entity named hoarding disorder. This article reviews the neuropsychological and
neuroimaging research on pathological hoarding. Most research in humans has been conducted in the
context of individuals with brain damage, dementia, or OCD. Studies of well-characterized samples of
individuals with hoarding disorder are extremely rare. Although not possible to establish firm
conclusions at this stage, we conclude with a series of observations and recommendations for clinical
practice. & 2011 Wiley Periodicals, Inc. J Clin Psychol: In Session 67:467–476, 2011.
Keywords: hoarding disorder; neuropsychology; neuroimaging; brain lesion; dementia; OCD; clinical practice
Collecting and saving possessions is a widespread human behavior, which is likely to be
evolutionarily conserved (Leckman, Rauch, & Mataix-Cols, 2007). Like most human
behaviors, collecting and saving possessions can range from totally normal and adaptive to
excessive or pathological. Indeed, in severe hoarding cases, clutter prevents the normal use of
space to accomplish basic activities, such as cooking, cleaning, moving through the house, and
even sleeping. Interference with these functions can make hoarding a dangerous problem,
putting people at risk for fire, falling (especially elderly people), poor sanitation, and health
risks (Damecour & Charron, 1998; Frost, Steketee, & Williams, 2000; Steketee & Frost, 2003;
Thomas, 1997). Pathological hoarding can represent a profound public health burden in terms
of occupational impairment, poor physical health, and social service utilization. It also has a
substantial impact on the family members.
It is clear that excessive accumulation of items or pathological hoarding can be secondary to
a wide range of neurological and psychiatric conditions, such as brain damage, dementia,
obsessive-compulsive disorder (OCD), schizophrenia, and autism (see Pertusa, Frost, Fullana
et al., 2010 for a comprehensive review). The link with OCD has been regarded as particularly
strong, primarily because of historical reasons (see Mataix-Cols et al., 2010).
Only recently has it become apparent that hoarding problems can occur independently from
other conditions, including OCD. This has prompted the proposal of a new diagnostic
category for the Diagnostic and Statistical Manual of Mental Disorders 5th Edition (DSM-V)
named hoarding disorder (Mataix-Cols et al., 2010). Of crucial importance is that for an
individual to fulfill criteria for hoarding disorder, other neurological and psychiatric disorders
need to be carefully ruled out (diagnostic criteria E and F). Research into the psychological
and biological processes underlying hoarding problems has grown exponentially over the last
decade, following the publication of the initial operational definition of compulsive hoarding
(Frost & Hartl, 1996). This article reviews the neuropsychological and neuroimaging research
on pathological hoarding with the intent of informing clinical practice. We begin by
We thank Ms. Lorena Fernandez de la Cruz for her assistance in the preparation of this manuscript.
Correspondence concerning this article should be addressed to: David Mataix-Cols, Departments of
Psychosis Studies and Psychology, King’s College London, Institute of Psychiatry, PO 69, De Crespigny
Park Road, London SE5 8AF, United Kingdom; e-mail: firstname.lastname@example.org
JOURNAL OF CLINICAL PSYCHOLOGY: IN SESSION, Vol. 67(5), 467--476 (2011)
Published online in Wiley Online Library (wileyonlinelibrary.com/journal/jclp).
& 2011 Wiley Periodicals, Inc.
summarizing important terminological aspects. We then touch upon the animal, human brain
damage and dementia literature, which may provide useful clues about the neural substrates of
hoarding behavior. At this stage, it will be pertinent to discuss the phenomenological
similarities and differences between these organic forms of pathological collecting behavior
and hoarding disorder. Next, we will summarize the available neuroimaging and neuro-
psychological studies available. Finally, we advance a series of tentative conclusions and
recommendations that may inform clinical practice.
We use pathological hoarding or abnormal hoarding behavior as umbrella terms for any form of
excessive collecting or hoarding, irrespective of its nosology and etiology. We sometimes
employ the term organic hoarding when referring to the collection and accumulation of objects
by people known to have brain pathology or lesions (e.g., dementia or brain damage). In these
cases, the etiology of the problematic behavior is largely known and often documented using
brain scans. By contrast, we sometimes use the term nonorganic when discussing hoarding in
individuals with no known brain pathology or damage. This, of course, does not mean that
hoarding disorder does not have a biological substrate but much less is known about it.
Despite the widespread use of the term compulsive hoarding, we will employ it only when
referring to hoarding as a symptom of OCD (Pertusa, Frost, & Mataix-Cols, 2010). When
hoarding is independent from OCD and any other neurological and psychiatric conditions, we
will refer to it simply as hoarding disorder, as this is the suggested term in DSM-V.
Animal and Human Brain Damage Studies
The neural substrates of hoarding behavior have been well-studied in animals that naturally
display hoarding behaviors as part of their behavioral repertoire (e.g., rodents, birds), as well
as primates. These studies clearly implicate subcortical limbic structures (nucleus accumbens,
ventral tegmental area, amygdala, hippocampus, thalamus, hypothalamus) and the ventro-
medial prefrontal cortex in the mediation of hoarding behavior. For example, electrical
stimulation of lateral hypothalamus (a region that also promotes feeding) increases hoarding
behavior in rats (Herberg & Blundell, 1967).
Research with animals also suggests that the dopaminergic system plays a crucial role in
hoarding behavior. For example, neonatal depletion of dopaminergic meso-cortical
projections decreases hoarding in rats (Kalsbeek, De Bruin, Feenstra, Matthijssen, & Uylings,
1988) and hoarding behavior can be restored to control levels in dopamine-lesion rats by prior
treatment with L-dopa (Kelley & Stinus, 1985). Whether the known involvement of the
dopaminergic system in hoarding among animals can explain the relatively poor response of
hoarding individuals to serotonergic drugs (see Pertusa, Frost, Fullana et al., 2010 for a recent
review) is an attractive hypothesis that remains to be investigated.
Brain damage studies in humans (broadly understood as being of vascular, surgical, or
infectious origin) may provide useful clues as to what brain regions are important in mediating
or regulating abnormal hoarding behavior. Several case studies and case series of patients who
started hoarding after suffering brain damage suggest that the anterior ventromedial
prefrontal and cingulate cortices are implicated in abnormal hoarding behavior (e.g.,
Anderson, Damasio, & Damasio, 2005; Cohen, Angladette, Benoit, & Pierrot-Deseilligny,
1999; Hahm, Kang, Cheong, & Na, 2001; Volle, Beato, Levy, & Dubois, 2002).
In a comprehensive case series (Anderson et al., 2005), nine cases of pathological
collectionism/hoarding after brain damage were identified and their neuropsychological
profiles were compared with those of 54 brain damaged patients who did not display
pathological collecting/hoarding. All displayed persistent hoarding behavior that was not
present before the onset of the brain damage and led to obvious negative consequences for the
patients and their families. All nine collectors acquired items excessively and indiscriminately,
and eight of them also had diminished discarding behavior. Abnormal food collection was
evident in five of the cases. People who hoarded were described by their relatives as having
Journal of Clinical Psychology: In Session, May 2011
acquired deficits in planning, organizing, and controlling their impulses but not having
significant ‘‘obsessive tendencies.’’ In terms of neurocognitive performance, there were no
obvious differences between hoarding and nonhoarding cases with regard to verbal and
nonverbal intelligence, memory, or executive functions (including the Wisconsin Card Sorting
Test). Although the differences were not significant at the group level, perhaps because of
limited statistical power, four hoarders had significant memory impairments and six had
impairments on the Tower of Hanoi, a planning task. Analysis of the functional magnetic
resonance imaging (MRI) scans indicated that the maximal region of difference between the
two groups was the ventromedial prefrontal cortex, extending posteriorly to the anterior
cingulate cortex. Linking the animal and lesion literature, Anderson et al. (p. 201) concluded
that ‘‘the evidence suggests that damage to the mesial frontal region disrupts a mechanism
which normally modulates subcortically driven predispositions to acquire and collect, and
adjusts these predispositions to environmental context.’’
Additional evidence for the involvement of ventromedial prefrontal regions in pathological
hoarding comes from a handful of published cases of patients with the frontal variant of
frontotemporal dementia that included neuroimaging evidence (Mendez & Shapira, 2008;
Nakaaki et al., 2007). The features of the hoarding behavior appear to be similar to those
described in brain lesion studies. It is often accompanied by other neuropsychiatric symptoms
such as disinhibition, gambling, disorganization, rituals/stereotypies, tics, and self-injurious
behaviors (Mendez & Shapira). Neuropsychologically, these patients often show preserved
abilities on traditional frontal lobe tasks because these tasks tend to be more sensitive to
dorsolateral rather than ventromedial frontal lobe dysfunction (Nakaaki et al.). The following
case (adapted from Nakaaki et al.) illustrates the point nicely.
A 54-year-old with no previous history of neurologic or psychiatric disorder began to collect items
from the trash a few years earlier, when he was 48. Once a week, he would roam his neighborhood
and collect broken TV sets, clocks, bags, CDs, old newspapers, and magazines. He kept these
items in his house, despite being urged by his family to discard them. Gradually, his food
preferences also began to change; he began to eat large amounts of sweets every day. At age 51,
he started to exhibit more serious behavioral changes, including gambling, leading to significant
debts. He also began to exhibit abnormal sexual behavior, such as masturbating outdoors on a
He was arrested by the police and brought to the hospital for a neuropsychiatric assessment. He
displayed no insight into his own condition. A full neuropsychological assessment revealed intact
intellectual functioning, normal Mini-Mental State Examination score (score529), as well as
preserved memory, visuospatial skills, attention, and executive function (including performance on
the Wisconsin Card Sorting Test, letter fluency, Stroop and Trail Making Test).
However, he displayed marked difficulties on the Iowa Gambling Task (IGT), consistently
picking cards from the risky decks and failing to learn the more advantageous strategy.
A SPECT scan revealed significant hypometabolism in the left inferior frontal cortex (Brodmann
area [BA] 47), bilateral ventromedial prefrontal cortex (BA 9, 11), left cingulate gyrus (BA
32), and left insula. A diagnosis of frontotemporal dementia was eventually made.
Pathological hoarding behavior has also been described in Alzheimer’s dementia. For
example, 30 of 133 (23%) people with dementia admitted to a geropsychiatric ward in Taiwan
displayed hoarding behaviors (Hwang, Tsai, Yang, Liu, & Lirng, 1998). Of these, 24 had
Alzheimer’s dementia, four multi-infarct dementia, and two dementia not otherwise specified.
Neuropsychological Correlates of Hoarding
These findings could indicate that medial temporal brain regions may be also implicated in this
form of collectionism. Again, this would be consistent with the animal literature described above.
The above-mentioned discussion has not established whether the psychological and neural
mechanisms involved in organic hoarding are different than those implicated in hoarding
disorder. We now consider phenomenological differences between organic hoarding and
hoarding disorder per se.
Differences Between Organic Hoarding and Hoarding Disorder
Although direct comparisons have not been conducted, examination of the published cases
suggests apparent phenomenological differences between these two broad types of hoarding.
These differences are summarized in Table 1.
In organic cases, the onset of the problematic behavior appears shortly after the brain
damage occurs or the onset of the dementing process. In a way, its causes are known.
By contrast, the onset of hoarding disorder is insidious, has its origins in childhood/
adolescence, and usually has a long natural history before it becomes problematic (see Mataix-
Cols et al., 2010; Pertusa, Frost, Fullana et al., 2010 for reviews).
Although the items being collected/hoarded appear to be similar, only the organic hoarders
appeared to accumulate food, often decaying (Anderson et al., 2005; Hwang et al., 1998).
Interestingly, some of the people with OCD-related hoarding (that is, hoarding as a
compulsion in an individual with OCD) have also been found to accumulate rotten food and
body products (e.g., feces), but this has not been described in cases of hoarding disorder
(Pertusa et al., 2008).
A majority of older people living in very unclean dwellings (severe domestic squalor) have
been reported as accumulating large quantities of valueless material, commonly garbage.
Half of those who hoard to a major degree were found to have dementia or schizophrenia
(Snowdon & Halliday, 2011). Although some individuals with hoarding disorder can also live
in squalid environments, this appears to be much less frequent than in cases of organic
The nature of the acquisition may differ in that in some (but not all; see Volle et al., 2002)
organic cases, it may be more indiscriminate; these patients appear to have little interest in the
accumulated items and never use them (Anderson et al., 2005). In other brain-damaged cases,
however, the collecting behavior can be truly goal-directed rather than indiscriminate
(Anderson et al.; Volle et al.). In hoarding disorder, patients who acquire generally do so
purposefully and have a strong interest in the collected items, driven by the emotional or
intrinsic value they attribute to these items.
Some of the organic hoarders seem to be able to discard their possessions easily or do not
seem to care if others discard them, whereas others appear to be very reluctant to discard any
of their accumulated items (Anderson et al., 2005). By definition, all people with hoarding
disorder have difficulties and experience great distress when discarding their possessions.
In individuals with brain damage or dementia, the collecting behavior may be accompanied
by severe personality changes as well as behaviors commonly attributable to brain
dysfunction, such as gambling, inappropriate sexual behavior, excessive shopping leading to
financial difficulties, theft, stereotypies, tics, and self-injurious behaviors (Anderson et al.,
2005; Mendez & Shapira, 2008; Nakaaki et al., 2007). Although some of these behaviors,
particularly excessive buying, have anecdotally been described in hoarding disorder (Mataix-
Cols et al., 2010; Steketee & Frost, 2003), they appear to be less prevalent or impairing.
To summarize, animal and brain damage/dementia studies in humans may provide useful
clues as to what brain regions are important in mediating or regulating abnormal collecting
behavior and the typical neuropsychological profile associated with these patients. The
evidence so far suggests that ventromedial prefrontal and medial temporal brain regions are
implicated in these organic forms of hoarding. However, much caution is needed before
extrapolating these findings to nonorganic hoarding cases, as there appear to be some clear
Journal of Clinical Psychology: In Session, May 2011
Neuroimaging Studies of Nonorganic Hoarding
A limited number of neuroimaging studies have examined the neural correlates of hoarding,
primarily in the context of OCD. These can be broadly divided into resting state and symptom
Phenomenological Differences Between Hoarding Behavior Due to Macroscopic Brain Damage
(Organic Hoarding) and Hoarding in Hoarding Disorder
Organic hoardingHoarding disorder
Onset Generally sudden in cases of brain
damage. Can be insidious if
secondary to a dementing process
Any item, including food
Insidious. Usually starts in childhood/
adolescence and has a long natural
history before it becomes problematic
Any item, though hoarding of rotten food
(a) Information-processing deficits:
organization, memory difficulties;
(b) emotional attachment to possessions;
(c) behavioral avoidance; and
(d) erroneous beliefs about possessions
Generally selective (items are acquired/
hoarded according to their perceived
intrinsic, practical, or emotional value)
but can be more indiscriminate in some
Purposeful (items are hoarded for specific
emotional or practical reasons)
Hoarding apparently devoid of
identifiable cognitive and emotional
processes, although more research
Nature of acquiring
Generally indiscriminate but can be
more selective (acquisition of
specific items—e.g., umbrellas, or
according to their shape/color) in
Often purposeless (individuals display
little or no interest in the
Variable (some are able to discard
their possessions easily or do not
care if others discard them, whereas
others are very reluctant)
Frequent (especially in cases with
Utility of hoarding
Ability to discard
Inability to discard hoarded items is a core
feature of hoarding disorder and all
cases experience great distress when
discarding their possessions
Thought to be relatively uncommon
although more research is needed
Associated features Severe personality changes as well as
behaviors commonly attributable to
brain dysfunction such as gambling,
inappropriate sexual behavior,
excessive shopping leading to financial
difficulties, theft, stereotypies, tics,
and self-injurious behaviors
No severe personality changes or other
behaviors clearly attributable to
Excessive acquisition and shopping can be
Presence of a
diagnosis of OCD
Possible as a comorbid condition
(approximately 20% of cases), but
OCD not most frequent comorbidity
Mood and anxiety disorders more frequent
Insight ranges from good to poor or
absent. Initially, hoarding behavior can
be ego-syntonic; it becomes
increasingly distressing as clutter
increases and third parties intervene
InsightPoor or absent insight
Hoarding behavior appears to be
Note. OCD5obsessive-compulsive disorder.
Neuropsychological Correlates of Hoarding
Resting State Studies
In resting state studies, patients are instructed to lie down in the scanner with their eyes closed
and without being asked to perform any particular task. The results are then compared with
those of a healthy group. In one resting-state FDG-PET study (Saxena et al., 2004), 12 OCD
patients with predominantly hoarding symptoms had reduced glucose metabolism in the
posterior cingulate cortex (compared with healthy controls) and the dorsal anterior cingulate
cortex (compared with nonhoarding OCD). The severity of hoarding in the entire patient
group (n545) correlated negatively with metabolism in the latter region. It is important to
highlight that participants were originally recruited and enrolled based on a diagnosis of
OCD, not hoarding symptoms, and were retrospectively classified as having hoarding or
The same group of researchers attempted to replicate these findings in a sample of 20
medication-free adults with hoarding difficulties (10 of whom also had OCD) and 18 matched
controls (cited in Saxena, 2008). The authors found that hoarding individuals had significantly
lower glucose metabolism in bilateral dorsal and ventral anterior cingulate cortex than
controls (Saxena, 2008). Importantly, these individuals did not show brain metabolism
changes in regions typically associated with OCD. In the hoarding group, greater hoarding
severity was significantly correlated with lower relative metabolism in the right dorsal anterior
cingulate cortex, right posterior cingulate cortex, and bilateral putamen.
Another group of researchers (Ohtsuchi, Matsuo, Akimoto, & Watanabe, 2010) reported
on a 23-year-old female patient with severe OCD and prominent hoarding symptoms. Her
resting state SPECT scan revealed widespread hyperperfusion in the frontal cortex and
hypoperfusion in the bilateral striatum, the posterior part of the left anterior cingulate gyrus
and right medial temporal gyrus.
Symptom Provocation Studies
Symptom-provocation studies provide better experimental control because they allow
examination of the neural correlates of mental disorders when patients are currently
experiencing the symptoms. In the first of such studies, Mataix-Cols and colleagues (2004)
scanned a group of 16 OCD patients and matched controls while asking patients to imagine
discarding their possessions. This procedure was aided with the presentation of pictures of the
items to be discarded (e.g., old newspapers, toys, empty food containers). Both patients and
controls activated a similar network of brain regions in response to symptom provocation
but, compared with healthy controls, OCD patients showed greater activation in left
precentral (BA4/6) and fusiform (BA37) gyri and in right orbitofrontal cortex (BA11).
Furthermore, in the patient group, subjective anxiety during symptom provocation was
significantly correlated with activation in the left precentral gyrus (sensorimotor cortex).
However, only about half of the patients in this study endorsed hoarding symptoms on the
Y-BOCS Symptom Checklist and, therefore, these findings required replication in a
specifically selected sample of patients with more prominent hoarding symptoms.
The same group of researchers (An et al., 2009) recruited 13 OCD patients with prominent
hoarding symptoms, 16 patients with no hoarding symptoms, and 21 healthy controls. They
employed functional MRI and a symptom provocation procedure that comprised audio
instructions (e.g., ‘‘imagine that these objects belong to you and you must throw them away
forever’’) and pictures of items commonly hoarded by these patients. Subjective anxiety scores
suggested that the procedure was anxiety provoking for individuals with prominent hoarding.
The severity of hoarding symptoms correlated with the level of provoked anxiety.
In response to the hoarding-related (but not symptom-unrelated) anxiety provocation,
OCD patients with prominent hoarding symptoms showed greater activation in bilateral
anterior ventromedial prefrontal cortex (VMPFC) than patients without hoarding symptoms
and healthy controls. In the entire patient group (n529), provoked anxiety was positively
correlated with activation in a frontolimbic network that included the anterior VMPFC,
medial temporal structures, thalamus, and sensorimotor cortex. Negative correlations were
Journal of Clinical Psychology: In Session, May 2011
observed in the left dorsal anterior cingulate gyrus, bilateral temporal cortex, bilateral
dorsolateral/medial prefrontal regions, basal ganglia, and parieto-occipital regions. These
results were independent of the effects of age, sex, level of education, state anxiety, depression,
comorbidity, and use of medication. The main limitation of this study was that all participants
met criteria for OCD, and thus it is still unclear whether the results will extrapolate to
individuals with hoarding disorder.
Finally, Tolin and colleagues (2009) recruited 12 individuals with severe hoarding
symptoms (two of whom had OCD) and 12 healthy controls. The participants were scanned
(functional MRI) while making decisions about whether or not to discard personal paper
items, such as junk mail, brought to the laboratory as well as control items that did not belong
to them. Items were either saved or destroyed following each decision. Subjective anxiety
scores suggested that the decision-making process was highly anxiety provoking for the
hoarding individuals. When deciding whether to keep or discard personal possessions,
individuals with hoarding symptoms displayed increased activation in lateral orbitofrontal
cortex and parahippocampal gyrus compared with healthy controls. Among hoarding
participants, decisions to keep personal possessions were associated with greater activity in
superior temporal gyrus, middle temporal gyrus, medial frontal gyrus, anterior cingulate
cortex, precentral gyrus, and cerebellum than were decisions to discard personal possessions.
It is remarkablethatsimilar resultswere
(An et al., 2009) and primarily without (Tolin et al., 2009) OCD.
To summarize the preliminary evidence, the neuroimaging studies to date implicate
ventromedial prefrontal/cingulate and medial temporal regions in the mediation of
nonorganic hoarding symptoms. These findings are broadly consistent with the animal and
brain damage literature described above. This could indicate that organic and nonorganic
forms of hoarding would share similar neural substrates. Similarly, if further research confirms
that these brain regions are implicated in individuals with pure hoarding disorder (without
comorbid OCD), this would suggest that hoarding disorder may have partially distinct neural
substrates from OCD, which is characterized by involvement of frontal-striato-thalamic loops
(Saxena & Rauch, 2000).
obtained in hoardingsampleswith
Neuropsychology of Nonorganic Hoarding
A number of studies have examined the neuropsychological correlates of hoarding behavior.
Based on the animal, brain damage/dementia, and neuroimaging studies, one would predict
specific neuropsychological deficits in tasks that are sensitive to ventral fronto-limbic regions,
such as the IGT and reversal learning tasks. By contrast, these patients would be expected to
display intact performance on classic executive functions, such as response inhibition and
cognitive flexibility, which are characteristic of patients with OCD (Chamberlain, Fineberg,
Blackwell, Robbins, & Sahakian, 2006; Chamberlain et al., 2007). The evidence so far is mixed.
In one study (Hartl et al., 2004), 22 severe hoarders (four of whom met criteria for OCD)
had poorer delayed visual and verbal recall and used less effective organizational strategies
for visual recall compared with 24 healthy controls. Individuals with severe hoarding
also reported significantly less confidence in their memory and a greater level of worry
concerning the potentially catastrophic consequences of forgetting. Importantly, the results
remained significant after the exclusion of the four participants who also met criteria for OCD
(Hartl et al.).
In another study, OCD patients with prominent hoarding symptoms (n510) showed
impaired performance and blunted skin conductance responses during the IGT, whereas
nonhoarding OCD patients (n529) showed normal performance on this task (Lawrence et al.,
2006). By contrast, nonhoarding OCD participants displayed reduced cognitive flexibility on
the Wisconsin Card Sorting Test and normal performance on the IGT (Lawrence et al.).
Another set of researchers (Grisham, Brown, Savage, Steketee, & Barlow, 2007) studied a
group of 30 patients with compulsive hoarding and compared their results with a mixed
clinical group (n530) and a nonclinical community group (n530). The hoarding patients
demonstrated slower and more variable reaction time, increased impulsivity, greater difficulty
Neuropsychological Correlates of Hoarding
distinguishing targets and nontargets, and poorer spatial attention relative to comparison
groups. Multiple regression analyses demonstrated that slower reaction time and increased
impulsivity were significantly related to hoarding symptoms after controlling for the effect of
depression, schizotypy, and OCD symptoms. In this study, unlike Lawrence et al. (2006),
hoarding individuals had an equivalent performance on the IGT compared with nonhoarding
OCD patients and healthy controls. It is important to note that individuals in this study
reported hoarding as their principal (and in some cases only) OCD symptom, whereas
Lawrence and colleagues selected a subgroup of patients with additional hoarding symptoms
from a group of patients diagnosed with OCD. Grisham et al. (2007, p. 1480) speculated that
‘‘it is possible that patients whose primary psychiatric symptom is compulsive hoarding have a
somewhat different etiology and clinical presentation than OCD patients with additional
More recently, Grisham and colleagues (2010) administered a well-validated battery of
computerized neuropsychological tests to 19 severe hoarders and matched anxious (n517)
and healthy controls (n520). The authors administered the following subtests of the
Cambridge Neuropsychological Test Battery (CANTAB; Cambridge Cognition, 1995):
Affective Go/No-go (a response inhibition task), Cambridge Gambling Task (a decision
making test similar to the IGT), Intra-Extra Dimensional Set Shift (cognitive flexibility), and
Stockings of Cambridge (a planning/problem-solving task similar to the Tower of London
task). The results showed that hoarders were impaired only on the planning/problem-solving
task compared with the two control groups. There were no significant differences on any of the
Although indecisiveness is a noticeable clinical feature of hoarding disorder, performance
on laboratory tasks of decision making, such as the IGT or the Cambridge Gambling task,
was found to be impaired in only one of the three studies. It is possible that hoarders display
decision-making difficulties specific only to items of personal relevance, which would not be
captured by these standard neuropsychological tasks (Grisham et al., 2010). This is plausible
because, in general, hoarders have greater difficulty categorizing and discarding personal items
than nonpersonal items.
Taken together, it is difficult to draw firm conclusions from these early reports. First,
whereas some studies recruited OCD patients with hoarding symptoms (with different degrees
of severity), others recruited severe hoarding individuals predominantly without OCD.
Second, the neuropsychological tests employed were heterogeneous and tapping into different
domains. Third, only two of the studies employed psychiatric control groups.
Clinical Practices and Summary
The neural substrates of hoarding behavior in infrahuman animals are well-established.
By contrast, much less is known about normal and abnormal hoarding behavior in humans.
Useful clues come from case studies of brain-damaged patients and of individuals suffering
with dementia, particularly of the frontotemporal type. This research suggests that the
ventromedial prefrontal/anterior cingulate cortices as well as medial temporal regions may be
implicated in hoarding behavior. One theory is that the former cortical regions modulate or
suppress subcortically driven predispositions to acquire and collect and adjusts these
predispositions to environmental context (Anderson et al., 2005). Damage to these cortical
regions will result in dysregulated collecting and hoarding behavior. Although this model is
attractive, we need to be cautious in extrapolating these findings to nonorganic forms of
hoarding. Still, the neuroimaging literature of nonorganic hoarding has also implicated the
ventromedial prefrontal/anterior cingulate cortices and subcortical limbic structures (e.g.,
amygdala/hippocampus) in hoarding cases. However, the evidence is preliminary, obtained
from small samples, and confounded in many cases by the presence of comorbid OCD
The neuropsychological literature has, so far, been remarkably inconsistent; studies have
reported reduced performance on tasks of attention, memory, planning and decision making
but lack of replication is the norm. Like in the case of neuroimaging, the existing research is
Journal of Clinical Psychology: In Session, May 2011
severely limited by the recruitment of mixed groups of individuals with and without OCD.
Much more research is now needed to further delineate the neuropsychological profile that is
characteristic of hoarding disorder, that is, after the careful exclusion of individuals whose
hoarding is secondary to OCD. The creation of a new diagnostic category in DSM-V should
facilitate this task.
What then can we conclude from these composite findings for clinical practice? First,
practitioners may find Table 1 useful to differentiate between organic hoarding and hoarding
disorder. In particular, the former may be referred to for neurological and neuropsychological
evaluation. Second, psychotherapy and interventions likely to be beneficial in cases of organic
hoarding are different than those found effective in hoarding disorder. Cognitive-behavioral
therapy techniques that are effective for hoarding disorder may be less likely to be effective in
organic cases. Organic hoarders may be less willing to involve themselves in treatment and be
less compliant and concerned about their hoarding. It is possible that proportionally more of
the organic hoarders will require coordinated interventions by a variety of community
agencies (e.g., environmental health, adult protective services). Third, it is likely that advice
and the support needs of relatives and carers will differ between the groups. Fourth, prognosis
is likely to be poorer in organic cases, with admission to a residential facility being a more
likely and earlier outcome. Clearly, there is great need for evaluation of what works best in
both hoarding disorder and organic hoarding cases.
Selected References and Recommended Readings
An, S.K., Mataix-Cols, D., Lawrence, N.S., Wooderson, S., Giampietro, V., Speckens, A., et al. (2009).
To discard or not to discard: The neural basis of hoarding symptoms in obsessive-compulsive disorder.
Molecular Psychiatry, 14(3), 318–331.
Anderson, S.W., Damasio, H., & Damasio, A.R. (2005). A neural basis for collecting behaviour in
humans. Brain, 128(Pt 1), 201–212.
Cohen, L., Angladette, L., Benoit, N., & Pierrot-Deseilligny, C. (1999). A man who borrowed cars.
Lancet, 353(9146), 34.
Chamberlain, S.R., Fineberg, N.A., Blackwell, A.D., Robbins, T.W., & Sahakian, B.J. (2006). Motor
inhibition and cognitive flexibility in obsessive-compulsive disorder and trichotillomania. American
Journal of Psychiatry, 163(7), 1282–1284.
Chamberlain, S.R., Fineberg, N.A., Menzies, L.A., Blackwell, A.D., Bullmore, E.T., Robbins, T.W., et al.
(2007). Impaired cognitive flexibility and motor inhibition in unaffected first-degree relatives of
patients with obsessive-compulsive disorder. American Journal of Psychiatry, 164(2), 335–338.
Damecour, C.L., & Charron, M. (1998). Hoarding: A symptom, not a syndrome. Journal of Clinical
Psychiatry, 59(5), 267–272; quiz 273.
Frost, R.O., & Hartl, T.L. (1996). A cognitive-behavioral model of compulsive hoarding. Behaviour
Research and Therapy, 34(4), 341–350.
Frost, R.O., Steketee, G., & Williams, L. (2000). Hoarding: A community health problem. Health and
Social Care in the Community, 8(4), 229–234.
Grisham, J.R., Brown, T.A., Savage, C.R., Steketee, G., & Barlow, D.H. (2007). Neuropsychological
impairment associated with compulsive hoarding. Behaviour Research and Therapy, 45(7), 1471–1483.
Grisham, J.R., Norberg, M.M., Williams, A.D., Certoma, S.P., & Kadib, R. (2010). Categorization and
cognitive deficits in compulsive hoarding. Behaviour Research and Therapy, 48(9), 866–872.
Hahm, D.S., Kang, Y., Cheong, S.S., & Na, D.L. (2001). A compulsive collecting behavior following an
A-com aneurysmal rupture. Neurology, 56(3), 398–400.
Hartl, T.L., Frost, R.O., Allen, G.J., Deckersbach, T., Steketee, G., Duffany, S.R., et al. (2004). Actual
and perceived memory deficits in individuals with compulsive hoarding. Depress Anxiety, 20(2), 59–69.
Herberg, L.J., & Blundell, J.E. (1967). Lateral hypothalamus: Hoarding behavior elicited by electrical
stimulation. Science, 155(760), 349–350.
Hwang, J.P., Tsai, S.J., Yang, C.H., Liu, K.M., & Lirng, J.F. (1998). Hoarding behavior in dementia.
A preliminary report. American Journal of Geriatric Psychiatry, 6(4), 285–289.
Neuropsychological Correlates of Hoarding
Kalsbeek, A., De Bruin, J.P., Feenstra, M.G., Matthijssen, M.A., & Uylings, H.B. (1988). Neonatal Download full-text
thermal lesions of the mesolimbocortical dopaminergic projection decrease food-hoarding behavior.
Brain Research, 475(1), 80–90.
Kelley, A.E., & Stinus, L. (1985). Disappearance of hoarding behavior after 6-hydroxydopamine lesions of
the mesolimbic dopamine neurons and its reinstatement with L-dopa. Behavioral Neuroscience, 99(3),
Lawrence, N.S., Wooderson, S., Mataix-Cols, D., David, R., Speckens, A., & Phillips, M.L. (2006).
Decision making and set shifting impairments are associated with distinct symptom dimensions in
obsessive-compulsive disorder. Neuropsychology, 20(4), 409–419.
Leckman, J.F., Rauch, S.L., & Mataix-Cols, D. (2007). Symptom dimensions in obsessive-compulsive
disorder: Implications for the DSM-V. CNS Spectrums, 12(5), 376–387, 400.
Mataix-Cols, D., Frost, R.O., Pertusa, A., Clark, L.A., Saxena, S., Leckman, J.F., et al. (2010). Hoarding
disorder: A new diagnosis for DSM-V? Depression and Anxiety, 27(6), 556–572.
Mataix-Cols, D., Wooderson, S., Lawrence, N., Brammer, M.J., Speckens, A., & Phillips, M.L. (2004).
Distinct neural correlates of washing, checking, and hoarding symptom dimensions in obsessive-
compulsive disorder. Archives of General Psychiatry, 61(6), 564–576.
Mendez, M.F., & Shapira, J.S. (2008). The spectrum of recurrent thoughts and behaviors in
frontotemporal dementia. CNS Spectrums, 13(3), 202–208.
Nakaaki, S., Murata, Y., Sato, J., Shinagawa, Y., Hongo, J., Tatsumi, H., et al. (2007). Impairment of
decision-making cognition in a case of frontotemporal lobar degeneration (FTLD) presenting with
pathologic gambling and hoarding as the initial symptoms. Cognitive and Behavioral Neurology,
Ohtsuchi, H., Matsuo, K., Akimoto, T., & Watanabe, Y. (2010). Fronto-limbic abnormalities in a patient
with compulsive hoarding: A (99m)Tc-ECD SPECT study. Psychiatry and Clinical Neurosciences,
Pertusa, A., Frost, R.O., Fullana, M.A., Samuels, J., Steketee, G., Tolin, D., et al. (2010). Refining the
diagnostic boundaries of compulsive hoarding: A critical review. Clinical Psychology Review, 30,
Pertusa, A., Frost, R.O., & Mataix-Cols, D. (2010). When hoarding is a symptom of OCD: A case series
and implications for DSM-V. Behaviour Research and Therapy, 48(10), 1012–1020.
Pertusa, A., Fullana, M.A., Singh, S., Alonso, P., Menchon, J.M., & Mataix-Cols, D. (2008). Compulsive
hoarding: OCD symptom, distinct clinical syndrome, or both? American Journal of Psychiatry,
Saxena, S. (2008). Neurobiology and treatment of compulsive hoarding. CNS Spectrums, 13(9 Suppl 14),
Saxena, S., Brody, A.L., Maidment, K.M., Smith, E.C., Zohrabi, N., Katz, E., et al. (2004). Cerebral
glucose metabolism in obsessive-compulsive hoarding. American Journal of Psychiatry, 161(6),
Saxena, S., & Rauch, S.L. (2000). Functional neuroimaging and the neuroanatomy of obsessive-
compulsive disorder. Psychiatric Clinics of North America, 23(3), 563–586.
Snowdon, J., & Halliday, G. (2011). A study of severe domestic squalor: 173 cases referred to an old age
psychiatry service. International Psychogeriatrics, 23(2), 308–314.
Steketee, G., & Frost, R. (2003). Compulsive hoarding: Current status of the research. Clinical Psychology
Review, 23(7), 905–927.
Thomas, N.D. (1997). Hoarding: Eccentricity or pathology: When to intervene? Journal of Gerontological
Social Work, 29(1), 45–55.
Tolin, D.F., Kiehl, K.A., Worhunsky, P., Book, G.A., & Maltby, N. (2009). An exploratory study of the
neural mechanisms of decision making in compulsive hoarding. Psychological Medicine, 39(2),
Volle, E., Beato, R., Levy, R., & Dubois, B. (2002). Forced collectionism after orbitofrontal damage.
Neurology, 58(3), 488–490.
Journal of Clinical Psychology: In Session, May 2011