800px-Compulsive_hoarding_Apartment January 03

Help the Hoarders!

I am—like most of my neuroscientist and psychologist colleagues, I’m sure—a mental hypochondriac. As a nervous perfectionist and self-proclaimed weirdo with a laundry list of mild psychiatric conditions (professionally and personally diagnosed), my interest in neuroscience has always been driven by a selfish desire to know more about myself and my strange brain (link art by Emilio Garcia, check him out!).

Last year (it’s 2014, y’all!), hoarding was added to the Fifth Edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) as a disorder distinct from obsessive-compulsive disorder (OCD) and obsessive-compulsive personality disorder (OCPD). This struck me as an obvious decision, as I have frequently diagnosed myself with both OCPD and compulsive hoarding but never at the same time, although hoarding used to be a requisite of the OCPD diagnosis.


Thankfully, this was the best/worst example of hoarding that I could find (and wished to share). My current collection of NYT magazines, Science, Bon Appetit, Mass Appeal, etc. Not that bad!!  Phew!!  Also, I wanted to show you this dog that isn’t mine and the mouse mask on my record player…

When I am overwhelmed with stress, I often have the compulsions to pick my hair and to shake my head. Though not a symptom of OCD or OCPD, my compulsive tic is one of the reasons a former professor at UC San Diego offered to accompany me to visit a neurologist, but not something I’ve ever desired to tell my psychologist (she might think I’m crazy!.. a discussion we can save for another post). Though my experience with trichotillomania (hair-picking, for those of you who didn’t follow the link) is mostly unconscious, my tic compulsion is similar to that which forced me to reorganize my desk before beginning to write this article. Compulsions like these have struck me often throughout my life (another example with which you may relate: “If you scratch the left side of your head, you must scratch the right!”), but I do not associate them with my tendency to hoard.


Oh, but there was my cardboard box collection that I was forced to recycle when I moved out of graduate housing… :\

Anyway, back to the topic of hoarding disorder in the DSM-5…

Hoarding in the DSM

Although originally a trait of “anal character” (which was thankfully renamed OCPD, or “anankastic personality disorder” in the International Classification of Diseases), hoarding was not added as a criterion for OCPD until the DSM-III-R (see Wikipedia for an explanation of the III and the R). In order to be diagnosed with OCPD in the DSM-IV-TR (which preceded DSM-5), an individual must exhibit four or more of the following: (1) hoarding—specifically “the inability to discard worn-out or worthless objects even when they have no sentimental value”; (2) preoccupation with details, rules, lists, etc.; (3) perfectionism that interferes with task completion; (4) excessive devotion to work and productivity; (5) inflexibility about matters of morality, ethics, or values; (6) reluctance to delegate tasks or work with others; (7) miserliness; and (8) rigidity/stubbornness.

OCPD is distinguished from OCD by its lack of “true obsessions and compulsions.”  Additionally, hoarding is not considered a typical symptom of OCD, though it is a potential symptom of OCD, and confusingly, in the DSM-IV-TR, “A diagnosis of OCD should be considered especially when hoarding is extreme.” In other words, the relationship between OCPD, OCD, and hoarding is confusing. Or it was, before the DSM-5.

The working definition of “compulsive hoarding,” established and modified by Dr. Randy Frost and colleagues (Frost and Hartl, 1996), requires: difficulty discarding or parting with personal possessions, due to strong urges to save items, distress, and/or indecision associated with discarding; the accumulation of a large number of possessions that prevent normal use of the space; and significant distress or impairment in important areas of functioning none of which is not due to a general medical condition (such as brain injury or cerebroventricular disease). Given the different possible explanations for hoarding, discussed below, these hoarding symptoms are not restricted to symptoms of another disorder, including OCD, major depressive disorder, or schizophrenia.

In preparation for the DSM-5, Dr. David Mataix-Cols, one of the leaders in OCD-related research, discussed the reasoning behind and benefits of removing hoarding as a criterion of OCPD and listing it as a distinct disorder (Mataix-Cols et al., 2010). In terms of OCD and OCPD, one could think of the fear of losing possessions as an “obsession” and the urges to save and acquire possessions as “compulsions.” Despite the semantic associations between OCD, OCPD, and compulsive hoarding, however, factor and cluster analyses  have found that hoarding is distinct and independent of the other symptoms of OCD (Bloch et al., 2008). That is, most other symptoms of OCD (such as symmetry obsessions, ordering, and repetition) are much more correlated with one another than any are with hoarding.

As I have noticed from personal experience, hoarding-related thoughts, in contrast to other obsessions/compulsions, are not intrusive. For OCD sufferers, (non-hoarding) obsessions are often distressing and unpleasant, and most patients with OCD seek help out of their own volition. Hoarders, however, associate the accumulation of possessions with euphoria and satisfaction and tend to be distressed only when faced with the threat of losing or discarding their possessions. Furthermore, hoarders are often in denial of their problems and are usually forced by family members to get help. In other words, (I hypothesize) while OCD is driven by negative reinforcement, hoarding is driven by positive reinforcement. This may be related to other cognitive-behavioral and anatomical differences between OCD and hoarding patients.

Hoarding and the Brain

Compared to healthy control subjects and non-hoarding OCD patients, compulsive hoarders have deficits of attention, memory, categorization of objects, and decision-making (Frost and Hartl, 1996; Grisham et al., 2007; Blom et al., 2011; Tolin et al., 2012). Neuroimaging studies have found corroborating evidence for the differences between non-hoarding OCD patients and hoarders.

Compulsive hoarders have abnormal resting state functional brain imaging patterns that are different from both controls and non-hoarding OCD patients. OCD symptoms are mediated by elevated activity in specific orbito-striatal-pallidal-thalamic circuits, while hoarding is mediated by distinct fronto-limbic circuits involving low activity of the anterior cingulated cortex, ventromedial cortex, and subcortical limbic structures (Mataix-Cols et al., 2010). In a functional imaging study of hoarding and non-hoarding OCD patients deciding to discard their own or others’ possessions (such as junk mail and newspapers), hoarding patients had abnormal activity in the anterior cingulate and insula. Activity was low when patients were shown items that did not belong to them and very high when they were shown items that did belong to them. These differences correlated with hoarding severity and self-ratings of indecisiveness. The authors concluded that these abnormalities related to “problems in identifying the emotional significance of a stimulus, generating appropriate emotional response, or regulating affective state during decision making” (Tolin et al., 2012).

Taken together, these findings support the decision to establish hoarding as its own disorder. Although it is still in the chapter “Obsessive-Compulsive and Related Disorders,” some studies suggest that hoarding may be more similar to impulse control disorders (ICDs), such as alcoholism and gambling addictions. Hoarding, like ICDs, involves preoccupation with accumulation of possessions, denial of a problem, excuses for problematic behavior, and neglect of personal and environmental conditions (Reinisch, 2008).  Furthermore, impulsivity seems to contribute to hoarding symptoms in clinical studies, although the relationship between the two symptoms is unclear (Grisham et al., 2007; Timpano et al., 2013).

As a behavioral neuroscientist interested in animal models of psychiatric illnesses, I did a quick Google search for animal models of hoarding. This, as I should have guessed, led me back to an old addiction of mine that I had been actively trying to avoid…


Animal hoarding is a terrible issue that endangers the lives of hoarders, their animals, and their communities.  Animal hoarding is a complex problem to solve, since it involves social and health services for the patients, as well as animal protection officers and veterinarians for the animals.  There may be somewhere between 700 and 2,000 new cases of animal hoarding the US every year (Patronek, 1999), and terrifyingly, after animals are removed from the homes of hoarders, the rate of relapses is over 50% (Berry et al., 2005)!

Confessions: Animal Hoarding is on Netflix, and I have watched every episode (FIVE STARS!).

I will post this BertStrip in place of evidence of my own animal hoarding. Not that I am hoarding animals or anything…

Some possible causes of animal hoarding (Reinisch, 2008):

  • dementia: no insight or empathy for the animals
  • delusional disorder: special ability to understand and empathize with the animals; delusion that the animals are healthy
  • addiction: impulse control is impaired and they feel the need to get more animals even if it is destructive
  • childhood trauma: leading to the inability to establish human relationships that forces hoarders to seek the love of animals
  • aging: neglect and isolation of the aging, who may suffer from poor medical care and extreme clutter, may also lead to the unhealthy and unchecked hoarding of animals

20-30% of patients with OCD exhibit hoarding of animals or inanimate objects, and the above may also apply to object hoarding.

But are object and animal hoarding the same? Frost, Patronek, and Rosenfield (2011) have compared the two extensively. (Dr. Gary Patronek is the go-to guy for animal hoarding research!) One difference, for example, is that multiple types of objects are hoarded whereas many animal hoarders keep only one or two species of animal (in one study by of 54 case reports, cats were involved in 65% of cases, dogs in 60%, farm animals in 11%, and birds in 11%; 35.2% involved a single species and 31.5% involved two; Patronek, 1999). Additionally, animal hoarders often have squalid living conditions, which are not as common in object hoarders.  Overall, however, not enough is known about animal hoarding to warrant a distinct diagnosis.

Hoarding is a public health issue!

Whether or not we categorize hoarding as a disorder of compulsivity, impulsivity, or neither, it remains a devastating public health issue. It is dangerous to have a lot of stuff in your house!  You could trip or not be able to escape in a fire, and that is scary! Ammonia from animal urine is even more dangerous! Compulsive hoarding occurs in 2 to 5% of the population, so I think it’s time to take hoarding seriously as a mental illness, and not just as a fascinating and grotesque quirk to watch on TV! I hope that now that it is in the DSM it will get the attention it needs.

As we begin the new year, I hope those of us who are able will tone down the hoarding and be sensitive to those who can’t. And to those of you who can’t—seek help!!  You might get to meet Dr. Patronek!


    Blom RM, Samuels JF, Grados M a, Chen Y, Bienvenu OJ, Riddle M a, Liang K-Y, Brandt J, Nestadt G (2011) Cognitive functioning in compulsive hoarding. J Anxiety Disord 25:1139–1144 Available at: http://www.ncbi.nlm.nih.gov/pubmed/21906910
    Grisham JR, Brown T a, Savage CR, Steketee G, Barlow DH (2007) Neuropsychological impairment associated with compulsive hoarding. Behav Res Ther 45:1471–1483 Available at: http://www.ncbi.nlm.nih.gov/pubmed/17341416
    Mataix-Cols D, Frost RO, Pertusa A, Clark LA, Saxena S, Leckman JF, Stein DJ, Matsunaga H, Wilhelm S (2010) Hoarding disorder: a new diagnosis for DSM-V? Depress Anxiety 27:556–572 Available at: http://www.ncbi.nlm.nih.gov/pubmed/20336805
    Timpano KR, Rasmussen J, Exner C, Rief W, Schmidt NB, Wilhelm S (2013) Hoarding and the multi-faceted construct of impulsivity: a cross-cultural investigation. J Psychiatr Res 47:363–370 Available at: http://www.ncbi.nlm.nih.gov/pubmed/23168138

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